ML20206R848
| ML20206R848 | |
| Person / Time | |
|---|---|
| Issue date: | 10/27/1997 |
| From: | Holahan G NRC (Affiliation Not Assigned) |
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| NUDOCS 9905210002 | |
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i International Conference on Environment and Nuclear Energy Washington, DC - October 27-29,1997 This is a preprint (draft) of a paper intended for publication in ajournal or proceedings.
Since change may be made before publication, this preprint (draft) is made available -
with the understanding that it will not be cited or reproduced without the permission of the author.
NUCLEAR ENERGY, PAST, PRESENT, AND FUTURE Gary M. I!olahan Direc' tor, Division of Systems Safety and Analysis U.S. Nuclear Regulatory Commission l
Washington, DC 20555
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" Atomic energy is capable of applications for peaceful as well as military purposes."
With this pronouncement, the Congress, in the preamble to the 1954 Atomic Energy Act, released atomic energy (nuclear energy) from its military origins. The Congress also set out a new purpose for this new energy source...to serve and improve the " general welfare" of the country. The intent of the act was clearly broad and substantial,"to provide for...a program to encourage widespread participationin the development and utilization of atomic energy for peaceful purposes."
Those original goals have been fulfilled only to a modest extent. Medical and a few industrial applications of nuclear byproducts have become a normal part of our modern society. The role of radiation in medical diagnostics and treatments has been accepted, if not welcomed. In some sense, nuclear medicine is seen as no better and no worse than other medical procedures and is clearly preferable to the diseases it addresses. With respect to -
commercial power plant applications, nuclear energy has not been integrated into the electrical energy production mix of the nation in the same way. The public does not see nuclear power plants asjust one more way of producing electricity. The issues are seen as different, special, and of greater concern.
In order to address any potential role that nuclear energy could play in the future, it is lirst necessary to consider its past and its present, in terms of both our best technical understanding and in terms of public perception and acceptance. I will address these issues from the viewpoint of the regulatory agency; first the Atomic Energy Commission (the AEC) and now the Nuclear Regulatory Commission (the NRC).
Any future nuclear power plants; must be safe and environmqntally acceptable by the best technical assessments available (including reactor operation; decommissioning;and waste disposal);must be perceived as safe and environmentally acceptable by the public; and must be economically competitive. I will limit my remarks to issues relating to nuclear reactor operations.
Before the 1960's, nuclear reactors were in an experimental or developmental stage.
Fuel performance was ancertain and several partial or total core failures were experienced.
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Accidents at EBRI (1955), Chalk River (1952 and 1958), SLI (1961) were among those occurring at experimental reactors. This experience is not unlike the early experience in other developing technologies. Demonstration projects tested new approaches: pressurized-water reactor (PWR); boiling-water reactor (BWR); sodium-cooled reactor; gas-cooled reactor; and organically cooled and moderated reactor. Some worked well, others didn't. The public w's a largely unaware and uninterested. Government institutions and activitics were generally trusted and supported.
Ilowever, by the early 1960's a first generation of small commercial nuclear power plants were being put in place: Dresden 1, Big Rock Point,ilumboldt Bay, Indian Point 1, and Yankee Rowe among others. These plan's were all small by modern standards. They also lacked a common set of safety standards. The major safety issue of the 1960's became the need for a reactor containment building and the primary safety issue of the early 1970 became the need for an emergency core cooling system (ECCS). New rules were written and new safety standards put in place. The General Design Criteria (10 CFR Part 50, Appendix A) are the most conspicuous example of those safety standards. With these new and clearer safety requirements in place for core design, thermal hydraulic performance, ECCS capability and containment capability, the reactor designers began to develop larger and larger plants, constrained more by the industrialcapability of manufacturinglarge components than by any safety or regulatory considerations. With no clear end !.n sight for proposed power levels, the regulatory agency set a somewhat arbitrary limit corresponding to about 1300 MWe as a maximum licensable power level. At that point, five U.S. companies were actively designing nuclear reactors and. numerous utility companies were eagerly buying them. While these
" maturing" steps were being taken in the area of nuclear power plant design, the nation as a whole was loosing its confidence in government and corporate institutions.
In hindsight,with a fuller appreciationof: probabilistic risk assessment techniques; of operating experience; and of human performance, the risks from operation of these power plants seems substantially higher than for current plants, yet both the government and the public were more accepting of them.
In 1974 the first comprehensive Probabilistic Risk Assessment for nuclear power plants was published by the AEC in the "Rgtor Safety Study" commonly called "WASil-1400."
It fresented the first full picture of the risks of operation for a typical PWR and a typical BWR. Although criticized as " inscrutable" and incomplete, WASil-1400 presented reactor safety insights in a scientifically consistent and coherent manner. For the first time the designers,the operators,the public,and the regulator could see what was truly important and what was unimportant with respect to public health and safety. This was the first opportunity to introduce a regulatory approach which was more directly related to perceived risks. That opportunitywas missed. The combination of: technicalcriticism;immaturityof techniques; limited operationaldata; a focus on plant licensing; and operational events put WASii-1400 in the background.
In 1975, the worst fire in U.S. nuclear power plant experience ccurred at the Browns Ferry plant. That fire pointed out a significant weakness in their existing regulatory requirements. Resolution of the fire protection concerns resulted in several years of contentiousargumentsbetween the licensees and the NRC. The resulting fire protection rule (10 CFR 50.48)resulted in a significant improvement in fire protection but has been seen as overly prescriptive (i.e. infiexible)in its approach and not completely focused on addressing public health and safety issues.
4 performing better than at any time in the past as measured by the NRC Performance Indicators or by those of the Institute for Nuclear Power Operations (INPO) but some individual licensees performance has been of concern and has called for additional regulatory attention.
In 1996, there were 5 U.S. plants among the top 10 nuclear power plants in the world with respect to overall capacity; and 23 among the top 50. Yet economic pressures has forced several U.S. plant closures before the completion of the plant's design life.
The NRC has established clear regulatory processes for nuclear power plant standard design certification and identified increased safety expectatiors. In the NRC's Strategic Plan (NUREG 1614, Vol. 1), the Commission has established a strategy to "-give priority attention for license renewals, standard and advanced reactor design, early site approvals and new reactor licenses." It has gone on to review and approve two new standard designs (the evolutionary PWR design, ABB/CE System 80+ and the advanced BWR, GE's ABWR) and is currently reviewing an additional advanced design (the Westinghouse advanced PWR, AP-600). With respect to Probabilistic Risk Assessment, the current NRC initiative which NRC's Chairman Jackson has dubbed " Risk Informed Regulation,"is the strqest attempt yet to reform the regulatory process to assure that it is focused on those issues mort directly related to public health and safety. The NRC recently issued for public commerit, ten guidance documents which define the essential safety principles and expectations associated with a Risk-Informed Regulatory approach. Several pilot projects are also underway. As a i result of these activities the NRC expects to: improve safety decision making; make better use of NRC staff resources; and to reduce unnecessary burden on NRC licensees.
The current regulatory environment can be summarized as follows. The NRC is prepared to review, approve, and license new designs which have been shown or can be shown to meet modern safety requirements. The NRC is prepared to, and is in fact already at work, reforming regulatory requirements to focus them better on public health and safety issues and to provide added implementing flexibility where and to the extent practical. The NRC has an effective program for monitoring operational performance and will acknowledge good performance and respond efrectively to poor performance. The technical safety issues relating to continued operation of current plants and the licensing of future evolutionary or advanced designed can be sufficiently met to allow continued or even increased used of nuclear power.
The more difficult issues of: public perception of safety, public acceptance of nuclear options; and economic feasibility are likely to be the real deterrnining factors in any future for the nuclear power option in the U.S. With respect to public acceptance of nuclear power, two conditions are necessary(although they may not be sufficient). They are: 1) Long term safe operation orcurrent plants and,2) credible open, and independent regulatory oversight which -
is responsive and understandable to the public.
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On March 28,1979, the TMI-2 accident occurred and the future of nuclear power in the U.S. would be changed forever. The messages from that accident were clear and unmistakable: 1) severe accidents leading to core damage were a real concem, and could no longer be treated as remote, hypothetical,and unrealistic;2) the importance of the defense-in-depth philosophy was re-confirmed; 3) neither the licensees nor the NRC was prepared'to respond effectively to a severe accident;4) the human factors and human performanceaspects of reactor safety were very important yet had been largely overlooked; 5) the actual operating experience of nuclear power plants had been ineffectively monitored by both the NRC and the nuclearindustry. The TM1 Action Plan of over 170 new requirements was synthesized from the numerous accident studies. In addition, the NRC's Commission Policy Statements on Safety Goals and on Seveie Accidents were direct attempts to recognize the importance of /
severe accidents and to address them in several practical ways.
One of the most significant of the M2 a:cident studies was the so called "Rogovin Report" initiated by the Nuclear Regulatory Cuum msion. In addition to its direct contribution to the insights listed above, the Rogovie R: port represented the second opportunity to ,
introduce Probabilistic Risk Assessment (PRA) techniques directly into the regulatory process. ;
its recommendations in this area are clear.
" Mon. rigorous and quantative methods of risk analysis have been developed and should be employed to assess the safety of design and operation.
The best way t.o improve the existing design review process is by relying in a major way upon quantative risk analyses..."
This second opportunity was only partially fulfilled and only afler several years, in 1988 the NRC issued a request to the licensees of nuclear power plants to voluntarily perform l
a self assessment (the " Independent Plant Evaluations"(IPE's)) using PRA techniques (or their l
equivalent). As valuable as the IPE's have been, they were not the change in regulatory l approach envisioned in the Rogovin Report. i The 1980's were largely a reactive time in which safety improvemerts were required in numerous areas. The safety requirements added to plants in the years since their original licensing (i.e.,in the 1970's,1980's,and early 1990's) include: the TMI Action Plan items;the ECCS rule (10 CFR 50.46); the Emergency Planning Rule (10 CFR 50.47); the Fire Protection Rule 10 CFR 50.48); the Electrical Equipment Qualification Rule (la CFR R49); the Anticipated Transients With,out Scram (ATWS) Rule (10 CFR 50 62); the Presserized Thermal Shock (PTS) Rule (10 CFR 50.61); and the Station I'lackout (SBO) Rule ;
10 CFR 50.63). In addition, numerous other requirements were put olace through o her safety initiatives in response to operational events. .
l As a time ofincreasing requirements, increasing costs, and sloping growth in electrical energy demands,the 1980's were not encouragingto utilities thinking about adding electrical production capacity. The utilities which were operating nuclear power plants concentrated on improving operations and have been very successful at increasing capaci'y of thei. pbts while reducing the number and severity of events. The nuclear power plant designers became largely service companies for the short term and began to look toward standard evolutionary or advanced designs for the more distant future (and for foreign markets). l And where is nuclear power now in the 1990's? Operating plants are gensrally