Safety has always been a primary mandate of first the AEC then the NRC. It has been their responsibility under the Atomic Energy Act of 1954 to establish rules and regulations for the purpose of protecting the public from accidents involving nuclear power. At times this duty has conflicted with the assignment to encourage the development of the nuclear power industry, but at the same time the agency realized that nothing could be worse for the industry than a major accident with injuries or loss of life. A loss of coolant accident (LOCA) with a meltdown and breach of containment has always been a primary fear, particularly as the size of plants increased. The consensus of expert opinion was that such an accident was unlikely but the consequences of one were grave enough to warrant defense in depth to prevent it. As the size of plants increased so did the consequences of a potential LOCA. Concern was raised regarding the probability of a containment maintaining it integrity in the event of a severe accident. Academic theories of the probabilities and scenarios were replaced with facts and methods for dealing with actual events in March 1979 when the accident occurred at TMI 2. Events at TMI did not follow any of the theoretical models previously developed. Afterward it was necessary to reexamine a number of assumptions about the mechanism and results of various accident scenarios. The melting of over half the fuel in the reactor had not resulted in any breach of the containment, in fact the fuel had remained in the reactor vessel. The LOCA had not come about in the way most expected, the break of a large pipe, but through the failure of a pressure relief valve to close.

The NRC reexamined many of its regulations in light of the TMI experience, this included a requirement for licensees to prepare plans for beyond design basis accidents mitigation or prevention. Accidents of this sort, so called Class 9 Accidents, were believed to be so improbable as to be incredible prior to TMI 2. Notice was given of the proposed change in October of 1980. Over the course of the next two years the NRC staff backed away from the majority of their previous proposals, perhaps as a response to industry concerns regarding the potential costs of retrofitting plants and complying with additional license requirements. Staff presented a proposal for a policy statement to the Commission in January 1982 that would require only compliance with an interim rule on hydrogen control by existing plants and those with construction permits. This plan was based on the results of probabilistic risk assessments (PRA) which indicated that risk estimates for severe accidents in existing plants had been overstated. Commissioners were wary of placing too much credence in PRAs which they were not certain were reliable but approved of making a policy statement rather than a rulemaking. Staff made certain revisions and returned in July with a proposal that put less emphasis on PRAs but retained the basic premise that existing plants were safe the way they were or with a few minor changes. This proposal was opposed by the Advisory Committee on Reactor Safeguards (ACRS) who felt that it was not a realistic appraisal of the current state of safety at nuclear plants. The Commission split on the issue but approved publishing it for comment.

Industry not unexpectedly was of the opinion that current plants were far safer and more resilient than previously believed and produced a number of studies that they felt supported this position. Meanwhile further Loss of Fluid Tests were conducted at INEEL which tended to support the optimistic studies produced by industry. It was demonstrated that under extremely rigorous situations the ECCS still performed well in a scale model reactor. Another issue that required resolution was source term. This referred to the amount of radiation released in an accident, the source was the damaged reactor and the term the quantity of radiation released from it. Industry maintained that prior estimates of source terms had been greatly overstated, and that even the most severe accident envisioned would cause no radiation deaths and that existing regulations overestimated cancer deaths 100 times. They claimed that containment failure was practically impossible. These conclusions were supported by the Special Committee on Source Terms of the American Nuclear Society and were borne out by the TMI experience. NRC sponsored a study on the issue by the American Physical Society which argued for a more conservative view until further research could be done.

An additional source of controversy was how likely an accident was to occur. There existed a wide range of opinion concerning the potential frequency of accidents, despite this NRC voted to approve the policy statement on June 27, 1985. In it they asserted that "on the basis of currently available information the Commission concludes that existing plants pose no undue risk to public safety and property and sees no present basis for immediate action on generic rulemaking". In response to ACRS prodding the NRC agreed to examine individual plants for potential site specific circumstances that might affect the overall safety of the plant. The staff presented a plan to close out the safety issues in May 1988. In the proposed plan there would be development of recommendations for improving containments, examination of methods to limit human error as a factor, and individual plant examinations (IPEs) to determine site specific risk factors among other issues. The Commission approved a letter to licensees requesting the IPEs in October 1988. Staff finished work on the containment recommendations in January 1989 for the Mark I containment design used by GE and completed the other five by November 1991. A series of improvements were outlined for the Mark I, there were no improvements indicated for the remaining designs. Controversy over source terms continued as did research. In 1995 the NRC published an updated document on source terms bringing the closure of the severe accident question somewhat closer. To this point there remain outstanding issues to be resolved.

Prior to TMI 2 little attention was paid to emergency planning. In December 1970 the AEC issued a rule, Appendix E of 10 CFR Part 50, providing guidelines to licensees on what their emergency plans should address. In 1973 the AEC was designated lead agency for radiological emergency planning by the Federal Office of Emergency Preparedness. The AEC provided the states and localities with additional guidance on creating emergency plans for design basis accidents at nuclear installations. This guidance included a checklist of 154 items to be included in an effective plan. In 1977 the NRC pointed out 70 of these items it considered essential including information about drills and training. Responses from state and local governments made it clear that there remained a good deal of confusion on the part of their emergency management agencies as to what sort of accidents they should be planning for. NRC and EPA joined together to provide additional guidance and instruction. This was released in December 1978 in the form of a 120 page report. It introduced concepts that had not been previously included such as plume exposure pathways and ingestion pathways, and advised that Class 9 accidents also be considered.

A Government Accounting Office report released not long after concluded that licensees appeared to be prepared but that governmental agencies were much less so. Only 12 states had plans that met the NRCs guidelines and it was recommended in the GAOs report that the NRC issue licenses only in states who had acceptable emergency plans and that measures be instituted to better inform the public in the event of an emergency. Ironically, the report was issued on March 29, 1979 during the accident at TMI 2. The colossal muddle of misinformation and disarray that occurred during the accident brought about calls from all sides for improvement. in the aftermath, a number of changes were made to attempt to meet the demands imposed on NRC by Congressional Oversight Committees.

Legislation to make licensing of new plants contingent upon the existence of adequate emergency plans was defeated by those who feared that this approach would in effect give states veto power over proposed nuclear plants or possibly allow them to force the closure of existing plants. An NRC task force was formed to examine the issues surrounding emergency planning and produce recommendations, which were presented in August of 1979. A number of these concerned internal NRC policies and programs which could be immediately implemented, but two issues were deemed to require rulemaking. The Commission requested staff to investigate the emergency planning zones recommended in the joint NRC/EPA proposal and the issue of licensing being contingent upon approved plans. Staff expedited the inquiry and concurred with the Joint plan on zones which had been well received by the states. The issue of contingency was more difficult to resolve. NRC did not have authority to force recalcitrant states to participate in the planning process and Congress refused to extend it the ability to do so which it felt would be an infringement on states rights.

This left the NRC without a viable option and it therefore published a final rule in August 1980 granting existing plants a grace period, to expire April 1, 1981, to prepare an emergency plan in concert with the state which would meet guidelines to be established by the NRC in cooperation with the newly formed Federal Emergency Management Agency (FEMA). FEMA would be responsible for determining the adequacy of emergency plans for the areas surrounding the site while NRC would do the same for the plant site itself. Under this agreement the NRC would retain the prerogative to determine if each plan was adequate overall and either issue or refuse to issue permission allowing operation to continue. Indian Point Units 1 and 2, operated by Consolidated Edison produced controversy when the emergency plan was twice rejected by FEMA as inadequate in 1981 and 1982. The finding of deficiency was largely due to the refusal of Rockland County to participate. Eventually, the State of New York stepped in on behalf of the County and the resulting plan was approved in a split decision by the Commission. A review of the ruling on emergency planning was undertaken after the divisive battle over Indian Point and was still in process when similar acrimony arose over the Shoreham and Seabrook Plants.

The Shoreham Plant was to be located on Long Island and was vigorously opposed by local residents particularly after the accident at Chernobyl in April of 1986. Local government maintained that an effective emergency plan for the site was not possible and insisted that the location was untenable. New York State refused to intercede as it had at Indian Point despite the protests of Long Island Lighting Company. Seabrook was located in New Hampshire which had cooperated in emergency planning with Public Service of New Hampshire and FEMA to produce an emergency plan for the proposed plant. After Chernobyl, Massachusetts refused to cooperate in the plan and since areas of the 10 mile zone extended into Massachusetts the plants approval was threatened unless the NRC was willing to accept a reduced zone of 2 miles.

The re examination of the NRCs ruling on emergency plans had meanwhile reached the conclusion that a rule change was necessary and in February 1987 the staff and Office of General Counsel proposed specific revisions to the existing rule. These would allow the issuance of a license in cases where the utility had made a good faith effort to obtain State or County participation and had developed an emergency plan for the site that was deemed achievable by NRC and which would likely garner government cooperation in the event of an actual emergency. This policy was termed the realism doctrine and erupted into a massive furor pitting a number of Governors, Senators, and Representatives opposed to abrogating local control over power. The Commission voted unanimously to implement the rule with minor changes. In September 1988 the US Court of Appeals upheld the decision. In April 1989 the NRC granted an operating license to the Shoreham Plant, but under an agreement with the State, Long Island Lighting decided not to operate the plant. Seabrook received an operating license in March 1990 despite profound and dedicated opposition by local citizens and the State of Massachusetts.

In a sense safety is like beauty, in the eye of the beholder. It is possible to look at the record of the nuclear energy industry and draw a variety of conclusions from what you find there. The industry looks at the record and sees that no member of the public has ever been killed or directly injured by their activities, for this they pat themselves on the back. This of course discounts studies that attempt to link radiation exposure in small amounts to damage or injury later in life. It is difficult to prove a causal relationship between a small exposure and a cancer that does not appear for twenty years. On the other hand, it is possible to look at the record and come to the conclusion that nuclear energy poses a serious risk to those who live near or work at the plants. This latter opinion leaves aside fact that there is more than a kernel of truth to the industries claims for safety. The worst accident in US history in fact did not kill anyone, and no radiation escaped the plant. Industrial processes of all kinds have accidents, history is full of fertilizer explosions, grain elevator blow ups, coal mine fires and the like, no one calls for no more fertilizer plants or grain elevators. In the end you must determine if you expect the nuclear industry to be different than any other, they are not, and whether you expect the operators of nuclear facilities to be more like physicists or boiler operators.

Perhaps the initial expectations of the public, built upon the promises of the salesmen from government and industry who brought us nuclear power, were too high. Is perfection attainable? Even if it isn't, is it not worth trying to achieve? Have we been saved from worse accidents by skill...or luck? The following six accounts comprise the record of reactor accidents for both the commercial and governmental operators of nuclear facilities, in the US and abroad. Several are very widely known, having been much in the news when they occurred, others less so. Only two of these accidents took place in plants of the type used for power production in the United States; of the others, one was an experimental reactor, one a plutonium production pile, and one a duel purpose plant of a style only used in the former Soviet Union. The implications that can be drawn as far as the general safety of nuclear power are necessarily somewhat limited.