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Expert judgment for nuclear energy
Annals of Nuclear Energy 27 (2000) 575±588 www.elsevier.com/locate/anucene
Expert judgment for nuclear energy Young Sung Choi a, Sun Ho Lee b, Byong Whi Lee c,* a Korea Atomic Energy Research Institute, PO Box 105, Yusong-gu, Taejon 305-600, South Korea Department of Mathematics, Sejong University, Kunja-dong 98, Kwangjin-ku, Seoul, 133-747, South Korea c Department of Nuclear Engineering, Korea Advanced Institute of Science and Technology, 373-1 Kusong-dong, Yusong-ku, Taejon, 305-701, South Korea
b
Received 28 May 1999; accepted 29 June 1999
Abstract Public perception on nuclear energy is much in¯uenced by subjective impressions mostly formed through sensational and dramatic news of mass media or anti-nuclear groups. However, nuclear experts, those who have more relevant knowledge and information about nuclear energy, may have reasonable opinion based on scienti®c facts or inferences. Thus their opinion and consensus should be examined and taken into account during the process of nuclear energy policy formulation. For the purpose of eliciting experts' opinion, the webbased on-line survey system (eBOSS) was developed. Using the survey system, experts' views on nuclear energy were tallied, analyzed and compared with the public's. Based on the survey results, the paper suggests some recommendations about the future direction of the public information program in Korea. # 2000 Elsevier Science Ltd. All rights reserved.
1. Expert opinion on nuclear energy In developed countries, many technologies have experienced periods of public concern, controversy, and social opposition. Also in Korea, it turned out that nuclear issues were not only involved with scienti®c and technological concerns, but also with socio-political arguments. The successful development of nuclear technology comes to depend on the consensus of society. The public, however, does not have much knowledge of or interest in nuclear energy. Most people have concerns on potential risks from nuclear power plants and overestimate health eects by
* Corresponding author. Tel.: +82-42-869-3814; fax: +82-42-869-3810. E-mail address: [email protected] (B.W. Lee). 0306-4549/00/$ - see front matter # 2000 Elsevier Science Ltd. All rights reserved. PII: S0306-4549(99)00078-X
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radiation. Moreover, they have little interest in energy problem in their everyday lives if it does not become an issue (OKAEA, 1993). In fact, nuclear technology is complex and not completely understood. Good information may also be beyond the abilities of many lay persons to comprehend. Ordinary individuals cannot aord to do the research needed to learn enough about the mechanism of nuclear risks and ®gure out what should be done to improve safety. This is not desirable, either. So it is natural that nuclear experts have played a critical role in making nuclear energy policy. Recently, however, the role of experts in decision-making was limited in Korea. Decisions about the nuclear program entailed con¯icts between government and local communities. Although experts could identify the total bene®ts and costs of various policy alternatives, they could not objectively resolve con¯icts of interests. In addition, when confronted with value judgment, people distrusted experts and government (Kim and Hong, 1992). An acceptable policy for nuclear power may be produced through communication between the public and the experts. Nuclear experts and a decision-maker should try to catch public's perception, view, and preference on the policy alternatives which experts develop and consider best in the current situation. Then, experts and a decision-maker should modify remedial actions again or choose a policy best re¯ecting the public's preference (Spangler, 1985). In a sense, nuclear experts stand at the front- and back-end of the use and development of nuclear energy. In the paper, experts' opinions and their consensus are examined and compared with the public's. Moreover some recommendations to reduce the perception gap between the public and experts are presented. 2. Development of web-based on-line survey system for expert opinion elicitation In the few years since its inception, the World-Wide Web, or WWW or Web, has grown dramatically in the number of users. These technologies for the ®rst time hold the potential of ushering in the `Age of Information' to people of all ages, backgrounds, and economic status. Widespread networking coupled with the ease of publishing multimedia materials within the Web will support radical changes in areas such as education, business, and entertainment (Kehoe and Pitkow, 1996). It is natural and meaningful to use these networking resources for the purpose of communicating with nuclear experts. First, most nuclear experts work in research institutes, engineering service companies, regulatory agencies and government that are equipped with Internet connection. Moreover each of them has a personal computer on his/her desk which implies that he/she can access to the Internet freely. Second, there are many unresolved problems in the nuclear ®eld, not because of the non-existence of a solution, but because of lack of experts' consensus. The speedy communication makes it easy to keep one in contact with others and to reduce each other's misunderstanding. Third, there seems to be no places like an information disclosure point or public discussion forum about nuclear issues at present. Considering the fact of the explosive growth of Internet users and the national project of network construction, most people will be capable of accessing the Internet soon.
Y.S. Choi et al. / Annals of Nuclear Energy 27 (2000) 575±588
577
Thus, early eorts to build communication channels with the public may bene®t from the eect of prior occupation against anti-nuclear groups. For the current purpose of expert opinion elicitation, the web-based on-line survey system (eBOSS) was developed (Choi, 1999). Rather than using Newsgroups or electronic mail, the Web provides an easy way of answering: point-and-click forms or graphical user interface. This interface enables users to complete the survey at their own convenience and answer questions in a low-overhead fashion. It is consisted of several programs such as HTML (Hyper-Text Mark-up Language) editor, HTTP (Hyper-Text Transfer Protocol) server, and Data-Base. If questions are prepared to be asked of experts, they are edited by HTML editor to produce hyper-text pages of questionnaires. Hyper-text can include links to detailed information places and many user-friendly input forms such as choice list, text area, combo box, check box, radio checker, and button. Moreover the recent introduction of Java technology to the web has opened a variety of possibilities for interacting with users, thus improving the survey technique. Clients access the eBOSS using one of the web-browsers freely distributed. Answers are stored in Database and extracted with other data when results are requested. Database makes it possible for the eBOSS to serve many clients at the same time by the concurrent reading and writing jobs. Fig. 1 shows the conceptual diagram of the eBOSS and Fig. 2 shows the Home-page of the eBOSS. 3. Design of expert opinion survey Using the eBOSS, an expert survey on nuclear energy was conducted from August through September 1998. In order to bring respondents to the survey, several methods were used: email was delivered to the identi®ed persons and survey noti®cation was posted on the electronic bulletin board of each nuclear institute. When respondents accessed the eBOSS located at http://sorak.kaist.ac.kr/bwlee/survey/, they could participate in the survey by clicking the link as shown in Fig. 3. The questionnaire consisted of three parts: view on national bene®t of nuclear energy, risk assessment of energy systems by comparing nuclear and coal-®red power, and policy preference for improving safety satisfaction of the public. Experts know that there is not an energy system of zero risk and no cost and that a decision should be based on relative judgment by comparing feasible alternatives. Thus, all the questions were based on comparisons with coal-®red power, an alternative for base-load power generation in Korea. National bene®t is a key factor to determine which power generation system should be adopted to meet the increasing energy demand. Factors considered were economy, energy security, the ability to cope with the regulation of green house gas, and the eect of technological spin-os. Because experts have knowledge about nuclear energy, they see it without the process of perceiving risks that appears in the public judgment. They judge it directly through integrating all the factors related to the energy system. Factors submitted in this survey were two parts: ``objective and formal'' risk from the result of PSA (Probabilistic Safety Analysis) and ``subjective and informal'' risk characteristics such
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Fig. 1. Web-Based On-line Survey System (eBOSS) for expert opinion elicitation.
as large scale risk by accidents, long range risk on future generation, uncertainty of knowledge or information about the technology, and potential of abuse in war or by terror. Notations for these risk factors will be PSA, ACCIDENT, FUTURE, UNCERTAINTY, and ABUSE, respectively. In general, lay people's perceptions on risks heavily depend on characteristics of speci®c risks (Slovic, 1987). The antinuclear group often argues that the bene®t of nuclear energy is being exaggerated without considering these risk characteristics. It was our main interest whether nuclear experts take these factors into account during the risk judgment. It was investigated which policy alternative was preferred by nuclear experts for the safety of nuclear power and thus for safety satisfaction of the public. Alternatives considered were development of a new safer reactor; complete cut-o of radioactive release; resolution of disposal of trans-uranium such as Pu, Am, Np; and establishment of trust through information opening and civilian monitoring system. Fig. 4 shows the structure of questions.
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Fig. 2. Home-page of eBOSS (the ®rst page that respondents meet when accessing the Internet address http://sorak.kaist.ac.kr/bwlee/survey/).
When it is needed to ask respondents to weigh several factors, scrollbars Ð a graphic user interface of Java Ð were used as shown in Fig. 5. Scrollbar makes it possible for respondents to weigh several factors visually. The visual scale helps respondents express his thought in mind quantitatively. 4. Results of expert opinion survey 4.1. Distribution of respondents In total, 60 experts responded to all questions. Fig. 6 shows the distribution of respondents' occupational years in nuclear related ®elds. Most respondents (75%) have nuclear experience for more than 5 years. Thus it seems that respondents are nuclear experts. 4.2. National bene®ts of nuclear power Fig. 7 shows experts' view on relative weights of national bene®ts from nuclear power. Here the value has absolute meaning because respondents express their
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Fig. 3. Second window which starts the expert opinion survey activated when respondents click the survey text underlined.
thoughts according to the guide that the sum of all weight values should be 100. They could point the scale of their minds visually. The bene®t factor having the highest score was the ability to cope with the regulation of green house gas (31.1). Energy security (25.2), technological spin-os (22.5), and economy (21.3) followed it. 4.3. Overall safety judgment of experts Fig. 8 shows the distribution of experts' direct judgment on the overall safety of nuclear power compared with that of coal-®red. Here overall safety represents the integrated judgment on energy systems including the results of PSA and risk characteriscs. Over half of the respondents (56.7%) answered that nuclear power is safer than coal-®red, 28.3% that both are similar, and 15.1% that coal-®red power is safer than nuclear. 4.4. Risk assessment of experts Fig. 9 shows experts' views on relative weights of risk factors contributing to overall risk assessment of the power generation system. Seeing the ®gure, experts consider impacts on future generation most important (26.3) and the ``formal'' risk measured by PSA relatively less (17.8). Risk characteristics such as future impacts cannot be captured in PSA. From this ®gure, it seems that risk characteristics also are taken into account when judging the overall risk.
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Fig. 4. Expert judgment on nuclear energy and preference for policy alternatives.
A simple weighted sum model was proposed as experts' risk assessment structure as follows: i0 s risk judgment
X jrisk factors
Weight of ji Score on ji
1
where j is the index to PSA, ACCIDENT, FUTURE, UNCERTAINTY, and P ABUSE; (Weight of j) is the relative weight of risk factor j with jrisk factors Weight of j 100 for all i; (Score on j) is the judgmental score of safety on the risk factor j, which is scaled by 7 points Likert-scale (Table 1B). The correlation coecient between (i's risk judgment) and scores assigned to overall safety judgment (Table 1A) was 0.77 (p-value<0.001). Multiple regression model formalized by the following, i0 s overall safety judgment 0
X jrisk factors
j score on ji
2
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Fig. 5. Graphic user interface using Java. It makes it possible for respondents to weigh four items visually. The visual scale helps respondents express his thought in mind quantitatively.
Fig. 6. Distribution of respondent's occupation years in nuclear ®elds.
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Fig. 7. Expert's view on relative weights of national bene®ts from nuclear power No CO2=the ability to cope with the regulation of green house gas; Spin-os=technological spin-os; ^=mean value, =upper bound of standard error, ?=lower bound of standard error).
?
Fig. 8. Distribution of expert's direct assessment on the overall safety of nuclear power compared with coal-®red safety.
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Fig. 9. Expert's view on relative weights of risk factors contributing to overall risk assessment of power generation system (PSA=result of probabilistic safety analysis; ACCIDENT=potential of severe accident; FUTURE=impacts on future generations; UNCERTAINTY=uncertainty of knowledge; ABUSE=potential of abuse in war or by terror). Table 1 Scores assigned to answering items for overall safety judgment (A) and individual safety judgment on risk factor j (B) Question: A. From the viewpoint of overall safety judgment, I think. . . B. From the viewpoint of risk factor j, I think. . . (j=PSA, ACCIDENT, FUTURE, UNCERTAINTY, and ABUSE) Score
Answering item
1 2 3 4 5 6 7
Nuclear power is much safer than coal ®red. Nuclear power is safer than coal ®red. Nuclear power is a little safer than coal ®red. Neutral Coal ®red power is a little safer than nuclear. Coal ®red power is safer than nuclear. Coal ®red power is much safer than nuclear.
shows a bit higher value of correlation, 0.79. But the parameter estimates as shown in Table 2 are not consistent with the averages of self-stated weightings. The most in¯uential factor is PSA and the next is UNCERTAINY and FUTURE. This mismatch between self-stated weighting and derived one seems to indicate that although experts think explicitly that risk characteristics are important, their judgments should be implicitly governed by the objective risk. However, since the dierence
Y.S. Choi et al. / Annals of Nuclear Energy 27 (2000) 575±588
585
Table 2 Parameter estimates and standard errors of the multiple regression model
Intercept PSA ACCIDENT FUTURE UNCERTAINTY ABUSE
Estimates
Standard error
p-value
ÿ0.72 0.35 0.01 0.26 0.30 0.17
0.54 0.10 0.08 0.12 0.11 0.08
0.19 0.00 0.91 0.03 0.01 0.03
between models (1) and (2) is very small, we could not determine the best model. Moreover since both model show somewhat low correlation with actual judgment, we concluded that neither model suciently represents the experts' risk judgment structure. However, at least, considering that the correlation coecient with PSA factor is lower than model (1) or (2) as shown in Table 3, we could verify that in risk judgment process experts take into account not only objective risk but also risk characteristics. 4.5. Preferences on policy alternatives Fig. 10 shows experts' preferences on policies to improve the safety of nuclear power and thus to improve safety satisfaction of the public. It shows that most experts require establishment of trust through information opening and civilian monitoring system. This is consistent with the statement of the President of Korea, that the civilian monitoring system would be established soon, in the ceremony for the completion of new nuclear power plant, Ulchin 3 unit, in Korea. Table 3 Comparisons of correlation coecients between actual overall safety judgment and some proposed model for risk assessment Model
Correlation coecient
Weighed sum P jriskfactors (weight of j)i(Score on j)i
0.77
Multiple regression P 0 jriskfactors j (Score on j)i
0.79
Simple additive P jriskfactors (Score on j)i
0.75
One factor (Score on PSA) (Score on ACCIDENT) (Score on FUTURE) (Score on UNCERTAINTY) (Score on ABUSE)
0.60 0.35 0.64 0.57 0.36
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Fig. 10. Expert's preferences on policies to improve safety satisfaction of the public (New Rx=development of new safer reactor; No Rad=complete cut-o of radioactive release; Trans-U=solving the problems of treatment and/or disposal of trans-uranium such as Pu, Am, Np; Trust=establishment of trust through information opening and civilian monitoring system).
5. Discussions The scope of nuclear expert was not de®ned rigorously in this study. If the respondent came from a nuclear-related organization, he was considered as a nuclear expert. We examined if any dierence in opinion exists along with dierent occupation years or organizations. But no signi®cant dierences were observed. It seems that experts have somewhat similar opinion in most issues of nuclear energy. Almost all respondents consider nuclear power as more bene®cial than coal-®red power. And most think nuclear power to be as safe as or safer than coal-®red power. In addition, standard errors of weights on bene®t, risk, and policy preference were small enough for some key weights to be discriminated. When compared with the public, there are dierences of perception by experts on the risk and bene®t of nuclear energy. While the public considers nuclear energy as risk- and economy-oriented energy, experts consider nuclear energy as safe and important as a viable option for preparing for global warming gas emission control (Table 4). Global warming is one of the most important environmental issues and the fossil fuel consumption is the main cause of it. On this account, the nuclear power is highly estimated as a non-fossil energy source. However, a recent national survey revealed that 37.5% of the public think gas energy to be eective in reducing global warming gas, 16.5% coal, and 8.1% oil, while 31.4% think nuclear energy to be eective (no response 6.5%) (OKAEA, 1998). In other words, about 70% of Korean publics do not recognize this advantage of nuclear energy.
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587
Table 4 Comparisons of the public and experts The public
Experts (in this study)
Perception on bene®t NPP is ecenomica Agree 83.3% vs. disagree 12% NPP produces no CO2a Agree 55.6% vs. disagree 35.1%
Bene®t of NPP Economy 21.3 vs. no CO2 31.1 (Security 25.2, spin-os 22.5)
Perception on safety (risk) NPP is not safe 45.4%b NPP is risky compared with other industrial facilities 54.3a
NPP is as safe as or safer than coal-®red: 85.0%
a b
KINS (1995), Sample size=1500, survey date=August 1995. Gallup Korea (1997), sample size=1524, survey date=October 1997.
This dramatically shows a dierence between lay people and experts. The misunderstanding of such an important point for decision should be corrected by proper public information. In fact, OKAEA (Organization for Korea Atomic Energy Awareness), responsible for public information, has focused TV advertisements of nuclear energy on economic resource until recently. The misunderstanding can be reduced by providing speci®c information like that only nuclear energy could cope with global CO2 emission control and future electricity demand in Korea. While lay people judge the risk and bene®t through the process of perception on the speci®c object, an expert judges them on the basis of objective information. That is, those who have little interests or concerns base their judgement on the perceptions formed mostly by sensational or attractive information (Choi et al., 1998). But it is assumed that experts take all relevant scienti®c facts or inferences into account as much as possible. Letting them weigh risk factors, it is found that experts consider impacts on future generations most important and the ``formal'' risk measured by PSA relatively less. Although we could not ®nd out expert risk judgment model, it might be true that risk characteristics not captured in PSA should be taken into account when experts judge the risk of nuclear energy. The on-line survey system produced a very good performance. It required very low cost and manpower. Speedy response is another merit of the on-line system. Most respondents showed favorable responses, which can be seen in free comments. Any type of survey can be done with the ability of Java. It seems that this could play the role of communicating experts' opinion to the public. The goal of such communication should be not simply to `educate' the public to accept the technology, but to provide individuals with the scienti®c information enabling them to make an informed choice about energy systems and to make a contribution to the wider public debate.
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6. Conclusions The ®rst priority for promoting the nuclear power program must be the economically favorable production of electricity compared with other available alternatives such as coal-®red power. When global warming gas is controlled within an international regime, nuclear energy will be more favorable. According to this fact, nuclear experts in Korea think that nuclear energy must be the viable option for preparing for global warming gas emission control. But about 70% of Korean publics do not recognize this advantage of nuclear energy. In addition, while most nuclear experts consider nuclear energy as safer than coal-®red one, about half of the public thinks that nuclear energy is not safe. Public acceptance and cooperation are prerequisites for future development and utilization of nuclear energy. For nuclear energy to be an advanced and innovative environmentally sound technology in the 21st century, the public mis-perceptions should be corrected through proper education and public information. References Choi, Y.S., 1999. A Study on the Social Risk-Judgment for Nuclear Energy. Ph.D dissertation, Korea Advanced Institute of Science and Technology. Choi, Y.S., Lee, S.H., Cho, N.Z., Lee, B.W., 1998. Development of the public attitude model toward nuclear power in Korea. Annals of Nuclear Energy, 25(12). Gallup Korea, 1997. National Survey of Public's Attitude toward Nuclear Energy, Unpublished Gallup Report, (in Korean). Kehoe, C.M., Pitkow, P., 1996. Surveying the territory: GVU's ®ve WWW user surveys. The World Wide Web Journal, 1(3). Kim, K.D., Hong, D.S., 1992. Nuclear Energy and Local Acceptance: Sociological Approach, Seoul National University Press, (in Korean). KINS (Korea Institute of Nuclear Safety), 1995. Survey Report on the People's Perception of Nuclear Safety and Regulation (KINS Report) (in Korean). OKAEA (Organization for Korea Atomic Energy Awareness), 1993. National Survey Report on Public's Attitude toward Nuclear Energy (in Korean). OKAEA (Organization for Korea Atomic Energy Awareness), 1998. National Survey Report on Climate Changes, (in Korean). Slovic, P., 1987. Perception of risk. Science, 236(17). Spangler, M.B., 1985. Heuristic opinion and preference evaluaion research for assessing technological options Ð a user's view. In Covello, V.T. et al. (Eds.), Environmental Impact Assessment, Technology Assessment, and Risk Analysis. NATO ASI Series, Vol. G4. Springer±Verlag.
Expert judgment for nuclear energy Young Sung Choi a, Sun Ho Lee b, Byong Whi Lee c,* a Korea Atomic Energy Research Institute, PO Box 105, Yusong-gu, Taejon 305-600, South Korea Department of Mathematics, Sejong University, Kunja-dong 98, Kwangjin-ku, Seoul, 133-747, South Korea c Department of Nuclear Engineering, Korea Advanced Institute of Science and Technology, 373-1 Kusong-dong, Yusong-ku, Taejon, 305-701, South Korea
b
Received 28 May 1999; accepted 29 June 1999
Abstract Public perception on nuclear energy is much in¯uenced by subjective impressions mostly formed through sensational and dramatic news of mass media or anti-nuclear groups. However, nuclear experts, those who have more relevant knowledge and information about nuclear energy, may have reasonable opinion based on scienti®c facts or inferences. Thus their opinion and consensus should be examined and taken into account during the process of nuclear energy policy formulation. For the purpose of eliciting experts' opinion, the webbased on-line survey system (eBOSS) was developed. Using the survey system, experts' views on nuclear energy were tallied, analyzed and compared with the public's. Based on the survey results, the paper suggests some recommendations about the future direction of the public information program in Korea. # 2000 Elsevier Science Ltd. All rights reserved.
1. Expert opinion on nuclear energy In developed countries, many technologies have experienced periods of public concern, controversy, and social opposition. Also in Korea, it turned out that nuclear issues were not only involved with scienti®c and technological concerns, but also with socio-political arguments. The successful development of nuclear technology comes to depend on the consensus of society. The public, however, does not have much knowledge of or interest in nuclear energy. Most people have concerns on potential risks from nuclear power plants and overestimate health eects by
* Corresponding author. Tel.: +82-42-869-3814; fax: +82-42-869-3810. E-mail address: [email protected] (B.W. Lee). 0306-4549/00/$ - see front matter # 2000 Elsevier Science Ltd. All rights reserved. PII: S0306-4549(99)00078-X
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Y.S. Choi et al. / Annals of Nuclear Energy 27 (2000) 575±588
radiation. Moreover, they have little interest in energy problem in their everyday lives if it does not become an issue (OKAEA, 1993). In fact, nuclear technology is complex and not completely understood. Good information may also be beyond the abilities of many lay persons to comprehend. Ordinary individuals cannot aord to do the research needed to learn enough about the mechanism of nuclear risks and ®gure out what should be done to improve safety. This is not desirable, either. So it is natural that nuclear experts have played a critical role in making nuclear energy policy. Recently, however, the role of experts in decision-making was limited in Korea. Decisions about the nuclear program entailed con¯icts between government and local communities. Although experts could identify the total bene®ts and costs of various policy alternatives, they could not objectively resolve con¯icts of interests. In addition, when confronted with value judgment, people distrusted experts and government (Kim and Hong, 1992). An acceptable policy for nuclear power may be produced through communication between the public and the experts. Nuclear experts and a decision-maker should try to catch public's perception, view, and preference on the policy alternatives which experts develop and consider best in the current situation. Then, experts and a decision-maker should modify remedial actions again or choose a policy best re¯ecting the public's preference (Spangler, 1985). In a sense, nuclear experts stand at the front- and back-end of the use and development of nuclear energy. In the paper, experts' opinions and their consensus are examined and compared with the public's. Moreover some recommendations to reduce the perception gap between the public and experts are presented. 2. Development of web-based on-line survey system for expert opinion elicitation In the few years since its inception, the World-Wide Web, or WWW or Web, has grown dramatically in the number of users. These technologies for the ®rst time hold the potential of ushering in the `Age of Information' to people of all ages, backgrounds, and economic status. Widespread networking coupled with the ease of publishing multimedia materials within the Web will support radical changes in areas such as education, business, and entertainment (Kehoe and Pitkow, 1996). It is natural and meaningful to use these networking resources for the purpose of communicating with nuclear experts. First, most nuclear experts work in research institutes, engineering service companies, regulatory agencies and government that are equipped with Internet connection. Moreover each of them has a personal computer on his/her desk which implies that he/she can access to the Internet freely. Second, there are many unresolved problems in the nuclear ®eld, not because of the non-existence of a solution, but because of lack of experts' consensus. The speedy communication makes it easy to keep one in contact with others and to reduce each other's misunderstanding. Third, there seems to be no places like an information disclosure point or public discussion forum about nuclear issues at present. Considering the fact of the explosive growth of Internet users and the national project of network construction, most people will be capable of accessing the Internet soon.
Y.S. Choi et al. / Annals of Nuclear Energy 27 (2000) 575±588
577
Thus, early eorts to build communication channels with the public may bene®t from the eect of prior occupation against anti-nuclear groups. For the current purpose of expert opinion elicitation, the web-based on-line survey system (eBOSS) was developed (Choi, 1999). Rather than using Newsgroups or electronic mail, the Web provides an easy way of answering: point-and-click forms or graphical user interface. This interface enables users to complete the survey at their own convenience and answer questions in a low-overhead fashion. It is consisted of several programs such as HTML (Hyper-Text Mark-up Language) editor, HTTP (Hyper-Text Transfer Protocol) server, and Data-Base. If questions are prepared to be asked of experts, they are edited by HTML editor to produce hyper-text pages of questionnaires. Hyper-text can include links to detailed information places and many user-friendly input forms such as choice list, text area, combo box, check box, radio checker, and button. Moreover the recent introduction of Java technology to the web has opened a variety of possibilities for interacting with users, thus improving the survey technique. Clients access the eBOSS using one of the web-browsers freely distributed. Answers are stored in Database and extracted with other data when results are requested. Database makes it possible for the eBOSS to serve many clients at the same time by the concurrent reading and writing jobs. Fig. 1 shows the conceptual diagram of the eBOSS and Fig. 2 shows the Home-page of the eBOSS. 3. Design of expert opinion survey Using the eBOSS, an expert survey on nuclear energy was conducted from August through September 1998. In order to bring respondents to the survey, several methods were used: email was delivered to the identi®ed persons and survey noti®cation was posted on the electronic bulletin board of each nuclear institute. When respondents accessed the eBOSS located at http://sorak.kaist.ac.kr/bwlee/survey/, they could participate in the survey by clicking the link as shown in Fig. 3. The questionnaire consisted of three parts: view on national bene®t of nuclear energy, risk assessment of energy systems by comparing nuclear and coal-®red power, and policy preference for improving safety satisfaction of the public. Experts know that there is not an energy system of zero risk and no cost and that a decision should be based on relative judgment by comparing feasible alternatives. Thus, all the questions were based on comparisons with coal-®red power, an alternative for base-load power generation in Korea. National bene®t is a key factor to determine which power generation system should be adopted to meet the increasing energy demand. Factors considered were economy, energy security, the ability to cope with the regulation of green house gas, and the eect of technological spin-os. Because experts have knowledge about nuclear energy, they see it without the process of perceiving risks that appears in the public judgment. They judge it directly through integrating all the factors related to the energy system. Factors submitted in this survey were two parts: ``objective and formal'' risk from the result of PSA (Probabilistic Safety Analysis) and ``subjective and informal'' risk characteristics such
578
Y.S. Choi et al. / Annals of Nuclear Energy 27 (2000) 575±588
Fig. 1. Web-Based On-line Survey System (eBOSS) for expert opinion elicitation.
as large scale risk by accidents, long range risk on future generation, uncertainty of knowledge or information about the technology, and potential of abuse in war or by terror. Notations for these risk factors will be PSA, ACCIDENT, FUTURE, UNCERTAINTY, and ABUSE, respectively. In general, lay people's perceptions on risks heavily depend on characteristics of speci®c risks (Slovic, 1987). The antinuclear group often argues that the bene®t of nuclear energy is being exaggerated without considering these risk characteristics. It was our main interest whether nuclear experts take these factors into account during the risk judgment. It was investigated which policy alternative was preferred by nuclear experts for the safety of nuclear power and thus for safety satisfaction of the public. Alternatives considered were development of a new safer reactor; complete cut-o of radioactive release; resolution of disposal of trans-uranium such as Pu, Am, Np; and establishment of trust through information opening and civilian monitoring system. Fig. 4 shows the structure of questions.
Y.S. Choi et al. / Annals of Nuclear Energy 27 (2000) 575±588
579
Fig. 2. Home-page of eBOSS (the ®rst page that respondents meet when accessing the Internet address http://sorak.kaist.ac.kr/bwlee/survey/).
When it is needed to ask respondents to weigh several factors, scrollbars Ð a graphic user interface of Java Ð were used as shown in Fig. 5. Scrollbar makes it possible for respondents to weigh several factors visually. The visual scale helps respondents express his thought in mind quantitatively. 4. Results of expert opinion survey 4.1. Distribution of respondents In total, 60 experts responded to all questions. Fig. 6 shows the distribution of respondents' occupational years in nuclear related ®elds. Most respondents (75%) have nuclear experience for more than 5 years. Thus it seems that respondents are nuclear experts. 4.2. National bene®ts of nuclear power Fig. 7 shows experts' view on relative weights of national bene®ts from nuclear power. Here the value has absolute meaning because respondents express their
580
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Fig. 3. Second window which starts the expert opinion survey activated when respondents click the survey text underlined.
thoughts according to the guide that the sum of all weight values should be 100. They could point the scale of their minds visually. The bene®t factor having the highest score was the ability to cope with the regulation of green house gas (31.1). Energy security (25.2), technological spin-os (22.5), and economy (21.3) followed it. 4.3. Overall safety judgment of experts Fig. 8 shows the distribution of experts' direct judgment on the overall safety of nuclear power compared with that of coal-®red. Here overall safety represents the integrated judgment on energy systems including the results of PSA and risk characteriscs. Over half of the respondents (56.7%) answered that nuclear power is safer than coal-®red, 28.3% that both are similar, and 15.1% that coal-®red power is safer than nuclear. 4.4. Risk assessment of experts Fig. 9 shows experts' views on relative weights of risk factors contributing to overall risk assessment of the power generation system. Seeing the ®gure, experts consider impacts on future generation most important (26.3) and the ``formal'' risk measured by PSA relatively less (17.8). Risk characteristics such as future impacts cannot be captured in PSA. From this ®gure, it seems that risk characteristics also are taken into account when judging the overall risk.
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Fig. 4. Expert judgment on nuclear energy and preference for policy alternatives.
A simple weighted sum model was proposed as experts' risk assessment structure as follows: i0 s risk judgment
X jrisk factors
Weight of ji Score on ji
1
where j is the index to PSA, ACCIDENT, FUTURE, UNCERTAINTY, and P ABUSE; (Weight of j) is the relative weight of risk factor j with jrisk factors Weight of j 100 for all i; (Score on j) is the judgmental score of safety on the risk factor j, which is scaled by 7 points Likert-scale (Table 1B). The correlation coecient between (i's risk judgment) and scores assigned to overall safety judgment (Table 1A) was 0.77 (p-value<0.001). Multiple regression model formalized by the following, i0 s overall safety judgment 0
X jrisk factors
j score on ji
2
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Fig. 5. Graphic user interface using Java. It makes it possible for respondents to weigh four items visually. The visual scale helps respondents express his thought in mind quantitatively.
Fig. 6. Distribution of respondent's occupation years in nuclear ®elds.
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Fig. 7. Expert's view on relative weights of national bene®ts from nuclear power No CO2=the ability to cope with the regulation of green house gas; Spin-os=technological spin-os; ^=mean value, =upper bound of standard error, ?=lower bound of standard error).
?
Fig. 8. Distribution of expert's direct assessment on the overall safety of nuclear power compared with coal-®red safety.
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Fig. 9. Expert's view on relative weights of risk factors contributing to overall risk assessment of power generation system (PSA=result of probabilistic safety analysis; ACCIDENT=potential of severe accident; FUTURE=impacts on future generations; UNCERTAINTY=uncertainty of knowledge; ABUSE=potential of abuse in war or by terror). Table 1 Scores assigned to answering items for overall safety judgment (A) and individual safety judgment on risk factor j (B) Question: A. From the viewpoint of overall safety judgment, I think. . . B. From the viewpoint of risk factor j, I think. . . (j=PSA, ACCIDENT, FUTURE, UNCERTAINTY, and ABUSE) Score
Answering item
1 2 3 4 5 6 7
Nuclear power is much safer than coal ®red. Nuclear power is safer than coal ®red. Nuclear power is a little safer than coal ®red. Neutral Coal ®red power is a little safer than nuclear. Coal ®red power is safer than nuclear. Coal ®red power is much safer than nuclear.
shows a bit higher value of correlation, 0.79. But the parameter estimates as shown in Table 2 are not consistent with the averages of self-stated weightings. The most in¯uential factor is PSA and the next is UNCERTAINY and FUTURE. This mismatch between self-stated weighting and derived one seems to indicate that although experts think explicitly that risk characteristics are important, their judgments should be implicitly governed by the objective risk. However, since the dierence
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Table 2 Parameter estimates and standard errors of the multiple regression model
Intercept PSA ACCIDENT FUTURE UNCERTAINTY ABUSE
Estimates
Standard error
p-value
ÿ0.72 0.35 0.01 0.26 0.30 0.17
0.54 0.10 0.08 0.12 0.11 0.08
0.19 0.00 0.91 0.03 0.01 0.03
between models (1) and (2) is very small, we could not determine the best model. Moreover since both model show somewhat low correlation with actual judgment, we concluded that neither model suciently represents the experts' risk judgment structure. However, at least, considering that the correlation coecient with PSA factor is lower than model (1) or (2) as shown in Table 3, we could verify that in risk judgment process experts take into account not only objective risk but also risk characteristics. 4.5. Preferences on policy alternatives Fig. 10 shows experts' preferences on policies to improve the safety of nuclear power and thus to improve safety satisfaction of the public. It shows that most experts require establishment of trust through information opening and civilian monitoring system. This is consistent with the statement of the President of Korea, that the civilian monitoring system would be established soon, in the ceremony for the completion of new nuclear power plant, Ulchin 3 unit, in Korea. Table 3 Comparisons of correlation coecients between actual overall safety judgment and some proposed model for risk assessment Model
Correlation coecient
Weighed sum P jriskfactors (weight of j)i(Score on j)i
0.77
Multiple regression P 0 jriskfactors j (Score on j)i
0.79
Simple additive P jriskfactors (Score on j)i
0.75
One factor (Score on PSA) (Score on ACCIDENT) (Score on FUTURE) (Score on UNCERTAINTY) (Score on ABUSE)
0.60 0.35 0.64 0.57 0.36
586
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Fig. 10. Expert's preferences on policies to improve safety satisfaction of the public (New Rx=development of new safer reactor; No Rad=complete cut-o of radioactive release; Trans-U=solving the problems of treatment and/or disposal of trans-uranium such as Pu, Am, Np; Trust=establishment of trust through information opening and civilian monitoring system).
5. Discussions The scope of nuclear expert was not de®ned rigorously in this study. If the respondent came from a nuclear-related organization, he was considered as a nuclear expert. We examined if any dierence in opinion exists along with dierent occupation years or organizations. But no signi®cant dierences were observed. It seems that experts have somewhat similar opinion in most issues of nuclear energy. Almost all respondents consider nuclear power as more bene®cial than coal-®red power. And most think nuclear power to be as safe as or safer than coal-®red power. In addition, standard errors of weights on bene®t, risk, and policy preference were small enough for some key weights to be discriminated. When compared with the public, there are dierences of perception by experts on the risk and bene®t of nuclear energy. While the public considers nuclear energy as risk- and economy-oriented energy, experts consider nuclear energy as safe and important as a viable option for preparing for global warming gas emission control (Table 4). Global warming is one of the most important environmental issues and the fossil fuel consumption is the main cause of it. On this account, the nuclear power is highly estimated as a non-fossil energy source. However, a recent national survey revealed that 37.5% of the public think gas energy to be eective in reducing global warming gas, 16.5% coal, and 8.1% oil, while 31.4% think nuclear energy to be eective (no response 6.5%) (OKAEA, 1998). In other words, about 70% of Korean publics do not recognize this advantage of nuclear energy.
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Table 4 Comparisons of the public and experts The public
Experts (in this study)
Perception on bene®t NPP is ecenomica Agree 83.3% vs. disagree 12% NPP produces no CO2a Agree 55.6% vs. disagree 35.1%
Bene®t of NPP Economy 21.3 vs. no CO2 31.1 (Security 25.2, spin-os 22.5)
Perception on safety (risk) NPP is not safe 45.4%b NPP is risky compared with other industrial facilities 54.3a
NPP is as safe as or safer than coal-®red: 85.0%
a b
KINS (1995), Sample size=1500, survey date=August 1995. Gallup Korea (1997), sample size=1524, survey date=October 1997.
This dramatically shows a dierence between lay people and experts. The misunderstanding of such an important point for decision should be corrected by proper public information. In fact, OKAEA (Organization for Korea Atomic Energy Awareness), responsible for public information, has focused TV advertisements of nuclear energy on economic resource until recently. The misunderstanding can be reduced by providing speci®c information like that only nuclear energy could cope with global CO2 emission control and future electricity demand in Korea. While lay people judge the risk and bene®t through the process of perception on the speci®c object, an expert judges them on the basis of objective information. That is, those who have little interests or concerns base their judgement on the perceptions formed mostly by sensational or attractive information (Choi et al., 1998). But it is assumed that experts take all relevant scienti®c facts or inferences into account as much as possible. Letting them weigh risk factors, it is found that experts consider impacts on future generations most important and the ``formal'' risk measured by PSA relatively less. Although we could not ®nd out expert risk judgment model, it might be true that risk characteristics not captured in PSA should be taken into account when experts judge the risk of nuclear energy. The on-line survey system produced a very good performance. It required very low cost and manpower. Speedy response is another merit of the on-line system. Most respondents showed favorable responses, which can be seen in free comments. Any type of survey can be done with the ability of Java. It seems that this could play the role of communicating experts' opinion to the public. The goal of such communication should be not simply to `educate' the public to accept the technology, but to provide individuals with the scienti®c information enabling them to make an informed choice about energy systems and to make a contribution to the wider public debate.
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6. Conclusions The ®rst priority for promoting the nuclear power program must be the economically favorable production of electricity compared with other available alternatives such as coal-®red power. When global warming gas is controlled within an international regime, nuclear energy will be more favorable. According to this fact, nuclear experts in Korea think that nuclear energy must be the viable option for preparing for global warming gas emission control. But about 70% of Korean publics do not recognize this advantage of nuclear energy. In addition, while most nuclear experts consider nuclear energy as safer than coal-®red one, about half of the public thinks that nuclear energy is not safe. Public acceptance and cooperation are prerequisites for future development and utilization of nuclear energy. For nuclear energy to be an advanced and innovative environmentally sound technology in the 21st century, the public mis-perceptions should be corrected through proper education and public information. References Choi, Y.S., 1999. A Study on the Social Risk-Judgment for Nuclear Energy. Ph.D dissertation, Korea Advanced Institute of Science and Technology. Choi, Y.S., Lee, S.H., Cho, N.Z., Lee, B.W., 1998. Development of the public attitude model toward nuclear power in Korea. Annals of Nuclear Energy, 25(12). Gallup Korea, 1997. National Survey of Public's Attitude toward Nuclear Energy, Unpublished Gallup Report, (in Korean). Kehoe, C.M., Pitkow, P., 1996. Surveying the territory: GVU's ®ve WWW user surveys. The World Wide Web Journal, 1(3). Kim, K.D., Hong, D.S., 1992. Nuclear Energy and Local Acceptance: Sociological Approach, Seoul National University Press, (in Korean). KINS (Korea Institute of Nuclear Safety), 1995. Survey Report on the People's Perception of Nuclear Safety and Regulation (KINS Report) (in Korean). OKAEA (Organization for Korea Atomic Energy Awareness), 1993. National Survey Report on Public's Attitude toward Nuclear Energy (in Korean). OKAEA (Organization for Korea Atomic Energy Awareness), 1998. National Survey Report on Climate Changes, (in Korean). Slovic, P., 1987. Perception of risk. Science, 236(17). Spangler, M.B., 1985. Heuristic opinion and preference evaluaion research for assessing technological options Ð a user's view. In Covello, V.T. et al. (Eds.), Environmental Impact Assessment, Technology Assessment, and Risk Analysis. NATO ASI Series, Vol. G4. Springer±Verlag.