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Design of a management information system for the Shielding Experimental Reactor ageing management
Nuclear Engineering and Design 240 (2010) 103–111
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Nuclear Engineering and Design journal homepage: www.elsevier.com/locate/nucengdes
Design of a management information system for the Shielding Experimental Reactor ageing management Jie He ∗ , Xianhong Xu Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, PR China
a r t i c l e
i n f o
Article history: Received 21 June 2008 Received in revised form 26 August 2009 Accepted 9 October 2009
a b s t r a c t The problem of nuclear reactor ageing is a topic of increasing importance in nuclear safety recent years. Ageing management is usually implemented for reactors maintenance. In the practice, a large number of data and records need to be processed. However, there are few professional software applications that aid reactor ageing management, especially for research reactors. This paper introduces the design of a new web-based management information system (MIS), named the Shielding Experimental Reactor Ageing Management Information System (SERAMIS). It is an auxiliary means that helps to collect data, keep records, and retrieve information for a research reactor ageing management. The Java2 Enterprise Edition (J2EE) and network database techniques, such as three-tiered model, Model-View-Controller architecture, transaction-oriented operations, and JavaScript techniques, are used in the development of this system. The functionalities of the application cover periodic safety review (PSR), regulatory references, data inspection, and SSCs classification according to ageing management methodology. Data and examples are presented to demonstrate the functionalities. For future work, techniques of data mining will be employed to support decision-making. © 2009 Elsevier B.V. All rights reserved.
1. Introduction The International Atomic Energy Agency (IAEA), defines reactor ageing as a general process in which characteristics of systems, structures and components (SSCs) gradually change with time or use (IAEA, 1995). This process eventually leads to degradation of materials and components subjected to normal service conditions. Without preventive measures, ageing can result in equipment and component failures. In order to ensure safety and reliability of continued operation, it is very important to implement ageing management programs (AMPs) for reactors. A number of authoritative articles have indicated the significance and necessity of software tools in reactor ageing management. IAEA (1991) indicates how to classify data related to ageing management and manage them efficiently. Computers are recommended to help process the data involved in ageing management. In that article, data are classified into three categories, i.e. baseline information, operating history data, and maintenance history data. IAEA (1999, 2003a, 2004a,b) indicate that database applications and database management system (DBMS) along with other hardware and software can serve as engineering tools for operation and ageing management. Furthermore, at a workshop of IAEA, data collection and record keeping is noted as one of the
∗ Corresponding author. Tel.: +1 919 455 3879. E-mail address: [email protected] (J. He). 0029-5493/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.nucengdes.2009.10.017
key issues in an ageing management program (Hakim, 2006). These works have demonstrated the importance of database applications to reactor ageing management but do not elaborate how to design and implement a software system. Helmut et al. (2006) introduces the AREVA’s software tool COMSY for ageing management, but this is for reactors in nuclear power plants (NPPs), rather than research reactors. Xinjun et al. (2005) introduces database systems used for research reactor operation management. The systems are helpful to data collection and storage, but the systems are not professional for ageing management use. In fact, there are few professional software systems developed for reactor ageing management around the world, especially for research reactors. The Shielding Experimental Reactor (Fig. 1) at Tshinghua University is a twin-core pool type research reactor (RR), which was commissioned in 1964. Ageing management has been implemented since early-1980s, with the documentation being processed manually without computer aids. This paper presents pioneering work in MIS development for the Shielding Experimental Reactor, which sets an example to general research reactors ageing management. An ‘MIS’ is a planned system of the collecting, processing, storing and disseminating data in the form of information needed to carry out the functions of management. The authors of this paper recently developed the MIS based on a browser/server (B/S) mode by J2EE. This is a part of the studies on the Shielding Experimental Reactor ageing management. The objective of the applications is to support the ageing management program. Our presentation (He, 2006) talked about the design of the system at the IAEA workshop
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Fig. 1. Exterior of the Shielding Experimental Reactor.
at Tsinghua University 2006. Some design ideas of this MIS are taken from the participants’ presentations at that workshop. This paper first reviews the background of the reactor ageing management program. Then, the architecture of the SERAMIS modules is introduced, including the elaboration of the programming of J2EE technology. In particular, several primary functions of this system are presented to show how they meet the demands of ageing management regulations and practice. For further clarity, some examples are given. Conclusions and future work are discussed by the end. 2. Software design criteria In the practice of reactor ageing management, safety-related work requires systematic, strict, and specialized studies. Software should also meet this requirement. IAEA (2005) proposes software to be included into reactor safety management as well as important SSCs. Therefore, how well this software tool applies to the methodology of nuclear safety management is important. Another objective of the MIS lies in data inspection and analysis. We need to process observations from periodic inspections to analyze ageing and environmental impacts. Robust capability of data processing is our goal. Generally, we try to make the MIS meet the following basic requirements: • Software itself should be safe and secure. • Data security should be ensured. • Both reactor SSCs and environmental monitoring should be included. • SSCs are classified according to regulations. • Abnormal observations can be preliminarily detected by embedded inspectors. • The system is equipped with basic statistical tools for ageing analysis. • User access control and human factors are taken into consideration.
• Accessing the system is convenient and its interfaces are userfriendly. Since SERAMIS development is ongoing, these requirements may be insufficient, and improvements are anticipated. 3. Modules in SERAMIS After login, users reach the menu of SERAMIS. Users can choose out of the four modules by clicking the buttons on the left. The four modules are: Guidelines, SSCs records, Service conditions and environment, and IAEA documentations. The structured data of the modules are stored in relational databases, managed by MS SQL Server. The Guidelines module provides users with the introductions to reactor ageing management, the summary of Shielding Experimental Reactor (Fig. 2), and the ageing management programs. The module directs users to implement AMPs of this reactor. The SSCs records module manages the data of SSCs important to safety. These data include baseline information, operating history data, and maintenance history data mentioned in IAEA (1991). The majority of these data are PSR records. The PSR is not only defined as the overall assessment of the whole reactor every 10 years (IAEA, 2003b), but also specific to every component reviewed at shorter intervals. We implement periodic testing according to IAEA (2006) and store results via this module. Besides numerical data, the photos and videos of visible ageing features (for example, the change of color, shape, and the appearance of cracks and corrosion spots) are also kept in the system (Fig. 3). The module of Service conditions and environment helps to monitor the condition of SSCs, ageing and safety performance of the reactor, and its radiological impact on the environment (IAEA, 2005). The service conditions are what affect material properties or functional capabilities, or lead to obsolescence and affect reactor safety (IAEA, 1995). The IAEA documentations module is a collection of safety guides and series related to ageing management. Since IAEA plays a key
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Fig. 2. A user interface in the ‘Guidelines’ module of SERAMIS showing the introduction to the Shielding Experimental Reactor.
Fig. 3. A user interface in the ‘SSCs records’ module of SERAMIS showing a photo of corrosion on the inner surface of the pool tank.
role in the global nuclear field, its documentations have authoritative weight. The AMPs of our reactor follow these guides. This module provides convenient references for users to download them or read online. Entered into SERAMIS, data are stored in relational databases. All of the four modules allow for operations of insertion, deletion, updating, and query on data by the users who are granted permission. Questionable or abnormal data can be detected by an automatic inspector to warn users to make a further diagnosis. Statistical graphs are available for data analysis. The overview of the SERAMIS modules is shown in Fig. 4. 4. Programming implementation SERAMIS is based on browser/server (B/S) mode. This mode allows the user access the server with identified username and password from wherever an internet connection is available. There is no need to install any client-side software.
The applications were programmed by Java, HTML, and JavaScript, attached to MS SQL Server via JDBC. The J2EE web technology is important to the development of SERAMIS. J2EE is a Java2 Enterprise Edition developed by Sun Microsystems. The J2EE applications provide platform independence, easy access of users, and global communication among engineering team members located dispersedly (Huang et al., 2004). HTML stands for Hypertext Markup Language and is widely used on the World Wide Web. It describes the text, images, and other objects in web pages. HTML files with Java tags embedded in are called Java server page (JSP) files. JSPs are compiled by the web server and output to HTML for user browsing. The web browser (e.g. Microsoft Internet Explorer) is the tool to interpret HTML. JavaScript (developed by Netscape) is a client-side object-based scripting language, which can be included on web pages to make them more interactive. A Java database connectivity (JDBC) is needed to provide a set of Java classes and interfaces so that Java server programs can access DBMS.
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Fig. 4. Scheme of the architecture of SERAMIS.
The following are representative programming techniques used in SERAMIS development. Some of them are for the consideration of system reliability and stability. 4.1. Three-tiered model From a programming aspect, SERAMIS consists of three tiers, i.e. the presentation tier, middle tier, and database tier (Fig. 5). This is the typical architecture of the B/S mode. In presentation tier, the applications render the user interface in HTML. Users access SERAMIS like browsing web pages from a website. The middle tier is also called business logic tier. In this tier, the server components are stored on a web server—Tomcat. It serves as a container. A servlet is a Java program that runs in this container. Typically, the servlet receives an hypertext transfer protocol (HTTP) request from a browser, generates dynamic content (such as by querying a database), and provides an HTTP response
back to the browser. Servlets or JSPs invoke the public methods in data access objects (DAOs) to access databases through the JDBC driver. In database tier, MS SQL Server manages all the data stored on hard disks and provides ports for the middle tie accessing. Compared with the two-tiered client/server (C/S) model, developers of three-tier do not have to develop and update client-side applications considering clients’ complex environments. 4.2. Model-View-Controller architecture In the presentation and middle tiers, the application components are developed following the pattern of Model-ViewController (MVC). The MVC architecture is a way of decomposing the application components into three parts: the Model, the View, and the Controller (Gulzar, 2003). A Model is in charge of accessing and manipulating database usually by SQL. The View is to forward user input to the Controller and present the outcomes of Model
Fig. 5. Browser accessing data through the SERAMIS’s three tier.
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to users. The Controller is the intermediate between the View and Model, translating user input into actions to be performed by the Model. As for SERAMIS, HTML files and JSPs compose the ‘View’; servlets act as ‘Controller’; DAOs belong to ‘Model’. In MVC architecture, the three parts are developed independently and functional programs are specified separately. In this case, Software framework and component reuse becomes easy. The reuse can enhance the efficiency of software development, offer clear responsibilities between web page designers and software developers, and improve system maintainability and extensibility (Li et al., 2006). 4.3. Transaction-oriented database operations A transaction is a short sequence of operations with the database which represents one meaningful activity in the users’ environment. It is treated as a logical unit of work that cannot be divided into pieces with respect to concurrency and recovery. We adopt this technology in order to avoid data inconsistency caused by unexpected accidents. For example, we are going to update the records of a reactor component in the database. There are two tables storing the data related to this component, which means both of them need to be updated. Computer executes the operations on the two tables one after another. However, without transaction-oriented programming, if the system happens to break down after the operation on the first table, the operations on the second table may not be executed successfully. As a result, data inconsistency occurs: data in the first table are updated but data in the second table are not. This may cause contradiction in ageing management. To avoid this exception, we widely use the following Java code for database operations: conn.setAutoCommit(false) and conn.commit(). These two statements can effectively prevent data inconsistency. Every single statement between the two statements cannot be submitted unless all of the statements are executed successfully because they are considered a logical unit of work—transaction. Data consistency is guaranteed. 4.4. JavaScript programs Structured data management requires data be in proper format before entered into database. In SERAMIS development JavaScript is mainly used for input verification and data inspection. Since JavaScript is a client-side language that can be interpreted by the browser, it is much easier to verify the input data by JavaScript programs than by server-side languages. In addition, detecting questionable or abnormal data with ageing criteria can also be easily implemented by JavaScript programs. In case that JavaScript requires proper environments on clients’ computers, for complicated data mining, server-side programming (e.g. JSP) will be considered to process data, instead of JavaScript.
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ageing effect on a certain SSCs may become more important than before. This situation calls for renewed criteria, frequent tests, and periodic safety reviews (Myung et al., 2004; Winfield, 2006). Therefore, it is necessary to continually update these records. For this purpose, SERAMIS has the functionality of reminding users to regularly update the data and files. Ageing criteria and observations are marked with time when created in the systems. The user is asked to denote a period of validity (e.g. how many months or years) or inspection frequency (e.g. weekly, annually, or 5 yearly) for them. When it is approaching the expiration, the system proposes notification on reinvestigation. Updated criteria observations are marked with new date. This function serves as a safeguard so that out-of-date records are not used for decision-making. 5.2. Data inspection To discover potential ageing problems, it is necessary to detect abnormal data from observations, according to technical standards. After retrieving data from the database, the system can be requested to inspect the data to see whether or not the observation values meet the safety criteria specified by users. Abnormal data will be colored as a warning. This process can be completed by embedded programs of JavaScript. The following paragraphs introduce an example that how SERAMIS helps us to detect questionable data of electrical cables on reactor devices. The ageing management of cables is important to a reactor, which is particularly introduced by IAEA technical documents (IAEA, 1997, 2000). Electrical cables on reactor devices are exposed to various environmental conditions (physical/chemical), such as temperature, water vapor, or ionizing radiation, etc. These environmental service conditions induce ageing processes at the molecular level of the materials. Loss of cable functionality is usually determined by the changes in mechanical properties, cracking of the insulation preceding electrical failure (i.e. loss of insulation resistance) (IAEA, 2000). As for the Shielding Experimental Reactor, changes of electrical properties on the cables in long-term service may cause degradation in the functional characteristics. To diagnose the degradation, periodic inspections on cables are carried out at the interval of 1 or 2 years. Fig. 6 shows detected electric resistance of the insulating layers on cables. The ageing features of a cable mainly lie in the degradation of its insulating materials. In this table, the letters A, B, and C, respectively, represent the wires of the three phases wrapped in one cable. Cells with missing data are colored in grey. Abnormal data are defined as the following criteria. • The safety limit is assumed as r0 M. If a resistance value is below it, i.e.: r < r0 the table cell containing it appears pink. • Although environment conditions can result in slight fluctuations in observations, large differences between consecutive yearly observations of the same item are questionable. We consider:
5. Functionalities of SERAMIS Besides data storage, other functionalities are also developed in light of ageing management methodology. 5.1. Reminder for PSR data updates As the operating conditions gradually change with time or use, the trends and inducements of ageing often change as well. Some
|rn+1 − rn | > rt to be abnormal. The rn and rn+1 represent the resistance observed by consecutive detections, and rt represents the acceptable maximum difference. Consecutive observations that fluctuate sharply are colored blue. • As time goes by, only monotonic drop of resistance is considered reasonable. Table cells containing increasing resistance
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Fig. 6. PSR data of the resistance of insulating layers on cables for electrical equipments, with questionable observations automatically colored by SERAMIS as a warning (unit: megaohm).
data, i.e.: rn < rn+1 are colored yellow. The subscript ‘n’ and ‘n + 1’ represent consecutive yearly detections. The parameters can be defined and refined by users according to specific circumstances. Fig. 7 shows the user interface for specifying the criteria. Users are allowed to set any of the three criteria by checking off the boxes and filling in values for thresholds. In this example, we let: r0 = 5 megaohm rt = 100 megaohm. Questionable data in Fig. 6 are colored for distinction. 5.3. Assistance with SSCs classification SERAMIS helps with the classification management of SSCs according to IAEA (1995, 2005). There are no more than a dozen ageing mechanisms that cause thousands of SSCs ageing in reactor
SSCs. In most cases, ageing problems on similar SSCs are often analyzed synthetically. Meanwhile, technical and financial problems should also be taken into consideration if we want to modify or replace a component. So, it is necessary to classify SSCs into categories regarding the similarities in ageing management among them. Table 1 shows some of the classified SSCs of the Shielding Experimental Reactor with the abbreviations explained in Table 2. In SERAMIS, 12 frequent mechanisms of SSCs ageing, such as Corrosion, Radiation, Temperature, Pressure, etc., are listed for selection. Since ageing is often caused by two or more mechanisms jointly, one or two most important mechanisms are picked out as ‘principal ageing mechanism’ to highlight its ageing features. Meanwhile, SERAMIS rates the ease of SSCs replacement into four levels, namely, No, Difficult, Normal, and Readily. This property is designated by experts. The replacement difficulty of the same component may vary from case to case, depending on where it is installed and its environments. For example, the replacement of cables for accessory devices is not as difficult as that for in-core equipments. Such components are usually noted with two different ease rates. Experts are asked to denote the rates when entering SSCs records into the system. When working on a refurbishment program of SSCs, SERAMIS
Fig. 7. An interface of user-defined criteria of abnormal data for automatic inspection.
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Table 1 List of the Shielding Experimental Reactor systems concerning their importance to safety and replacement ease. Items
Safety related
Replacement ease
Ageing mechanisms
Predominant ageing mechanisms
Beam tubes Biological shielding Cables Communication Control rods/mechanisms Control systems Crane Fire protection Fuel elements/storage Measuring instrumentations Pool internals Primary cooling systems Protection systems Purification systems Radiation monitoring systems Reflector Secondary cooling systems Shutdown systems Signal devices Tank UPS systems Water supply systems
Y Y M M Y Y M Y Y M Y M Y M Y Y N Y Y Y Y N
A/B A B/C C/D C C B/C B C C B B/C B C C C C C C A B/C C
3,5,12 1,2,3,4,5 1,2,5,12 5,12 1,4,5,12 2,4,6,12 4,5,12 5,12 1,2,5 1,2,4,6,12 1,4,5,6,7 1,4,5,6,7,12 4,5,12 1,2,5,12 5,12 1,4,5,12 4,5,6,7,12 4,5,12 2,4,6,12 1,2,4,5,6,12 5,6,12 5,12
5 1,5 12 12 12 12 12 12 1,5 12 1,5 7 12 12 12 12 12 12 12 5 12 12
Table 2 Abbreviations.
5.6. Basic statistical analysis
Safety related
Replacement ease
Mechanisms
Y—Yes N—No M—Maybe
A—No B—Difficult (tech. or costly) C—Normal D—Readily
1—Radiation 2—Temperature 3—Pressure 4—Cycling 5—Corrosion 6—Chemical 7—Erosion 8—Technology changes 9—Safety requirements 10—Documentation 11—Human factors 12—Design/operation/ maintenance
users can inquire about the ageing mechanism and replacement difficulty.
Statistical analysis reveals data characteristics from the observations, and displays them on web pages. The calculation is performed in the middle tier by mathematical functions of the system. The frequently used statistical parameters are sum, mean, mode, maximum, minimum, and deviation. As an example, Tables 3 and 4 show measurements of the yearly PSR of the six control rods withdrawal and scramming velocity. The velocity of rods rising and dropping is measured in terms of ‘second/millimeter’ (s/mm). We measured the time consumption while a safety rod rises or drops across the whole altitude of 600 mm for emergency shutdown, and while automatic or manual rods move up or down across 100 mm to control the reactor power. In Fig. 8, the plots of the yearly measurements of manual rods from Table 4 are joined by line segments. From the graphs we can see the measurements are nearly constant and manual rods are not seriously ageing during the period from 1996 to 2004. The functionality of statistical analysis makes it easier for users to perceive the observations.
5.4. User access control In order to enhance security and clarify commitment, different users are given their unique authority that restricts the scope of access to the data, AMPs, and regulations. The system also distinguishes different users’ roles in ageing management. As an example, for modification permission, only safety committee or experts are qualified to revise them. Users are merely entitled to read the records related to their work rather than revise any records, unless they are granted to do so. 5.5. Guides according to AMPs and regulations Since ageing management is involved in the safety of nuclear reactor, most activities (e.g. SSCs replacement or modification) must obey AMPs and regulations. There are introductions to the activities in SERAMIS, such as in-service inspection (ISI), assessment, and preventive maintenance. Users can consult the introductions when implementing AMPs so that operations can progress methodically. Moreover, special tests or modifications are highlighted to ensure modifications on the facilities are approved by safety committee and regulators (if required) prior to implementation (Winfield, 2006). Unlicensed modifications are not acceptable.
Fig. 8. Plots and fitted lines of the yearly measurements of the safety rods and automatic rod dropping velocity.
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Table 3 Periodic test results of the velocity of safety rods and automatic rod rising/dropping of core 2. Test date
2004/06 2003/06 2002/06 2001/06 2000/06 1999/06 1998/06 1997/06 1996/12
Safety rod 1#
Safety rod 2#
Automatic rod
Rising (s/600 mm)
Dropping (s/600 mm)
Rising (s/600 mm)
Dropping (s/600 mm)
Rising (s/100 mm)
Dropping (s/100 mm)
18.41 16.25 19.54 18.29 18.92 18.84 23.38 18.43 22.82
0.72 0.66 0.67 1.00 0.85 0.48 0.67 0.69 0.76
20.09 17.65 20.15 18.13 20.21 20.78 22.04 18.37 22.26
0.79 0.77 0.65 0.99 0.70 0.45 0.63 0.54 0.50
24.58 23.49 22.89 23.77 26.23 25.57 27.67 21.06 25.46
1.88 1.95 1.89 1.67 1.93 1.59 2.13 1.94 1.69
Table 4 Periodic test results of the velocity of manual control rods rising/dropping of core 2. Test date
2004/06 2003/06 2002/06 2001/06 2000/06 1999/06 1998/06 1997/06 1996/12
Manual rod 1#
Manual rod 2#
Manual rod 3#
Rising (s/100 mm)
Dropping (s/100 mm)
Rising (s/100 mm)
Dropping (s/100 mm)
Rising (s/100 mm)
Dropping (s/100 mm)
30.58 28.55 30.05 29.11 29.92 29.54 30.71 28.88 28.96
27.88 28.55 28.34 27.29 28.77 28.44 29.55 26.51 26.00
30.90 28.08 30.22 29.63 30.17 28.22 29.64 27.58 28.16
26.90 27.30 27.98 27.88 27.93 27.22 28.53 25.31 26.00
34.21 27.06 27.56 26.34 27.32 27.06 28.90 26.41 26.21
28.34 28.11 28.03 27.80 29.40 28.53 30.12 28.78 28.00
Currently, the SERAMIS has only elementary functionalities for statistics. In the near future we will improve this part. 6. Conclusions and future work This paper sets a generic example of MIS affiliated with reactor ageing management in nuclear industry. SERAMIS development is a multidisciplinary task, drawing work from nuclear engineering, computer science, and statistics. We try to design a helpful MIS causing the ageing management, procedure, and operation to take on its desirable configuration in efficient way. In this case, a minimum of economic cost and maximum of safety control can be achieved. As a reference, AREVA’s software tool COMSY (Helmut et al., 2006) is a very useful software tool for NPP ageing trend analysis, especially on pressure pipes and vessels ageing. In these aspects, COMSY is more functional than SERAMIS. Nevertheless, SERAMIS has some other advantages in RR ageing management. Since each RR is unique in design and operation, the degradation phenomena are unique in each reactor. SERAMIS is more suitable for RR, especially for the Shielding Experimental Reactor at Tsinghua University. Compared with COMSY, SERAMIS keeps a wide range of records related to ageing management, including videos, photos of aged SSCs, safety regulations, and IAEA documentations. This is helpful for users to make a comprehensive analysis on reactor ageing. Moreover, SERAMIS is based on B/S architecture programming, which is easy to maintain and extend. SERAMIS is a preliminary exploration of MIS for the Shielding Experimental Reactor ageing management. Future work is needed in the following aspects. Firstly, more specific investigation of demands from ageing management should be carried out to improve SERAMIS. For example, as IAEA documents do not provide specific criteria for a particular RR, we need to figure out more acceptance or safety criteria and enter them into SERAMIS. With these criteria, we can effectively diagnose ageing phenomena. Secondly, robust capability of data processing is needed for knowledge discovery and decision-making. Ageing management
covers the whole lifecycle of the reactor, with data continually accumulated. Advanced data processing techniques, such as data warehouse (Inmon, 2005) and data mining (Han and Kamber, 2006), will be applied to large-quantity multi-source information fusion in ageing management areas. In this way, useful information will be extracted for ageing trend analysis and cable diagnosis, drawing ideas from Gulski et al. (2003) and Peres et al. (2007). From programming perspective, in order to avoid unexpected failure due to diverse clients’ environments, complicated computation of data will be implemented by server-side Java program rather than client-side JavaScript program. Thirdly, the four modules structure (Guidelines, SSCs records, Service conditions and environment, and IAEA documents) would better be expanded to five modules. In the current version of SERAMIS, each module has its own assessment and analysis package. But there is not an independent module that works for inter-module analysis. It may be a good idea to build an “Assessment and Analysis Module” to aggregate the data from the four modules above and perform overall analysis. Fourthly, enhancement of networking and security is needed. SERAMIS is generally guarded by Tsinghua intranet firewall from being maliciously attacked. Technically, it is not open to public users. To improve the network security, we will use Hypertext Transfer Protocol over Secure Socket Layer (HTTPs) instead of regular HTTP and encrypt classified information. In addition, some experts indicated that Tomcat itself is subject to multiple vulnerabilities, especially when communicating with MS SQL Server. To avoid unexpected accident and communication error, we take this issue seriously and will use a more robust application server instead of Tomcat. Acknowledgements The authors would like to express their sincere gratitude to the editors, reviewers, and faculty in the Reactor Operation Division and the Safety & Protection Department at the Institute of Nuclear and New Energy Technology (INET) of Tsinghua University.
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Appendix A. Nomenclature and abbreviations AMP ageing management program B/S browser/server C/S client/server DAO data access object DBMS database management system HTML hypertext markup language HTTP hypertext transfer protocol HTTPs hypertext transfer protocol over secure socket layer IAEA International Atomic Energy Agency INET Institute of Nuclear and New Energy Technology ISI in-service inspection J2EE Java2 Enterprise Edition JDBC Java database connectivity JSP Java server page MIS management information system MVC architecture Model-View-Controller architecture NPP nuclear power plant PSR periodic safety review RR research reactor s/mm second/millimeter SERAMIS Shielding Experimental Reactor Ageing Management Information System SQL structured query language SSCs systems, structures and components References Gulski, E., Quak, B., Wester, F.J., De Vries, F., Mayoral, M.B., 2003. Application of data mining techniques for power cable diagnosis. In: Proceedings of the IEEE International Conference on Properties and Applications of Dielectric Materials, vol. 3, pp. 986–989. Gulzar, N., 2003. Practical J2EE Application Architecture. McGraw-Hill/Osborne, Emeryville, pp. 165–201. Hakim, L., 2006. Safety Assessment for Regulation of Ageing Management on Nuclear Installation (PowerPoint form). IAEA EBP Asia-Regional Workshop on the Management of Research Reactors Ageing, Beijing.
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Design of a management information system for the Shielding Experimental Reactor ageing management Jie He ∗ , Xianhong Xu Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, PR China
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Article history: Received 21 June 2008 Received in revised form 26 August 2009 Accepted 9 October 2009
a b s t r a c t The problem of nuclear reactor ageing is a topic of increasing importance in nuclear safety recent years. Ageing management is usually implemented for reactors maintenance. In the practice, a large number of data and records need to be processed. However, there are few professional software applications that aid reactor ageing management, especially for research reactors. This paper introduces the design of a new web-based management information system (MIS), named the Shielding Experimental Reactor Ageing Management Information System (SERAMIS). It is an auxiliary means that helps to collect data, keep records, and retrieve information for a research reactor ageing management. The Java2 Enterprise Edition (J2EE) and network database techniques, such as three-tiered model, Model-View-Controller architecture, transaction-oriented operations, and JavaScript techniques, are used in the development of this system. The functionalities of the application cover periodic safety review (PSR), regulatory references, data inspection, and SSCs classification according to ageing management methodology. Data and examples are presented to demonstrate the functionalities. For future work, techniques of data mining will be employed to support decision-making. © 2009 Elsevier B.V. All rights reserved.
1. Introduction The International Atomic Energy Agency (IAEA), defines reactor ageing as a general process in which characteristics of systems, structures and components (SSCs) gradually change with time or use (IAEA, 1995). This process eventually leads to degradation of materials and components subjected to normal service conditions. Without preventive measures, ageing can result in equipment and component failures. In order to ensure safety and reliability of continued operation, it is very important to implement ageing management programs (AMPs) for reactors. A number of authoritative articles have indicated the significance and necessity of software tools in reactor ageing management. IAEA (1991) indicates how to classify data related to ageing management and manage them efficiently. Computers are recommended to help process the data involved in ageing management. In that article, data are classified into three categories, i.e. baseline information, operating history data, and maintenance history data. IAEA (1999, 2003a, 2004a,b) indicate that database applications and database management system (DBMS) along with other hardware and software can serve as engineering tools for operation and ageing management. Furthermore, at a workshop of IAEA, data collection and record keeping is noted as one of the
∗ Corresponding author. Tel.: +1 919 455 3879. E-mail address: [email protected] (J. He). 0029-5493/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.nucengdes.2009.10.017
key issues in an ageing management program (Hakim, 2006). These works have demonstrated the importance of database applications to reactor ageing management but do not elaborate how to design and implement a software system. Helmut et al. (2006) introduces the AREVA’s software tool COMSY for ageing management, but this is for reactors in nuclear power plants (NPPs), rather than research reactors. Xinjun et al. (2005) introduces database systems used for research reactor operation management. The systems are helpful to data collection and storage, but the systems are not professional for ageing management use. In fact, there are few professional software systems developed for reactor ageing management around the world, especially for research reactors. The Shielding Experimental Reactor (Fig. 1) at Tshinghua University is a twin-core pool type research reactor (RR), which was commissioned in 1964. Ageing management has been implemented since early-1980s, with the documentation being processed manually without computer aids. This paper presents pioneering work in MIS development for the Shielding Experimental Reactor, which sets an example to general research reactors ageing management. An ‘MIS’ is a planned system of the collecting, processing, storing and disseminating data in the form of information needed to carry out the functions of management. The authors of this paper recently developed the MIS based on a browser/server (B/S) mode by J2EE. This is a part of the studies on the Shielding Experimental Reactor ageing management. The objective of the applications is to support the ageing management program. Our presentation (He, 2006) talked about the design of the system at the IAEA workshop
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Fig. 1. Exterior of the Shielding Experimental Reactor.
at Tsinghua University 2006. Some design ideas of this MIS are taken from the participants’ presentations at that workshop. This paper first reviews the background of the reactor ageing management program. Then, the architecture of the SERAMIS modules is introduced, including the elaboration of the programming of J2EE technology. In particular, several primary functions of this system are presented to show how they meet the demands of ageing management regulations and practice. For further clarity, some examples are given. Conclusions and future work are discussed by the end. 2. Software design criteria In the practice of reactor ageing management, safety-related work requires systematic, strict, and specialized studies. Software should also meet this requirement. IAEA (2005) proposes software to be included into reactor safety management as well as important SSCs. Therefore, how well this software tool applies to the methodology of nuclear safety management is important. Another objective of the MIS lies in data inspection and analysis. We need to process observations from periodic inspections to analyze ageing and environmental impacts. Robust capability of data processing is our goal. Generally, we try to make the MIS meet the following basic requirements: • Software itself should be safe and secure. • Data security should be ensured. • Both reactor SSCs and environmental monitoring should be included. • SSCs are classified according to regulations. • Abnormal observations can be preliminarily detected by embedded inspectors. • The system is equipped with basic statistical tools for ageing analysis. • User access control and human factors are taken into consideration.
• Accessing the system is convenient and its interfaces are userfriendly. Since SERAMIS development is ongoing, these requirements may be insufficient, and improvements are anticipated. 3. Modules in SERAMIS After login, users reach the menu of SERAMIS. Users can choose out of the four modules by clicking the buttons on the left. The four modules are: Guidelines, SSCs records, Service conditions and environment, and IAEA documentations. The structured data of the modules are stored in relational databases, managed by MS SQL Server. The Guidelines module provides users with the introductions to reactor ageing management, the summary of Shielding Experimental Reactor (Fig. 2), and the ageing management programs. The module directs users to implement AMPs of this reactor. The SSCs records module manages the data of SSCs important to safety. These data include baseline information, operating history data, and maintenance history data mentioned in IAEA (1991). The majority of these data are PSR records. The PSR is not only defined as the overall assessment of the whole reactor every 10 years (IAEA, 2003b), but also specific to every component reviewed at shorter intervals. We implement periodic testing according to IAEA (2006) and store results via this module. Besides numerical data, the photos and videos of visible ageing features (for example, the change of color, shape, and the appearance of cracks and corrosion spots) are also kept in the system (Fig. 3). The module of Service conditions and environment helps to monitor the condition of SSCs, ageing and safety performance of the reactor, and its radiological impact on the environment (IAEA, 2005). The service conditions are what affect material properties or functional capabilities, or lead to obsolescence and affect reactor safety (IAEA, 1995). The IAEA documentations module is a collection of safety guides and series related to ageing management. Since IAEA plays a key
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Fig. 2. A user interface in the ‘Guidelines’ module of SERAMIS showing the introduction to the Shielding Experimental Reactor.
Fig. 3. A user interface in the ‘SSCs records’ module of SERAMIS showing a photo of corrosion on the inner surface of the pool tank.
role in the global nuclear field, its documentations have authoritative weight. The AMPs of our reactor follow these guides. This module provides convenient references for users to download them or read online. Entered into SERAMIS, data are stored in relational databases. All of the four modules allow for operations of insertion, deletion, updating, and query on data by the users who are granted permission. Questionable or abnormal data can be detected by an automatic inspector to warn users to make a further diagnosis. Statistical graphs are available for data analysis. The overview of the SERAMIS modules is shown in Fig. 4. 4. Programming implementation SERAMIS is based on browser/server (B/S) mode. This mode allows the user access the server with identified username and password from wherever an internet connection is available. There is no need to install any client-side software.
The applications were programmed by Java, HTML, and JavaScript, attached to MS SQL Server via JDBC. The J2EE web technology is important to the development of SERAMIS. J2EE is a Java2 Enterprise Edition developed by Sun Microsystems. The J2EE applications provide platform independence, easy access of users, and global communication among engineering team members located dispersedly (Huang et al., 2004). HTML stands for Hypertext Markup Language and is widely used on the World Wide Web. It describes the text, images, and other objects in web pages. HTML files with Java tags embedded in are called Java server page (JSP) files. JSPs are compiled by the web server and output to HTML for user browsing. The web browser (e.g. Microsoft Internet Explorer) is the tool to interpret HTML. JavaScript (developed by Netscape) is a client-side object-based scripting language, which can be included on web pages to make them more interactive. A Java database connectivity (JDBC) is needed to provide a set of Java classes and interfaces so that Java server programs can access DBMS.
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Fig. 4. Scheme of the architecture of SERAMIS.
The following are representative programming techniques used in SERAMIS development. Some of them are for the consideration of system reliability and stability. 4.1. Three-tiered model From a programming aspect, SERAMIS consists of three tiers, i.e. the presentation tier, middle tier, and database tier (Fig. 5). This is the typical architecture of the B/S mode. In presentation tier, the applications render the user interface in HTML. Users access SERAMIS like browsing web pages from a website. The middle tier is also called business logic tier. In this tier, the server components are stored on a web server—Tomcat. It serves as a container. A servlet is a Java program that runs in this container. Typically, the servlet receives an hypertext transfer protocol (HTTP) request from a browser, generates dynamic content (such as by querying a database), and provides an HTTP response
back to the browser. Servlets or JSPs invoke the public methods in data access objects (DAOs) to access databases through the JDBC driver. In database tier, MS SQL Server manages all the data stored on hard disks and provides ports for the middle tie accessing. Compared with the two-tiered client/server (C/S) model, developers of three-tier do not have to develop and update client-side applications considering clients’ complex environments. 4.2. Model-View-Controller architecture In the presentation and middle tiers, the application components are developed following the pattern of Model-ViewController (MVC). The MVC architecture is a way of decomposing the application components into three parts: the Model, the View, and the Controller (Gulzar, 2003). A Model is in charge of accessing and manipulating database usually by SQL. The View is to forward user input to the Controller and present the outcomes of Model
Fig. 5. Browser accessing data through the SERAMIS’s three tier.
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to users. The Controller is the intermediate between the View and Model, translating user input into actions to be performed by the Model. As for SERAMIS, HTML files and JSPs compose the ‘View’; servlets act as ‘Controller’; DAOs belong to ‘Model’. In MVC architecture, the three parts are developed independently and functional programs are specified separately. In this case, Software framework and component reuse becomes easy. The reuse can enhance the efficiency of software development, offer clear responsibilities between web page designers and software developers, and improve system maintainability and extensibility (Li et al., 2006). 4.3. Transaction-oriented database operations A transaction is a short sequence of operations with the database which represents one meaningful activity in the users’ environment. It is treated as a logical unit of work that cannot be divided into pieces with respect to concurrency and recovery. We adopt this technology in order to avoid data inconsistency caused by unexpected accidents. For example, we are going to update the records of a reactor component in the database. There are two tables storing the data related to this component, which means both of them need to be updated. Computer executes the operations on the two tables one after another. However, without transaction-oriented programming, if the system happens to break down after the operation on the first table, the operations on the second table may not be executed successfully. As a result, data inconsistency occurs: data in the first table are updated but data in the second table are not. This may cause contradiction in ageing management. To avoid this exception, we widely use the following Java code for database operations: conn.setAutoCommit(false) and conn.commit(). These two statements can effectively prevent data inconsistency. Every single statement between the two statements cannot be submitted unless all of the statements are executed successfully because they are considered a logical unit of work—transaction. Data consistency is guaranteed. 4.4. JavaScript programs Structured data management requires data be in proper format before entered into database. In SERAMIS development JavaScript is mainly used for input verification and data inspection. Since JavaScript is a client-side language that can be interpreted by the browser, it is much easier to verify the input data by JavaScript programs than by server-side languages. In addition, detecting questionable or abnormal data with ageing criteria can also be easily implemented by JavaScript programs. In case that JavaScript requires proper environments on clients’ computers, for complicated data mining, server-side programming (e.g. JSP) will be considered to process data, instead of JavaScript.
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ageing effect on a certain SSCs may become more important than before. This situation calls for renewed criteria, frequent tests, and periodic safety reviews (Myung et al., 2004; Winfield, 2006). Therefore, it is necessary to continually update these records. For this purpose, SERAMIS has the functionality of reminding users to regularly update the data and files. Ageing criteria and observations are marked with time when created in the systems. The user is asked to denote a period of validity (e.g. how many months or years) or inspection frequency (e.g. weekly, annually, or 5 yearly) for them. When it is approaching the expiration, the system proposes notification on reinvestigation. Updated criteria observations are marked with new date. This function serves as a safeguard so that out-of-date records are not used for decision-making. 5.2. Data inspection To discover potential ageing problems, it is necessary to detect abnormal data from observations, according to technical standards. After retrieving data from the database, the system can be requested to inspect the data to see whether or not the observation values meet the safety criteria specified by users. Abnormal data will be colored as a warning. This process can be completed by embedded programs of JavaScript. The following paragraphs introduce an example that how SERAMIS helps us to detect questionable data of electrical cables on reactor devices. The ageing management of cables is important to a reactor, which is particularly introduced by IAEA technical documents (IAEA, 1997, 2000). Electrical cables on reactor devices are exposed to various environmental conditions (physical/chemical), such as temperature, water vapor, or ionizing radiation, etc. These environmental service conditions induce ageing processes at the molecular level of the materials. Loss of cable functionality is usually determined by the changes in mechanical properties, cracking of the insulation preceding electrical failure (i.e. loss of insulation resistance) (IAEA, 2000). As for the Shielding Experimental Reactor, changes of electrical properties on the cables in long-term service may cause degradation in the functional characteristics. To diagnose the degradation, periodic inspections on cables are carried out at the interval of 1 or 2 years. Fig. 6 shows detected electric resistance of the insulating layers on cables. The ageing features of a cable mainly lie in the degradation of its insulating materials. In this table, the letters A, B, and C, respectively, represent the wires of the three phases wrapped in one cable. Cells with missing data are colored in grey. Abnormal data are defined as the following criteria. • The safety limit is assumed as r0 M. If a resistance value is below it, i.e.: r < r0 the table cell containing it appears pink. • Although environment conditions can result in slight fluctuations in observations, large differences between consecutive yearly observations of the same item are questionable. We consider:
5. Functionalities of SERAMIS Besides data storage, other functionalities are also developed in light of ageing management methodology. 5.1. Reminder for PSR data updates As the operating conditions gradually change with time or use, the trends and inducements of ageing often change as well. Some
|rn+1 − rn | > rt to be abnormal. The rn and rn+1 represent the resistance observed by consecutive detections, and rt represents the acceptable maximum difference. Consecutive observations that fluctuate sharply are colored blue. • As time goes by, only monotonic drop of resistance is considered reasonable. Table cells containing increasing resistance
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Fig. 6. PSR data of the resistance of insulating layers on cables for electrical equipments, with questionable observations automatically colored by SERAMIS as a warning (unit: megaohm).
data, i.e.: rn < rn+1 are colored yellow. The subscript ‘n’ and ‘n + 1’ represent consecutive yearly detections. The parameters can be defined and refined by users according to specific circumstances. Fig. 7 shows the user interface for specifying the criteria. Users are allowed to set any of the three criteria by checking off the boxes and filling in values for thresholds. In this example, we let: r0 = 5 megaohm rt = 100 megaohm. Questionable data in Fig. 6 are colored for distinction. 5.3. Assistance with SSCs classification SERAMIS helps with the classification management of SSCs according to IAEA (1995, 2005). There are no more than a dozen ageing mechanisms that cause thousands of SSCs ageing in reactor
SSCs. In most cases, ageing problems on similar SSCs are often analyzed synthetically. Meanwhile, technical and financial problems should also be taken into consideration if we want to modify or replace a component. So, it is necessary to classify SSCs into categories regarding the similarities in ageing management among them. Table 1 shows some of the classified SSCs of the Shielding Experimental Reactor with the abbreviations explained in Table 2. In SERAMIS, 12 frequent mechanisms of SSCs ageing, such as Corrosion, Radiation, Temperature, Pressure, etc., are listed for selection. Since ageing is often caused by two or more mechanisms jointly, one or two most important mechanisms are picked out as ‘principal ageing mechanism’ to highlight its ageing features. Meanwhile, SERAMIS rates the ease of SSCs replacement into four levels, namely, No, Difficult, Normal, and Readily. This property is designated by experts. The replacement difficulty of the same component may vary from case to case, depending on where it is installed and its environments. For example, the replacement of cables for accessory devices is not as difficult as that for in-core equipments. Such components are usually noted with two different ease rates. Experts are asked to denote the rates when entering SSCs records into the system. When working on a refurbishment program of SSCs, SERAMIS
Fig. 7. An interface of user-defined criteria of abnormal data for automatic inspection.
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Table 1 List of the Shielding Experimental Reactor systems concerning their importance to safety and replacement ease. Items
Safety related
Replacement ease
Ageing mechanisms
Predominant ageing mechanisms
Beam tubes Biological shielding Cables Communication Control rods/mechanisms Control systems Crane Fire protection Fuel elements/storage Measuring instrumentations Pool internals Primary cooling systems Protection systems Purification systems Radiation monitoring systems Reflector Secondary cooling systems Shutdown systems Signal devices Tank UPS systems Water supply systems
Y Y M M Y Y M Y Y M Y M Y M Y Y N Y Y Y Y N
A/B A B/C C/D C C B/C B C C B B/C B C C C C C C A B/C C
3,5,12 1,2,3,4,5 1,2,5,12 5,12 1,4,5,12 2,4,6,12 4,5,12 5,12 1,2,5 1,2,4,6,12 1,4,5,6,7 1,4,5,6,7,12 4,5,12 1,2,5,12 5,12 1,4,5,12 4,5,6,7,12 4,5,12 2,4,6,12 1,2,4,5,6,12 5,6,12 5,12
5 1,5 12 12 12 12 12 12 1,5 12 1,5 7 12 12 12 12 12 12 12 5 12 12
Table 2 Abbreviations.
5.6. Basic statistical analysis
Safety related
Replacement ease
Mechanisms
Y—Yes N—No M—Maybe
A—No B—Difficult (tech. or costly) C—Normal D—Readily
1—Radiation 2—Temperature 3—Pressure 4—Cycling 5—Corrosion 6—Chemical 7—Erosion 8—Technology changes 9—Safety requirements 10—Documentation 11—Human factors 12—Design/operation/ maintenance
users can inquire about the ageing mechanism and replacement difficulty.
Statistical analysis reveals data characteristics from the observations, and displays them on web pages. The calculation is performed in the middle tier by mathematical functions of the system. The frequently used statistical parameters are sum, mean, mode, maximum, minimum, and deviation. As an example, Tables 3 and 4 show measurements of the yearly PSR of the six control rods withdrawal and scramming velocity. The velocity of rods rising and dropping is measured in terms of ‘second/millimeter’ (s/mm). We measured the time consumption while a safety rod rises or drops across the whole altitude of 600 mm for emergency shutdown, and while automatic or manual rods move up or down across 100 mm to control the reactor power. In Fig. 8, the plots of the yearly measurements of manual rods from Table 4 are joined by line segments. From the graphs we can see the measurements are nearly constant and manual rods are not seriously ageing during the period from 1996 to 2004. The functionality of statistical analysis makes it easier for users to perceive the observations.
5.4. User access control In order to enhance security and clarify commitment, different users are given their unique authority that restricts the scope of access to the data, AMPs, and regulations. The system also distinguishes different users’ roles in ageing management. As an example, for modification permission, only safety committee or experts are qualified to revise them. Users are merely entitled to read the records related to their work rather than revise any records, unless they are granted to do so. 5.5. Guides according to AMPs and regulations Since ageing management is involved in the safety of nuclear reactor, most activities (e.g. SSCs replacement or modification) must obey AMPs and regulations. There are introductions to the activities in SERAMIS, such as in-service inspection (ISI), assessment, and preventive maintenance. Users can consult the introductions when implementing AMPs so that operations can progress methodically. Moreover, special tests or modifications are highlighted to ensure modifications on the facilities are approved by safety committee and regulators (if required) prior to implementation (Winfield, 2006). Unlicensed modifications are not acceptable.
Fig. 8. Plots and fitted lines of the yearly measurements of the safety rods and automatic rod dropping velocity.
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Table 3 Periodic test results of the velocity of safety rods and automatic rod rising/dropping of core 2. Test date
2004/06 2003/06 2002/06 2001/06 2000/06 1999/06 1998/06 1997/06 1996/12
Safety rod 1#
Safety rod 2#
Automatic rod
Rising (s/600 mm)
Dropping (s/600 mm)
Rising (s/600 mm)
Dropping (s/600 mm)
Rising (s/100 mm)
Dropping (s/100 mm)
18.41 16.25 19.54 18.29 18.92 18.84 23.38 18.43 22.82
0.72 0.66 0.67 1.00 0.85 0.48 0.67 0.69 0.76
20.09 17.65 20.15 18.13 20.21 20.78 22.04 18.37 22.26
0.79 0.77 0.65 0.99 0.70 0.45 0.63 0.54 0.50
24.58 23.49 22.89 23.77 26.23 25.57 27.67 21.06 25.46
1.88 1.95 1.89 1.67 1.93 1.59 2.13 1.94 1.69
Table 4 Periodic test results of the velocity of manual control rods rising/dropping of core 2. Test date
2004/06 2003/06 2002/06 2001/06 2000/06 1999/06 1998/06 1997/06 1996/12
Manual rod 1#
Manual rod 2#
Manual rod 3#
Rising (s/100 mm)
Dropping (s/100 mm)
Rising (s/100 mm)
Dropping (s/100 mm)
Rising (s/100 mm)
Dropping (s/100 mm)
30.58 28.55 30.05 29.11 29.92 29.54 30.71 28.88 28.96
27.88 28.55 28.34 27.29 28.77 28.44 29.55 26.51 26.00
30.90 28.08 30.22 29.63 30.17 28.22 29.64 27.58 28.16
26.90 27.30 27.98 27.88 27.93 27.22 28.53 25.31 26.00
34.21 27.06 27.56 26.34 27.32 27.06 28.90 26.41 26.21
28.34 28.11 28.03 27.80 29.40 28.53 30.12 28.78 28.00
Currently, the SERAMIS has only elementary functionalities for statistics. In the near future we will improve this part. 6. Conclusions and future work This paper sets a generic example of MIS affiliated with reactor ageing management in nuclear industry. SERAMIS development is a multidisciplinary task, drawing work from nuclear engineering, computer science, and statistics. We try to design a helpful MIS causing the ageing management, procedure, and operation to take on its desirable configuration in efficient way. In this case, a minimum of economic cost and maximum of safety control can be achieved. As a reference, AREVA’s software tool COMSY (Helmut et al., 2006) is a very useful software tool for NPP ageing trend analysis, especially on pressure pipes and vessels ageing. In these aspects, COMSY is more functional than SERAMIS. Nevertheless, SERAMIS has some other advantages in RR ageing management. Since each RR is unique in design and operation, the degradation phenomena are unique in each reactor. SERAMIS is more suitable for RR, especially for the Shielding Experimental Reactor at Tsinghua University. Compared with COMSY, SERAMIS keeps a wide range of records related to ageing management, including videos, photos of aged SSCs, safety regulations, and IAEA documentations. This is helpful for users to make a comprehensive analysis on reactor ageing. Moreover, SERAMIS is based on B/S architecture programming, which is easy to maintain and extend. SERAMIS is a preliminary exploration of MIS for the Shielding Experimental Reactor ageing management. Future work is needed in the following aspects. Firstly, more specific investigation of demands from ageing management should be carried out to improve SERAMIS. For example, as IAEA documents do not provide specific criteria for a particular RR, we need to figure out more acceptance or safety criteria and enter them into SERAMIS. With these criteria, we can effectively diagnose ageing phenomena. Secondly, robust capability of data processing is needed for knowledge discovery and decision-making. Ageing management
covers the whole lifecycle of the reactor, with data continually accumulated. Advanced data processing techniques, such as data warehouse (Inmon, 2005) and data mining (Han and Kamber, 2006), will be applied to large-quantity multi-source information fusion in ageing management areas. In this way, useful information will be extracted for ageing trend analysis and cable diagnosis, drawing ideas from Gulski et al. (2003) and Peres et al. (2007). From programming perspective, in order to avoid unexpected failure due to diverse clients’ environments, complicated computation of data will be implemented by server-side Java program rather than client-side JavaScript program. Thirdly, the four modules structure (Guidelines, SSCs records, Service conditions and environment, and IAEA documents) would better be expanded to five modules. In the current version of SERAMIS, each module has its own assessment and analysis package. But there is not an independent module that works for inter-module analysis. It may be a good idea to build an “Assessment and Analysis Module” to aggregate the data from the four modules above and perform overall analysis. Fourthly, enhancement of networking and security is needed. SERAMIS is generally guarded by Tsinghua intranet firewall from being maliciously attacked. Technically, it is not open to public users. To improve the network security, we will use Hypertext Transfer Protocol over Secure Socket Layer (HTTPs) instead of regular HTTP and encrypt classified information. In addition, some experts indicated that Tomcat itself is subject to multiple vulnerabilities, especially when communicating with MS SQL Server. To avoid unexpected accident and communication error, we take this issue seriously and will use a more robust application server instead of Tomcat. Acknowledgements The authors would like to express their sincere gratitude to the editors, reviewers, and faculty in the Reactor Operation Division and the Safety & Protection Department at the Institute of Nuclear and New Energy Technology (INET) of Tsinghua University.
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Appendix A. Nomenclature and abbreviations AMP ageing management program B/S browser/server C/S client/server DAO data access object DBMS database management system HTML hypertext markup language HTTP hypertext transfer protocol HTTPs hypertext transfer protocol over secure socket layer IAEA International Atomic Energy Agency INET Institute of Nuclear and New Energy Technology ISI in-service inspection J2EE Java2 Enterprise Edition JDBC Java database connectivity JSP Java server page MIS management information system MVC architecture Model-View-Controller architecture NPP nuclear power plant PSR periodic safety review RR research reactor s/mm second/millimeter SERAMIS Shielding Experimental Reactor Ageing Management Information System SQL structured query language SSCs systems, structures and components References Gulski, E., Quak, B., Wester, F.J., De Vries, F., Mayoral, M.B., 2003. Application of data mining techniques for power cable diagnosis. In: Proceedings of the IEEE International Conference on Properties and Applications of Dielectric Materials, vol. 3, pp. 986–989. Gulzar, N., 2003. Practical J2EE Application Architecture. McGraw-Hill/Osborne, Emeryville, pp. 165–201. Hakim, L., 2006. Safety Assessment for Regulation of Ageing Management on Nuclear Installation (PowerPoint form). IAEA EBP Asia-Regional Workshop on the Management of Research Reactors Ageing, Beijing.
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