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ICIT activities related to tritium management
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ICIT activities related to tritium management Marius Zamfirache ∗ , Anisia Bornea, Ioan Stefanescu, George Ana, Liviu Stefan National Research and Development Institute for Cryogenics and Isotopic Technologies—ICIT, Rm. Valcea, Romania
h i g h l i g h t s • We present the main directions of ICIT research in the field of hydrogen isotopes. • Tritium Removal Facility became a nuclear installation. • ICIT had begun the transfer of detritiation technology.
a r t i c l e
i n f o
Article history: Received 27 July 2015 Received in revised form 2 February 2016 Accepted 8 February 2016 Available online xxx Keywords: Heavy water Detritiation Tritium Cryogenics
a b s t r a c t National Research and Development Institute for Cryogenics and Isotopic Technologies (ICIT) was established in 1970 as a research focused Industrial Pilot Plant. This new Institute was created with the purpose to develop the heavy water production technology. This technology has been successfully transferred to the heavy water production plant in 1988 (with a capacity of 360 t/year). Currently, research within ICIT is focused on the following main objectives: support for the National Nuclear Program, hydrogen and fuel cells, cryogenics, environment. Within ICIT it has been built an Experimental Pilot Plant having as the main objective the development of a technology for heavy water detritiation. The purpose of this Pilot Plant is to obtain technological data and functional characteristics of specific equipment in order to design a Detritiation Facility used for Nuclear Power Plants with CANDU reactors. This work is focused on the presentation of ICIT research activities, perspectives and its capability related to water detritiation technologies and also to on issues in the field of nuclear fusion. © 2016 Elsevier B.V. All rights reserved.
1. Introduction ICIT activity has its origins in the isotope research related to the development of heavy water production technologies in Romania in the 70 s. After this task was accomplished (heavy water plant was built and operating since 1988), research and development was oriented to a new field of isotope technology and applications. The main direction of the current experimental research it focuses on studying the hydrogen isotopes and cryogenic fluids, within an experimental pilot plant for deuterium and tritium separation. These studies are possible because Institute’s staff has a tradition of fundamental aspects research of isotopes physics and chemistry, including all phases from analysis and separation methods. According to the strategy and energy policy of our country, nuclear power has an important role in satisfying the electricity demand. Because the technology used within the nuclear power
∗ Corresponding author. Fax: +40 250732746. E-mail address: marius.zamfi[email protected] (M. Zamfirache).
plant is based on CANDU type reactors, the tritium issue became very important. Details regarding ICIT activities in the field of tritium management are described further. 2. ICIT current strategy This chapter shows the main directions of Institute’s research and development in the field of hydrogen isotopes, in particularly for tritium. 2.1. Tritium Removal Facility The main department within the Institute is represented by the Tritium Removal Facility (TRF). The TRF is actually an Experimental Pilot Plant for deuterium and tritium separation. From design to present configuration, several stages have been taken. This installation project was started in 1992 as a semi-industrial plant, aiming hydrogen isotopes separation and using “Liquid Phase Catalytic Exchange–Cryogenic Distillation” process (LPCE–CD).
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Fig. 1. TRF block diagram.
Table 1 TRF main data.
2.2. Fusion related activities
Water flow rate
5 kg/h
Detritiation factor LPCE CD Tritium storage Tritium inventory (total) Hydrogen inventory Heavy water inventory Vapor recovery HVAC
3 1 LPCE column: Ø100 mm Helium refrigerator 1000 W, 4CD columns cascade 1 titanium ITC 1 uranium ITC 7g 15 m3 200 kg (max. 30 Ci/kg) min. 100 m3 /h 10 exchanges/h
The building was finalized in 1997 as a chemical plant, with the express purpose to provide technical support for achieving heavy water detritiation technology. There followed three years of tests and experiments until 2000 (on this configuration were completed experiments on heavy water between a wide range of concentrations and also with low tritiated water), when it started the transformation of the chemical plant into a nuclear plant. Since 2002, the plant became an Authorized Nuclear facility, in accordance with national legislation. In 2009 was brought to the plant a barrel with 200 kg of tritiated heavy water. The main changes made to the installation consisted both in terms of nuclear safety (i.e. design of safety and safety related systems, developing of commissioning and operation procedures for a nuclear facility) and technical project (i.e. upgrading of refrigeration power, improvement of LPCE catalytic package). Nowadays, we are at the pre-operational phase and foreseen that at the end of 2016 the TRF will be under normal operating conditions. The purpose of TRF is mainly to confirm the technological data and the functional characteristics of the equipments, with the final objective of designing the detritiation of heavy water facility used in CANDU reactors. Also, the facility can be used for specific studies and experiments for detritiation systems used for fusion reactors like JET and ITER. The main characteristics of the TRF are presented in Table 1.
Our Institute participated at the research and development program within ITER related to several topics, as following: 2.2.1. Tritium Plant Consortium of Associates (TriPla–CA) • A consortium of 4 EU laboratories (KIT- the leading organization, ICIT, ENEA, CEA) to support tritium activities for ITER; • TriPla-CA will benefit from the results of experiments conducted on TRF. 2.2.2. Water Detritiation System (WDS) • Developing of Process Flow Diagram and Process and Instrumentation Diagram; • Providing support for the developing of HAZOP study, followed by implementation into design of its recommendations; • Participate in the review of the WDS design; • Detailed design of WDS tritiated water holding tanks including ANSYS Static & Dynamic Analysis in ASME III, Appendix N-Dynamic Analysis. 2.2.3. Highly Tritiated Water (HTW) • Developing of Process Flow Diagram based on PERMCAT and Vapor Phase Catalytic Exchange (VPCE) technologies; • Process modeling for VPCE module within HTW system, followed by simulation in order to obtained data for design; • Participate at developing of HAZOP study for the HTW; • Feasibility study of proposed technology diagram. 2.3. Tritium analysis and environment There are two ways that Cryogenic Pilot can interact with the environment: by atmospheric release and by sewage. The tritium quantity estimated to be released by gaseous effluents is around 7.4 × 1012 Bq/year. Until now, the testing of the processes was made with heavy water, and tritiated water below the 103 Bq/kg tritium concentrations, which fulfills the exempting level from the Romanian National Regulations for nuclear facilities.
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Fig. 2. Cryogenic distillation Cold-box.
Tritium Laboratory has two main tasks: to determine tritium level during the operation of TRF, in processed tritiated heavy water, and to evaluate tritium level in the surrounding environment of the nuclear facility. This laboratory has two operational units due to the wide range of tritium radioactivity; one dedicated to the high tritium radioactivity for different samples of TRF process fluid, tritiated water leakage, tritiated effluents, and the other is dedicated to low level tritium radioactivity for the environmental samples around TRF, and for biological samples (urine), which is needed for assessing the personnel internal dose. The method used in this laboratory is liquid scintillation method, each unit having an appropriate type of liquid scintillation spectrometer: TRICARB 2800 TR (PerkinElmer) for high tritium radioactivity, and two Quantulus 1220 (PerkinElmer) for environmental tritium radioactivity [1]. Particular attention is paid to the sample preparation for LSC measurement [2]. If the process fluid of TRF is usually water, the environmental samples have a large variety: air, water, soil, homegrown products. Knowing the tritium hygroscopic property, tritiated water (HTO) is easily incorporated into biological organisms as tissue free water tritium (TFWT). Once into the tissue, tritium may label organic matter as organically bound tritium (OBT) through biological processes. Tritium level has been determined in the water extracted from environmental samples collected around
TRF [3]. OBT measurement is another type of measurement optimized for the laboratory existing equipment [4]. The Institute laboratories are designated as laboratories advised by National Committee for the Control of Nuclear Activity (CNCAN) with the Advise No. ICSI LI-01/2013, which is valid until 17 January 2016 for the measurements of high and environmental tritium activity, gamma analyses and global alpha-beta low activity sampling. The practice and specific measurement procedures developed within the laboratory were confirmed by the results obtained in the “Proficiency Test Inter-comparison Exercises” organized by the International Atomic Energy Agency Vienna, first participation being in 2000 (Sixth IAEA Inter-comparison of LowLevel Tritium Measurements in Water—TRIC2000) [5]. Other type of inter-comparison in which Tritium Laboratory was involved were: National Physical Laboratory–Teddington (Environmental Proficiecy Test Exercise 2008) and the bilateral competence testing with the Slovenian Laboratory for Liquid Scintillation Spectrometry at the Department of Low and Medium Energy Physics, from Josef Stefan Institute [6]. Tritium working group of Comissariat a l’Energie Atomique et aux Energie Alternative (CEA–EA) and Atomic Energy Canada Limited (AECL) organized an international task group on environmental OBT analysis. Tritium Laboratory participated to their intercomparison exercises and workshops, the obtained results for
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different types of sample (potatoes, sediments and wheat) not only confirming the measurement procedure, but also requiring new improvements of sample preparation procedures [7]. Tritium Laboratory was involved in different research projects, tritium level in the environment being one of the main objective projects [8,9]. The expertise of measuring low levels of tritium in the environment using LSC direct measurement without electrolytic enrichment allows to Tritium Laboratory to process large numbers of samples, essential in any monitoring program, especially of nuclear fusion facility. 3. Tritium separation technology 3.1. TRF, present status The present status of TRF it can be summarized as following characteristics (the block diagram of TRF is shown in Fig. 1): • • • • • •
Licensed for construction for 30 g tritium; Licensed for commissioning for low tritium level—initial start; Tritium on site—200 kg DTO from NPP Cernavoda; Work procedures and equipment upgrading for facility; Tritium laboratory notification; Environmental laboratory notification.
The improvements were made to the installation capacity and to the process itself in order to achieve the following objectives: • Increment of the tritium gas concentration which will be stored as metal hydride—this target will be attained mainly by increasing the refrigeration capacity to 1000 W. This upgrading also allow us to expand the range of process parameters and thus to diversify the experiments which could be done in the TRF (new cold-box shown in Fig. 2); • Introducing of improved catalytic packing into the LPCE column (the LPCE module within TRF presented in Fig. 3); • Improvement of the gas purification module; • Improvement of the isotope measurement system, both in liquid and gaseous phases (needed to certify the purity of the tritium stored and of the separation performances). 3.2. Technology transfer All the experience gained over the years within the ICIT–TRF [10] (which continues at the present days), allows us to realize the detritiation technology transfer towards NPP Cernavoda. The final objective of this transfer is the construction of Cernavoda Tritium Removal Facility (CTRF). The first stage of this technological transfer consisted in issuing and approval of the following two documents: pre-feasibility and feasibility study. The pre-feasibility study allowed us to choose the technology which will be used to the future CTRF. Starting from some basic data (i.e. detritiation factor, quantity of heavy water to be detritiated, the targeted tritium concentration) have been developed pre-conceptual design for several technological options [11]. For each option taken account, have been applied several criteria, each criterion having a weight depending on its relevance (some of the general criteria used to delimit the chosen option: minimum risk associated to personel and enviroment, operating safety, licensing, complexity, utilities cost, operating cost, overall cost). In our case, the chosen option was “Liquid Phase Catalytic Exchange–Cryogenic Distillation” (LPCE–CD). Within the feasibility study, among other information provided, we have developed conceptual design for main systems and also the
Fig. 3. LPCE module.
implementation schedule of the investment (including approvals, permits and authorizations needed). The next stage of the technological transfer was the developing of technical documentation for all systems that are part of the facility (CTRF), including safety systems, utilities, Instrumentation and Control, building. Initially as base for conceptual design, it was necessary to elaborate some documents which were used as design basis (these documents were made by our Institute staff and/or our collaborators like Kinectrics and Candesco from Canada, CITON from Romania). The documents which have been issued prior to the design phase were as following: • Authorization Framework (identify documents that will be issued to regulatory body for approval or informal, at different phases of the facility); • Safety Design Guide (provides of safety design requirements for the project, safety functions and identification of safety related systems); • Licensing Basis Document (define licensing requirements for the design, construction, operation and decommissioning of the facility); • System Classification List for Pressure Retaining Systems (list the equipments and systems in the facility and identifies the classification requirements of each according to the country’s pressure standard). There was also issued an initially safety analysis which provides a preliminary assessment of the location of the facility and the impact accidents will have on the NPP systems. Following the conceptual design was complete and includes: • Major process systems are full design;
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• Requirements for utilities and auxiliary systems; • Defining the interface with the station; • Control and safety systems philosophy and requirements. In addition, for authorization purpose were produces safety analysis for conceptual design and hydrogen behavior for CTRF. Major issues into design were considered:
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5. Conclusions One of the conclusions of this paper is to acknowledge the level of activities developed within the ICIT facility and to propose to be used as base for future projects, being the only plant of its kind at this moment that can be used either for research related to fusion (ITER) or for Tritium Removal Facilities. Results from ICIT TRF are summarized as follows:
• Location of the plant is near safety systems of the NPP, so CTRF has to be design to not affect safety operation of NPP; • Design basis earthquake was reconsider after Fukushima accident; • Tritiated water transfer by aerial double wall pipes issues; • Industrial accident (hydrogen explosion) to be consider as major event which affects the site and population (by doses to environmental).
• Process design and the facility itself based on last knowledge which permit the approach for engineering and experimental support for ITER; • Catalysts and packing for LPCE processes are fully developed and available; • Expertise for design and management for large scale TRF, referenced by CTRF project; • Operating information available, including tritium analysis and management.
As result new solutions were required into design. For hydrogen explosion event it was considered a Safe Shutdown State to limit the hydrogen inventory which contribute to an explosion who affects safety operation of NPP. During this stage there were multiple iterations, both with the beneficiary and the nuclear regulatory body. In summary, the status of the project is:
In terms of future development, ICIT consider tritium application for TRF as an actual R&D objective and therefore an important number of specialists within ICIT TRF are oriented to the major projects CTRF and ITER, assuming that in next ten years both will be constructed and expertise is required.
• Conceptual design approved; • Safety documentation for conceptual design with CNCAN (Romanian regulatory body) for approval.
Experience gained was made possible thanks to funding by the government research agency ANCSI and support provided by CNCAN (nuclear regulatory body), ISCIR (authority in the field of installation/equipment), CITON (design). Also, need to specify the productive collaboration with AECL (actual CANDU Energy), Kinectrics and Candesco (from Canada) and IS TECH (Romania). Not least, it should be mentioned the essential contribution of Tritium Removal Facility team.
The next phase of the CTRF project will be construction phase which will be developed as an turn-key project by an EPC type contract open for international biding. The current schedule shows that construction and commissioning of CTRF has to be ended up to 2022.
Acknowledgments
References 4. Management For ICIT the CTRF project (which includes TRF as support—technological transfer) is the major activity considered. From management point of view it is a medium project but as not to many nuclear project are developed in the world, specific requirements are needed. During the past phases from management point of view some issues were identified to be solved: • Lack of specialists for specific industrial level TRF (Pilot plant, CTRF); • Interfaces with authorities for both facilities, CTRF and pilot plant, as it is low experience related to authorizing framework for such plants in Romania; • Small number of suppliers of services for nuclear facilities in Romania, most of them located on Cernavoda site and not available for other projects most of the time; • Cost associated to nuclear facilities services. ICIT maintain the projects under control by developing own skills or using available specialists. However cost associated to nuclear activities produced delays for ICIT pilot plant as the institute is a state own company and authorization process by CNCAN is time consume affecting the scheduled activities.
[1] C. Varlam, et al., Applying direct liquid scintillation counting to low level tritium measurement, Appl. Radiat. Isot. 67 (5) (2009) 812–816. [2] C. Varlam, et al., Establishing routine procedure for environmental tritium concentration at ICIT, Rom. J. Phys. 56 (1–2) (2011) 233–239, ISSN: 121-146X. [3] C. Varlam, et al., Tritium monitoring in the environment at tritium separation facility–ICIT, Fusion Sci. Technol. 60 (3) (2011) 1002–1005, ISSN 1536-1005. [4] I. Vagner, C. Varlam, I. Faurescu, D. Faurescu, Organically bound tritium level in vegetation at ICIT tritium removal facility, J. Radioanal. Nucl. Chem. 303 (3) (2015) 2259–2263. [5] M. Gröning, C.B. Taylor, G. Winckler, R. Auer, H. Tatzber, Sixth IAEA Intercomparison of Low-Level Tritium Measurements in Water (TRIC2000) REPORT, Vienna, 2001, p. 43. http://www.naweb.iaea.org/napc/ih/documents/ IHL/TRIC/TRIC2000-Report.pdf. [6] D. Glavic-Cindro, C. Varlam, D. Faurescu, I. Vagner, J. Kozar-Logar, Slovenian–Romanian bilateral inter-comparison on tritium samples, Appl. Radiat. Isot. 87 (2014) 418–424. [7] C. Varlam, I. Vagner, I. Faurescu, D. Faurescu, Combustion water purification techniques influence on OBT analysis using liquid scintillation counting method, Fusion. Sci. Technol. 67 (3) (2015) 623–626. [8] C. Varlam, et al., Radiocarbon and tritium level along the Romanian lower Danube river, Radiocarbon 52 (2) (2010) 783–793. [9] C. Varlam, et al., Tritium activity concentration along the western shore of the Black Sea, J. Radioanal. Nucl. Chem. 298 (3) (2013) 1679–1683. [10] Marius Zamfirache, Liviu Stefan, Anisia Bornea, Ioan Stefanescu, Acquired experience resulting from transforming a chemical installation to a nuclear, Fusion Sci. Technol. 67 (3) (2015) 677–680. [11] Anisia Bornea, Marius Zamfirache, Liviu Stefan, Ioan Stefanescu—the prediction of tritium level reduction of NPP cernavoda using CTRF, Fusion Sci. Technol. 60 (4) (2011) 1411–1414.
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FUSION-8544; No. of Pages 5
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Contents lists available at ScienceDirect
Fusion Engineering and Design journal homepage: www.elsevier.com/locate/fusengdes
ICIT activities related to tritium management Marius Zamfirache ∗ , Anisia Bornea, Ioan Stefanescu, George Ana, Liviu Stefan National Research and Development Institute for Cryogenics and Isotopic Technologies—ICIT, Rm. Valcea, Romania
h i g h l i g h t s • We present the main directions of ICIT research in the field of hydrogen isotopes. • Tritium Removal Facility became a nuclear installation. • ICIT had begun the transfer of detritiation technology.
a r t i c l e
i n f o
Article history: Received 27 July 2015 Received in revised form 2 February 2016 Accepted 8 February 2016 Available online xxx Keywords: Heavy water Detritiation Tritium Cryogenics
a b s t r a c t National Research and Development Institute for Cryogenics and Isotopic Technologies (ICIT) was established in 1970 as a research focused Industrial Pilot Plant. This new Institute was created with the purpose to develop the heavy water production technology. This technology has been successfully transferred to the heavy water production plant in 1988 (with a capacity of 360 t/year). Currently, research within ICIT is focused on the following main objectives: support for the National Nuclear Program, hydrogen and fuel cells, cryogenics, environment. Within ICIT it has been built an Experimental Pilot Plant having as the main objective the development of a technology for heavy water detritiation. The purpose of this Pilot Plant is to obtain technological data and functional characteristics of specific equipment in order to design a Detritiation Facility used for Nuclear Power Plants with CANDU reactors. This work is focused on the presentation of ICIT research activities, perspectives and its capability related to water detritiation technologies and also to on issues in the field of nuclear fusion. © 2016 Elsevier B.V. All rights reserved.
1. Introduction ICIT activity has its origins in the isotope research related to the development of heavy water production technologies in Romania in the 70 s. After this task was accomplished (heavy water plant was built and operating since 1988), research and development was oriented to a new field of isotope technology and applications. The main direction of the current experimental research it focuses on studying the hydrogen isotopes and cryogenic fluids, within an experimental pilot plant for deuterium and tritium separation. These studies are possible because Institute’s staff has a tradition of fundamental aspects research of isotopes physics and chemistry, including all phases from analysis and separation methods. According to the strategy and energy policy of our country, nuclear power has an important role in satisfying the electricity demand. Because the technology used within the nuclear power
∗ Corresponding author. Fax: +40 250732746. E-mail address: marius.zamfi[email protected] (M. Zamfirache).
plant is based on CANDU type reactors, the tritium issue became very important. Details regarding ICIT activities in the field of tritium management are described further. 2. ICIT current strategy This chapter shows the main directions of Institute’s research and development in the field of hydrogen isotopes, in particularly for tritium. 2.1. Tritium Removal Facility The main department within the Institute is represented by the Tritium Removal Facility (TRF). The TRF is actually an Experimental Pilot Plant for deuterium and tritium separation. From design to present configuration, several stages have been taken. This installation project was started in 1992 as a semi-industrial plant, aiming hydrogen isotopes separation and using “Liquid Phase Catalytic Exchange–Cryogenic Distillation” process (LPCE–CD).
http://dx.doi.org/10.1016/j.fusengdes.2016.02.027 0920-3796/© 2016 Elsevier B.V. All rights reserved.
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Fig. 1. TRF block diagram.
Table 1 TRF main data.
2.2. Fusion related activities
Water flow rate
5 kg/h
Detritiation factor LPCE CD Tritium storage Tritium inventory (total) Hydrogen inventory Heavy water inventory Vapor recovery HVAC
3 1 LPCE column: Ø100 mm Helium refrigerator 1000 W, 4CD columns cascade 1 titanium ITC 1 uranium ITC 7g 15 m3 200 kg (max. 30 Ci/kg) min. 100 m3 /h 10 exchanges/h
The building was finalized in 1997 as a chemical plant, with the express purpose to provide technical support for achieving heavy water detritiation technology. There followed three years of tests and experiments until 2000 (on this configuration were completed experiments on heavy water between a wide range of concentrations and also with low tritiated water), when it started the transformation of the chemical plant into a nuclear plant. Since 2002, the plant became an Authorized Nuclear facility, in accordance with national legislation. In 2009 was brought to the plant a barrel with 200 kg of tritiated heavy water. The main changes made to the installation consisted both in terms of nuclear safety (i.e. design of safety and safety related systems, developing of commissioning and operation procedures for a nuclear facility) and technical project (i.e. upgrading of refrigeration power, improvement of LPCE catalytic package). Nowadays, we are at the pre-operational phase and foreseen that at the end of 2016 the TRF will be under normal operating conditions. The purpose of TRF is mainly to confirm the technological data and the functional characteristics of the equipments, with the final objective of designing the detritiation of heavy water facility used in CANDU reactors. Also, the facility can be used for specific studies and experiments for detritiation systems used for fusion reactors like JET and ITER. The main characteristics of the TRF are presented in Table 1.
Our Institute participated at the research and development program within ITER related to several topics, as following: 2.2.1. Tritium Plant Consortium of Associates (TriPla–CA) • A consortium of 4 EU laboratories (KIT- the leading organization, ICIT, ENEA, CEA) to support tritium activities for ITER; • TriPla-CA will benefit from the results of experiments conducted on TRF. 2.2.2. Water Detritiation System (WDS) • Developing of Process Flow Diagram and Process and Instrumentation Diagram; • Providing support for the developing of HAZOP study, followed by implementation into design of its recommendations; • Participate in the review of the WDS design; • Detailed design of WDS tritiated water holding tanks including ANSYS Static & Dynamic Analysis in ASME III, Appendix N-Dynamic Analysis. 2.2.3. Highly Tritiated Water (HTW) • Developing of Process Flow Diagram based on PERMCAT and Vapor Phase Catalytic Exchange (VPCE) technologies; • Process modeling for VPCE module within HTW system, followed by simulation in order to obtained data for design; • Participate at developing of HAZOP study for the HTW; • Feasibility study of proposed technology diagram. 2.3. Tritium analysis and environment There are two ways that Cryogenic Pilot can interact with the environment: by atmospheric release and by sewage. The tritium quantity estimated to be released by gaseous effluents is around 7.4 × 1012 Bq/year. Until now, the testing of the processes was made with heavy water, and tritiated water below the 103 Bq/kg tritium concentrations, which fulfills the exempting level from the Romanian National Regulations for nuclear facilities.
Please cite this article in press as: M. Zamfirache, et al., ICIT activities related to tritium management, Fusion Eng. Des. (2016), http://dx.doi.org/10.1016/j.fusengdes.2016.02.027
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Fig. 2. Cryogenic distillation Cold-box.
Tritium Laboratory has two main tasks: to determine tritium level during the operation of TRF, in processed tritiated heavy water, and to evaluate tritium level in the surrounding environment of the nuclear facility. This laboratory has two operational units due to the wide range of tritium radioactivity; one dedicated to the high tritium radioactivity for different samples of TRF process fluid, tritiated water leakage, tritiated effluents, and the other is dedicated to low level tritium radioactivity for the environmental samples around TRF, and for biological samples (urine), which is needed for assessing the personnel internal dose. The method used in this laboratory is liquid scintillation method, each unit having an appropriate type of liquid scintillation spectrometer: TRICARB 2800 TR (PerkinElmer) for high tritium radioactivity, and two Quantulus 1220 (PerkinElmer) for environmental tritium radioactivity [1]. Particular attention is paid to the sample preparation for LSC measurement [2]. If the process fluid of TRF is usually water, the environmental samples have a large variety: air, water, soil, homegrown products. Knowing the tritium hygroscopic property, tritiated water (HTO) is easily incorporated into biological organisms as tissue free water tritium (TFWT). Once into the tissue, tritium may label organic matter as organically bound tritium (OBT) through biological processes. Tritium level has been determined in the water extracted from environmental samples collected around
TRF [3]. OBT measurement is another type of measurement optimized for the laboratory existing equipment [4]. The Institute laboratories are designated as laboratories advised by National Committee for the Control of Nuclear Activity (CNCAN) with the Advise No. ICSI LI-01/2013, which is valid until 17 January 2016 for the measurements of high and environmental tritium activity, gamma analyses and global alpha-beta low activity sampling. The practice and specific measurement procedures developed within the laboratory were confirmed by the results obtained in the “Proficiency Test Inter-comparison Exercises” organized by the International Atomic Energy Agency Vienna, first participation being in 2000 (Sixth IAEA Inter-comparison of LowLevel Tritium Measurements in Water—TRIC2000) [5]. Other type of inter-comparison in which Tritium Laboratory was involved were: National Physical Laboratory–Teddington (Environmental Proficiecy Test Exercise 2008) and the bilateral competence testing with the Slovenian Laboratory for Liquid Scintillation Spectrometry at the Department of Low and Medium Energy Physics, from Josef Stefan Institute [6]. Tritium working group of Comissariat a l’Energie Atomique et aux Energie Alternative (CEA–EA) and Atomic Energy Canada Limited (AECL) organized an international task group on environmental OBT analysis. Tritium Laboratory participated to their intercomparison exercises and workshops, the obtained results for
Please cite this article in press as: M. Zamfirache, et al., ICIT activities related to tritium management, Fusion Eng. Des. (2016), http://dx.doi.org/10.1016/j.fusengdes.2016.02.027
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different types of sample (potatoes, sediments and wheat) not only confirming the measurement procedure, but also requiring new improvements of sample preparation procedures [7]. Tritium Laboratory was involved in different research projects, tritium level in the environment being one of the main objective projects [8,9]. The expertise of measuring low levels of tritium in the environment using LSC direct measurement without electrolytic enrichment allows to Tritium Laboratory to process large numbers of samples, essential in any monitoring program, especially of nuclear fusion facility. 3. Tritium separation technology 3.1. TRF, present status The present status of TRF it can be summarized as following characteristics (the block diagram of TRF is shown in Fig. 1): • • • • • •
Licensed for construction for 30 g tritium; Licensed for commissioning for low tritium level—initial start; Tritium on site—200 kg DTO from NPP Cernavoda; Work procedures and equipment upgrading for facility; Tritium laboratory notification; Environmental laboratory notification.
The improvements were made to the installation capacity and to the process itself in order to achieve the following objectives: • Increment of the tritium gas concentration which will be stored as metal hydride—this target will be attained mainly by increasing the refrigeration capacity to 1000 W. This upgrading also allow us to expand the range of process parameters and thus to diversify the experiments which could be done in the TRF (new cold-box shown in Fig. 2); • Introducing of improved catalytic packing into the LPCE column (the LPCE module within TRF presented in Fig. 3); • Improvement of the gas purification module; • Improvement of the isotope measurement system, both in liquid and gaseous phases (needed to certify the purity of the tritium stored and of the separation performances). 3.2. Technology transfer All the experience gained over the years within the ICIT–TRF [10] (which continues at the present days), allows us to realize the detritiation technology transfer towards NPP Cernavoda. The final objective of this transfer is the construction of Cernavoda Tritium Removal Facility (CTRF). The first stage of this technological transfer consisted in issuing and approval of the following two documents: pre-feasibility and feasibility study. The pre-feasibility study allowed us to choose the technology which will be used to the future CTRF. Starting from some basic data (i.e. detritiation factor, quantity of heavy water to be detritiated, the targeted tritium concentration) have been developed pre-conceptual design for several technological options [11]. For each option taken account, have been applied several criteria, each criterion having a weight depending on its relevance (some of the general criteria used to delimit the chosen option: minimum risk associated to personel and enviroment, operating safety, licensing, complexity, utilities cost, operating cost, overall cost). In our case, the chosen option was “Liquid Phase Catalytic Exchange–Cryogenic Distillation” (LPCE–CD). Within the feasibility study, among other information provided, we have developed conceptual design for main systems and also the
Fig. 3. LPCE module.
implementation schedule of the investment (including approvals, permits and authorizations needed). The next stage of the technological transfer was the developing of technical documentation for all systems that are part of the facility (CTRF), including safety systems, utilities, Instrumentation and Control, building. Initially as base for conceptual design, it was necessary to elaborate some documents which were used as design basis (these documents were made by our Institute staff and/or our collaborators like Kinectrics and Candesco from Canada, CITON from Romania). The documents which have been issued prior to the design phase were as following: • Authorization Framework (identify documents that will be issued to regulatory body for approval or informal, at different phases of the facility); • Safety Design Guide (provides of safety design requirements for the project, safety functions and identification of safety related systems); • Licensing Basis Document (define licensing requirements for the design, construction, operation and decommissioning of the facility); • System Classification List for Pressure Retaining Systems (list the equipments and systems in the facility and identifies the classification requirements of each according to the country’s pressure standard). There was also issued an initially safety analysis which provides a preliminary assessment of the location of the facility and the impact accidents will have on the NPP systems. Following the conceptual design was complete and includes: • Major process systems are full design;
Please cite this article in press as: M. Zamfirache, et al., ICIT activities related to tritium management, Fusion Eng. Des. (2016), http://dx.doi.org/10.1016/j.fusengdes.2016.02.027
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• Requirements for utilities and auxiliary systems; • Defining the interface with the station; • Control and safety systems philosophy and requirements. In addition, for authorization purpose were produces safety analysis for conceptual design and hydrogen behavior for CTRF. Major issues into design were considered:
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5. Conclusions One of the conclusions of this paper is to acknowledge the level of activities developed within the ICIT facility and to propose to be used as base for future projects, being the only plant of its kind at this moment that can be used either for research related to fusion (ITER) or for Tritium Removal Facilities. Results from ICIT TRF are summarized as follows:
• Location of the plant is near safety systems of the NPP, so CTRF has to be design to not affect safety operation of NPP; • Design basis earthquake was reconsider after Fukushima accident; • Tritiated water transfer by aerial double wall pipes issues; • Industrial accident (hydrogen explosion) to be consider as major event which affects the site and population (by doses to environmental).
• Process design and the facility itself based on last knowledge which permit the approach for engineering and experimental support for ITER; • Catalysts and packing for LPCE processes are fully developed and available; • Expertise for design and management for large scale TRF, referenced by CTRF project; • Operating information available, including tritium analysis and management.
As result new solutions were required into design. For hydrogen explosion event it was considered a Safe Shutdown State to limit the hydrogen inventory which contribute to an explosion who affects safety operation of NPP. During this stage there were multiple iterations, both with the beneficiary and the nuclear regulatory body. In summary, the status of the project is:
In terms of future development, ICIT consider tritium application for TRF as an actual R&D objective and therefore an important number of specialists within ICIT TRF are oriented to the major projects CTRF and ITER, assuming that in next ten years both will be constructed and expertise is required.
• Conceptual design approved; • Safety documentation for conceptual design with CNCAN (Romanian regulatory body) for approval.
Experience gained was made possible thanks to funding by the government research agency ANCSI and support provided by CNCAN (nuclear regulatory body), ISCIR (authority in the field of installation/equipment), CITON (design). Also, need to specify the productive collaboration with AECL (actual CANDU Energy), Kinectrics and Candesco (from Canada) and IS TECH (Romania). Not least, it should be mentioned the essential contribution of Tritium Removal Facility team.
The next phase of the CTRF project will be construction phase which will be developed as an turn-key project by an EPC type contract open for international biding. The current schedule shows that construction and commissioning of CTRF has to be ended up to 2022.
Acknowledgments
References 4. Management For ICIT the CTRF project (which includes TRF as support—technological transfer) is the major activity considered. From management point of view it is a medium project but as not to many nuclear project are developed in the world, specific requirements are needed. During the past phases from management point of view some issues were identified to be solved: • Lack of specialists for specific industrial level TRF (Pilot plant, CTRF); • Interfaces with authorities for both facilities, CTRF and pilot plant, as it is low experience related to authorizing framework for such plants in Romania; • Small number of suppliers of services for nuclear facilities in Romania, most of them located on Cernavoda site and not available for other projects most of the time; • Cost associated to nuclear facilities services. ICIT maintain the projects under control by developing own skills or using available specialists. However cost associated to nuclear activities produced delays for ICIT pilot plant as the institute is a state own company and authorization process by CNCAN is time consume affecting the scheduled activities.
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Please cite this article in press as: M. Zamfirache, et al., ICIT activities related to tritium management, Fusion Eng. Des. (2016), http://dx.doi.org/10.1016/j.fusengdes.2016.02.027