ML18022B145
| ML18022B145 | |
| Person / Time | |
|---|---|
| Site: | McGuire  |
| Issue date: | 01/19/1979 |
| From: | Ingram F NRC OFFICE OF PUBLIC AFFAIRS (OPA) |
| To: | |
| Shared Package | |
| ML18022B146 | List: |
| References | |
| PR-79-019, PR-79-19, NUDOCS 7902260119 | |
| Download: ML18022B145 (11) | |
Text
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~y 0 y*y4 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF PUBLIC AFFAIRS WASHINGTON, D.C.
20555 No.
79-19
Contact:
Frank L. Ingram Tel.
301/492-7715 FOR IMMEDIATE RELEASE (Mailed' January 19, 1979)
NUCLEAR REGULATORY COIIMISSION ISSUES POLICY STATEMENT ON REACTOR SAFETY STUDY AND REVIEW BY LEWIS PANEL The Nuclear Regulatory Commission today issued a state-ment of policy concerning its views of the Reactor Safety Study (WASH-1400)* in light of criticisms of the study made by a special review group headed by Dr. Harold Lewis of the University of California at Santa Barbara.
The Commission said it accepts the findings of the review group and is taking actions to respond to them.
A copy of the Commission's policy statement is attached.
The policy statement noted that while praising the"study's general methodology and recognizing its contribution to assess-ing the risks of nuclear
- power, the Review Group was critical of the Executive
- Summary, the procedure followed in producing the final report, and the calculations in the body of the report.
The Review Group also criticized, in some cases
- severely, various calculational techniques in the study as well as its lack of clarity.
The Review Group indicated the Executive Summary is a poor description of the contents of the report and should not be portrayed as such, does not adequately indi-cate the full extent of the consequences of reactor accidents, and does not sufficiently emphasize the uncertainties involved in the calculation of their probability.
The Review Group concluded the Executive Summary has lent itself to misuse in the discussion of reactor risks.
The Review Group criticized the peer review process, pointing out that in some cases cogent comments from critics either were not acknowledged or were'vaded.
The Review Group concluded that the error* bounds on accident probabilities were greatly understated.
79-19 The Reactor Safety Study was begun under the auspices of the former Atomic Energy Commission and a draft version was circulated for comment in April, 1974.
The, final report was made public on October 30, 1975 by the Nuclear Regulatory Commission, which assumed the regulatory functions of the former AEC in January,'975.
Criticism of the study has centered on tne method of treating peer comments on the draft report as well as on the substance of the final report.
.Following letters from Congressman Norris Udall, Chair-man of the House Committee on Interior and Insular Affairs expressing misgivings about the Reactor Safety Study, and in particular about the Executive Summary published with the main report, the Commission established a Risk Assessment.
Review Group in July, 1977.
The Commission said it expected that the review group, headed by Dr. Lewis, would assist the Commission in establishing a policy regarding the use of risk assessment in the regulatory process and would clarify the achievements and limitations of the Reactor Safety Study.
The Review Group submitted its report on September 7,
1978.
In its policy statement, the Commission said:
(1)
It withdraws any explicit or implicit past endorse-ment of the Executive Summary.
{2) It agrees that the peer review process followed in publishing WASH-1400 was inadequate and that proper peer review is fundamental to making sound tech-nical decisions.
The Commission will take whatever corrective action is necessary to assure that effec-tive peer review is an integral feature of the NRC's risk assessment program.
(3) It accepts the Review Group Report '
conclusion that absolute values of the risks presented by NASH-1400 should not be used uncritically either in the regulatory process or for public policy purposes and has taken and will continue to take steps to assure that any such use in the past will be corrected as appropriate.
In particular, in light of the Review Group's conclusions on accident.
probabilities, the Commission does not-regard a~
reliable the Reactor Safety Study's numerical esti-mate of the overall risk of reactor accident.
79-19 (4) It has directed that a review be made of Commission correspondence and statements involving NASH-1400 and corrective action as necessary will be taken.
The Commission also said that with respect to the com-ponent parts of the Reactor Sa ety Study, it expects its staff to make use of them as appropriate, that is, where the data base is adequate and analytical techniques permit.
The Commission also said that, taking due account of the reserva-tions expressed by the Review Group, it supports the extended use of probabilistic risk assessment in regulatory decision-making.
It said that the NRC staff has been provided with additional detailed instructions concerning continued use of risk assessment techniques and results.
- WASH-1400 also is known as the "Rasmussen Report.."
Attachment
January 18, 1979 NRC STATEtiENT Of) RISK ASSESSMENT AND THE REACTOR SAFETY STUDY REPORT (WASH-1400)
IN LIGHT OF THE RISK ASSESSMENT RE'IIEW GROUP REPORT The Risk Assessment Review Group, chartered by the NRC in July, 1977 to "provide advice and information to the Commission on the final report of the Reactor Safety Study, WASH-1400," and related matters, 1/
submitted its report to the Commission on September 7,
1978.
The Review Group, chaired by Professor Harold Lewis of the University of California at Santa
- Barbara, 2/ was formed in response to letters from Congressman Udall, Chairman of the House Committee on Interior and insular Affairs, expressing misgivings about the Peactor Safety Study (WASH-1400),
and in particular about the "Executive Summary" published with the.!tain Report.
It was expected that the Review Group's report would "assist the CoNiillsslon in establishing policy regarding the use of risk assessment in the regulatory process" and that it would "clarify the achievements and limitations of the Reactor Safety Study."
In August, 1972, the Chairman of the Atomic Energy Commission informed the Chairman of the Joint Committee on Atomic Energy that the Atomic Energy Commission had undertaken an in-house study "to provide a
basis for submitting reconimendations to the Congress regarding the extension or modification of the Price-Anderson Act."
A draft version of the study report was circulated for conment in April, 1974.
On October 30, 1975, the Nuclear Regulatory Commission 3/ announced that the final report had been completed.
Criticism of the document following release centered on the method of treating peer comments on the draft report as well as on the substance of the repor't.
The NRC press release accompanying publication of WASH-1400 praised the report, describing it as a "realistic assessment...,
providing an objective and meaningful estimate of the present risks associated with the operation of present day light water reactors in the United States,"
gave several comparisons to show that the risk from nuclear power was much less than from other man-made activities, and included a statement that "the final report is a soundly based arid impressive'ork....
Its overall conclusion is that the risk attached to the operation of nuclear power plants is very low compared with other natural and man-made risks." 4/
ln view of the importance attached to the Reactor Safety Study, within and outside the Commission, both prospectively and after it was made public, the Commission has reexamined it's views reaarding the Study'n light of the Review Group's critique.
While praising the study's general methodology and tecognizing its contribution to assessing the risks of nuclear power, the Review Group was critical of the Executive
- Summary, the procedure followed in producing the final report and the calculations in the body of the report.
Among the major failings of the study, the Review Group cited:
The Executive Summary:
The Review Group concluded that "the Executive Summary of the RSS is a poor description of the contents of the report, should not be portrayed as such, and has lent itself to misuse in the discussion of reactor risks."
The Review Group indicated the Executive Summary does not adequately indicate the full extent of the consequences of reactor accidents and does not sufficiently emphasize the uncertainties involved in the calculations of their probability.
As a result, the reader may be left with a misplaced confidence in the validity of the risk estimates and a more favorable impression of reactor risks in comparison with other risks than warranted by the study.
5/
The Peer Review Process:
The Review Group Report criticized the RSS staff response, pointing out that in some cases cogent comments from critics either were not acknowledged or were evaded and that, in general, the record of response to valid criticism was weaker than it should have been.
The Report points out that the lack of clarity of WASH-1400 itself led to major diffi-culty in tracing a line of thought through the study and crippled many efforts to accomplish responsible peer reviews.
Accident Probabilities:
The Review Group was unable to deter-mine whether the absolute probabilities of accident sequences in WASH-1400 are high or low, but believes that the error bounds on those estimates are, in general, greatly understated.
This, the Report said, is true in part because there is in many cases an inadequate data
- base, in part because of an inability to quantify common cause failures, and in part because of some questionable methodological and statistical procedures.
The Review Group also criticized, in some cases
- severely, various of the calculational techniques in the Study as well as its lack of clarity.
The Review Group cited the following as major achievements of the study:
"WASH-1400 was a substantial advance over previous attempts to estimate the risks of the nuclear option.
"WASH-1400 was largely successful in at least three ways; in making the study of reactor safety more rational, in establishing the topo1ogy of many accident sequences, and in delineating procedures through which quantitative estimates of the risk can be derived for those sequences for which a data base exists.
"Despite its shortcomings, WASH-1400 provides at this time the most complete single picture of accident probabilities associated with nuc1ear reactors.
The fault-tree/event-tree approach coupled with an adequate data base is the best available tool with which to quantify these probabilities.
"WASH-1400 made clear the importance to reactor safety dis-cussions of accident consequences other than early fatalities."
The Commission accepts these findings and takes the following actions:
Executive Summary:
The Commission withdraws any explicit or implicit past endorsement of the Executiv'e Summary.
The Peer Review Process:
The Commission agrees that the
~peer review process followed in publishing WASH-1400 was inadequate and that proper peer review is fundamental to making sound, technical decisions.
The Commission will take whatever corrective action is necessary to assure that effective peer review is an integral feature of the NRC's risk assessment program.
Accident Probabilities:
The Commission accepts the Review Group Report's conclusion that absolute values of the risks presented by WASH-1400 should not be used uncritically either in the regulatory process or for public policy purposes and has taken and will continue to take steps to assure that any such use in the past will be corrected as appropriate.
In particular, in light of the Review Group conclusions on accident probabilities, the Commission does not regard as reliable the Reactor Safety Study's numerical estimate of the overall risk of reactor accident.
Communication with the Congress and the Public:
Commission correspondence and statements involving MASH-1400 are being reviewed and corrective action as necessary will be taken.
I
With respect to the component parts of the Study, the Commission expects the staff to make use of them as appropriate, that is, where the data base is adequate and analytical techniques permit.
Taking due account of the reservations expressed in the Review Group Report and in its presentation to the Commission, the Co;,mission suppo. ts the extended use of probabilistic risk assessment in regulatory decisionmaking.
The Commission has provided additional detailed instructions to the NRC-staf concerning continued use of risk assessment techniques and results in response to spec',fic criticisms raised by the Risk Assessment Review Group.
NOTES J2
/
Its charter reads:
"The Review Group will provide advice and information to the Commission regarding the final report of the Reactor Safety Study, WASH-1400, and the peer corznents on the Study, advice and recommendations on developments in the field of risk assessment methodology and on future courses of action which should be taken to improve tnis methodology and its application.
This advice and information will assist the Commission in establishing policy regarding the use of risk assessment in the regulatory process, in improving the base for the use of such assessments.
It will also clarify the achieve-ments and limitations of the Reactor Safety Study."
The other members were Dr. Robert J.
Budnitz (Lawrence Berkeley Laboratory, University of California), Dr. Herbert, J.
C. Kouts (Brookhaven National Laboratory),
Dr. Walter -Loewenstein (Electric Power Research Institute),
Dr. William Rowe (Environ-mental Protection Agency), Dr. Frank von Hippel (Princeton University) and Dr. Fredrik Zachariasen (California Institute of Technology).
Dr. Budnitz is presently on leave from the University of Californ',a and is serving (since August 1978) as Deputy Director of the NRC's Office of Nuclear Regulatory Research.
3/
The Nuclear Regulatory Commission was established on January 19, 197S to carry out the regulatory functions of the Atomic Energy Commission, which was abolished on that date.
4/
The press release at the time of publication said that the report is "the culmination of the most comprehensive risk assessment of nuclear power plants made to date.
The objectives of the study were to make a realistic assessment....
The overall conclusion...is that the risks attached to the'operation of present day nuclear power plants are very low compared to other natural and man-made risks....
Nuclear power plants are about 10,000 times less likely to produce fatal accidents than man-made non-nuclear activities....
Ron-nuclear accidents involving comparable large dollar va] ue damage are about 1,000 times more likely than nuclear power plant accidents....
The chance that a person living in the general vicinity of a nuclear power plant will be fatally injured in a reactor accident is one in five billion per year....
In the event of an unlikely reactor accident with a probability of one in a million per reactor per year, latent health effects except for thyroid nodules would be
'uch a small percentage of the normal incident rates that they would be difficult to detect...."
The NRC Chairman was quoted as saying, "The Commission believes that the Reactor Safety Study Report provides an objective and meaningful estimate of the public risks associated with the operation of present day light water reactors in the United States....
The final report is a soundly based and impressive work.. "
Its overall conclusion is that the risk attached to the operation of nuclear power plan s is very low compared with other natural and man-o ade risks."
The press release went on to say that more than 1800 pages of comments were received from a broad spectrum of people and a'Il were carefully considered in preparing the final repor t.
5/
Professor Lewis, in reporting to the Commission, said that the Executive Summary was not a summary of the report.
He concluded it was written as a public statement that reactors we> e safe compared to other risks to which the public is exposed and he stated it should not have been attached to the report and described as a part of it.