Programs for the collection and analysis of statistical data initiated in 1979 addressed the reliability of nuclear plant operators, maintenance personnel, and a wide variety of safety-related components. Data on equipment failures and human errors were drawn from licensee event reports, power plant log books, and the records in the Nuclear Plant Reliability Data System data banks. The data were analyzed to estimate average error or failure rates; check the consistency of the data sources; identify trends or patterns in the data (time trends, variations from plant to plant, etc.), and study multiple failures of common cause. Work continued on a handbook describing the principal factors governing the reliability of nuclear plant operators to serve as a guide to safety analysts and risk assessment practitioners in assessing human error contributions to risks.

Research to Improve
Reactor Safety

An amendment (P.L. 95-209) to the Energy Reorganization Act of 1974 directs NRC to "develop a long-term plan for projects for the development of new or improved safety systems for nuclear power plants" and requires that the plan be updated annually and submitted to the Congress. The Congressional intent behind this effort is "the improvement of reactor safety and not the enhancement of the economic attractiveness of nuclear power versus alternative energy

sources.

In April 1978 NRC submitted to Congress a "Plan for Research to Improve the Safety of Light-Water Nuclear Power Plants" (NUREG-0438), which presented an evaluation of concepts proposed to improve safety and recommended a three-year, $14.9 million research program. The objectives are to determine the feasibility of achieving particular improvements in safety, to evaluate the safety significance of proposed changes and to propose regulatory requirements where implementation is determined to be desirable, without preparing detailed designs. Five research topics and two general studies were suggested:

Alternate containment concepts-especially vented containments-to mitigate the consequences of postulated core meltdown accidents. This is accomplished by improving control of the release of radioactivity to the environment.

Alternate decay heat removal concepts-especially add on, bunkered systems-to reduce the probability of core meltdowns by increasing the reliability of systems designed to remove heat from the reactor core after fission ceases.

Alternate emergency core cooling concepts-to develop simpler and more clearly demonstrable systems to prevent fuel overheating in the event of pipe rupture.

Improved in-plant accident response-to reduce the risk from human error by enhancing the quality of the operator-machine interface and by helping operators make correct decisions during accidents.

Advanced seismic design—to reduce the vulnerability of plants to earthquakes by decoupling or strengthening components against seismic forces.

Scoping studies of other concepts to determine their potential for improving safety and to assess the need for further research. The studies address protection against sabotage, better ways to monitor the condition of the plant, new siting concepts and ways to reduce occupational exposure without increasing public risk.

Improved evaluation methodology-to assist in making more rigorous and thorough assessments of the values and impacts associated with these concepts, and in planning future safety research programs.

Operating experience accumulated since NUREG-0438 was issued, including the events at Three Mile Island in March 1979, reinforces the judgments expressed therein. Many individuals and organizations have submitted additional recommendations for improving safety since TMI, and these also tend to support the original judgments, especially the high priorities assigned to improved in-plant accident response, alternate containment concepts and alternate decay heat removal systems. Within the high priority areas, research toward enhancing the capabilities of reactor operators and improving the quality of the operator-machine interface has been accelerated.

In fiscal year 1979 Congress authorized the expenditure of $1,500,000 to implement the research plan, but appropriated no funds for the purpose. To accommodate this mismatch, the Commission sought and received from Congress reprogramming approval in two separate actions totaling $800,000. The time required to complete these actions delayed the initiation of technical work until the latter half of the fiscal year. Furthermore, the reduced amount of funds made it necessary to restrict studies to a few specific concepts judged to have the highest potential for risk reduction. These factors are reflected in the limited results reported here.

In 1979 research focused on improved in-plant accident response, vented containment, and add-on decay heat removal systems. The status and direction of programs underway at the end of the fiscal year are summarized below.

Improved In-Plant Accident Response

A study was initiated at Idaho National Engineering Laboratory to identify the information required by an operator to determine unambiguously the status of his plant. Accident sequences having relatively high probabilities of leading to core damage are being analyzed to identify how the plant might respond and what measurements are needed to accurately and uniquely characterize that response. The study indicates what range of physical parameters should be measurable and for which parameters direct measurement might be preferable to indirect measurement. The results are helping establish regulatory positions regarding instrumentation required to monitor the course of an accident. They are also useful in determining what data might be transmitted to remote monitoring and technical support centers.

The simultaneous influx of alarms and data during a reactor accident can overwhelm even a well-trained, experienced operator. A potential solution lies in the application of computer technology to the diagnosis of plant disturbances. Oak Ridge National Laboratory is reviewing the state-of-the-art in computerized disturbance-analysis systems and audio-visual displays with a view toward transferring the applicable technology to nuclear plants.

Oak Ridge is also examining key aspects of the technical basis for disturbance analysis systems, including the reliability of the hardware and software and the quality of the plant systems analysis. These insights will enable the NRC to establish regulatory requirements and to evaluate related efforts by the nuclear industry.

Planning for a conference jointly sponsored by the NRC and the Institute of Electrical and Electronics Engineers was initiated in fiscal year 1979 to identify the extent to which technology from aerospace, defense and other industries may be useful in these NRC programs.

Alternate Containment Concepts

Risks to the public from nuclear reactor accidents are dominated by sequences in which the core melts and the containment ruptures above ground level because of overpressurization. Concepts have been proposed which would reduce the pressure in the containment during accidents while channeling the containment atmosphere through filter media to retain the radioactive materials it might contain.

In a Sandia Laboratories investigation of the technical feasibility and risk reduction potential of these systems, the state-of-the art in containment design and filter technology has been surveyed and incorporated into a program plan. Conceptual designs fitting vent filter systems to several existing containment types are being developed, and computer codes to analyze their effectiveness are being modified

as necessary. The goal is to propose regulatory requirements for vent filter systems and to assess the values and impacts of their implementation on existing and future reactors.

Alternate Decay Heat Removal Systems

After the nuclear chain reaction in a power reactor ceases, residual heat produced by the decay of radioisotopes must be removed over an extended period of time. This is the function of decay heat removal systems. Improvements in the reliability of these systems offer relatively high potential for risk reduction.

A study was initiated at Sandia Laboratories to identify ways to enhance that reliability and to quantify the risk reduction potential inherent in such improvements. The study includes review of existing criteria for the design of decay heat removal systems and estimates of the resulting reliability. Preliminary performance and safety design requirements are being generated to guide the development of detailed designs by the Department of Energy. The reliability of the improved system will be estimated and the information used to identify the need for and nature of revised regulatory requirements.

Improved Methodology

Assignments of priorities for safety research and decisions on the adoption and implementation of regulatory positions require judgments regarding the values and impacts of alternatives. A study was initiated at Pacific Northwest Laboratory in conjunction with Battelle Columbus Laboratory to develop more objective and precise methods for making value/impact assessments. Initial emphasis is on better ways to quantify the risk reduction potential of proposed changes in design or operation. Longer term activities include improving the methods used to address the uncertainty in risk estimates and to integrate risk reduction potential with other values and impacts affecting a decision. The results would also pertain to activities beyond the scope of the improved safety research, such as confirmatory research and adoption of regulatory standards.

No work was initiated to study containment concepts other than vented containment or decay heat removal concepts other than a dedicated add-on system. No work was initiated to investigate advanced seismic designs or alternate emergency core cooling concepts. These are being deferred pending the outcome of confirmatory research on the effectiveness of current designs. Needs for research on concepts other than those identified above (e.g., protection against sabotage, improved techniques for nondestructive examination, improved emergency planning, reduced occupation exposure) are being reviewed continually

by the NRC staff within the context of confirmatory research and the development of requirements by the regulatory staff. Such needs will be addressed in 1980 and beyond, as resources allow.

In addition to conducting its own research, NRC has provided guidance to the DOE regarding its efforts to improve reactor safety, including recommendations that DOE initiate more detailed examinations and

design studies on computerized disturbance analysis techniques, vented containment, hydrogen control technology, add-on decay heat removal systems and seismic decoupling. In addition, NRC asked DOE to take the lead in assessing the cost impacts of design improvements, including implications for retrofit. This cooperation should ease the transition of new concepts into commercial application.

Many actions are taken annually by the NRC to inform the public directly and to make information available regarding nuclear regulation. These take the form of public announcements and Federal Register notices; publication of staff and contractor reports; providing access to documents in localities across the country; holding meetings and workshops with public, State and local representatives on issues of widespread interest; responding to public and Congressional inquiries; opening to public observation Commission, staff and advisory committee meetings; and many public hearings on rulemaking and licensing.

Members of the Commission and the NRC staff also participate in press conferences and public meetings and, where special interest warrants, testify before committees of the Congress.

As the most direct means of communicating to the public, the NRC issues announcements on a wide range of topics from headquarters and the five regional offices to some 5,000 members of the news media, industry, the scientific community and the general public.

Making Documents Available

The NRC maintains its principal Public Document Room (PDR) at 1717 H Street, N.W., Washington, D.C., and has established more than 130 public document rooms throughout the country. The local PDRS are typically located in libraries in cities and towns near proposed and actual nuclear plant sites, and contain detailed information specific to the nearby facilities which are either licensed or under regulatory review. (See Appendix 3 for a list of all local PDRs.) NRC currently makes publicly available through its main PDR in Washington approximately 320 new documents each day. The main PDR contains about 880,000 documents in hard copy or in microfiche. These documents pertain to the licensing of source

material, production and utilization facilities, special nuclear material, transportation of radioactive materials, nuclear exports and imports, research and technical assistance reports, reports on generic technical issues, rules and regulations, Commission correspondence, transcripts of Commission meetings, minutes and reports of NRC's advisory committees and other material relating to the responsibilities and operation of the Commission.

The PDR services a diverse clientele. About 42 percent of its users are from industries directly affected by the Commission's activities (utilities, vendors, insurers, manufacturers), 12 percent from companies peripherally affected, 9 percent from law firms, and 37 percent from educational institutions, media, congressional and Federal agencies, public interest groups, and private citizens.

Members of the public may visit the PDR and examine any document in the facility, which furnishes reference assistance, copying services, and micro-fiche reader/printers. In fiscal year 1979, an on-line bibliographic retrieval system was designed and installed in the main PDR to increase accessibility to NRC information. During an average month in the report period, visitors to the Washington PDR requested access to about 7,000 files. The PDR staff also responded to an average of 90 letters a month. More than 1.7 million pages of documents and 13,500 microfiche cards were reproduced for the public during the year.

NRC publishes a Daily Accession List providing a bibliographic description of the documents placed in the PDR. A copy of this list may be obtained by writing the Division of Technical Information and Document Control. The PDR also provides limited free distribution of press releases and Commission/Board orders and issuances.

The NRC's main Public Document Room (PDR) in Washington, shown here, contains about 880,000 documents and makes available to the public more than 300 new documents per day. Members of the public are encouraged to visit the PDR, which offers reference, copying and reader/printer services.

TMI-2 Investigation Center. In the aftermath of the accident at Three Mile Island Unit 2 (TMI-2), Senator Gary Hart, Chairman of the Subcommittee on Nuclear Regulation of the Committee on Environment and Public Works, initiated an investigation into the event. To support this special investigation, Senator Hart requested NRC to provide facilities for access to all the documentation related to the accident and other information concerning other operating nuclear power plants of Babcock and Wilcox (B&W) design. On June 2, 1979, the Three Mile Island Documentation Investigation Center was established at the Commission's Washington, D.C., office. The NRC's Division of Technical Information and Document Control collected the documentation and staffed the center, which was also utilized by staff of the President's Commission on the Accident at Three Mile Island.

A pre-incident and post-incident file was established for all documentation concerning Three Mile Island Unit 2, including letters, memoranda, technical and safety analysis reports, pictures, engineering drawings, and depositions taken by investigators. Tapes of conversations between the NRC Operations Center and the TMI site and interviews of key participants were also made available.

The related information on the operating B&W facilities (Arkansas Nuclear One-Units 1 and 2, Crystal River, Davis-Besse, Rancho Seco, Oconee Units 1, 2,

en

and 3, and Three Mile Island Unit 1) included Preliminary Safety Analysis Reports, Final Safety Analysis Reports, Environmental Reports, Safety Evaluation Reports, inspection reports, reportable occurrences, monthly operating and annual vironmental reports. A complete set of B&W topical reports was also available in microfiche. Reference information included NRC Regulatory Guides, the nuclear power Standard Plan, and the results of extensive computer-generated bibliographic searches done on the Lockheed, RECON, and other energy data bases.

A sophisticated array of document management technology was made available to provide the investigators with prompt access to the large volume of documentation, which exceeded 2,000,000 pages. The Commission provided the investigators use of the NRC's automated Document Control System for online, computer-assisted searches of NRC documentation since 1978, and all TMI-related documents. In addition, a professional technical librarian and a technical information assistant handled investigators' requests for specific information.

Freedom of Information Act. The NRC continues to fulfill its obligation to make available records in its possession to interested members of the general public who request them under the Freedom of Information Act (FOIA). By making identifiable records available in all cases where the requested information is not exempt from production, the NRC is contributing to full and fair debate of public issues.

Some categories of records deemed exempt by the statute consist of documents properly classified under Executive Order 12065 (national security matters, trade secrets and commercial or financial information); some types of investigatory files; and certain interagency or intraagency memoranda of a pre-decisional nature.

The NRC continues to place material released in response to FOIA requests in the Headquarters Public Document Room, where the public will have full access. Additionally, documents released under the FOIA which pertain to a particular licensed facility or one under licensing review are furnished to the NRC Local Public Document Room serving that facility.

The number of FOIA requests received during fiscal year 1979 rose by 70 percent over 1978 to 503. This was due both to the public interest generated by the accident at Three Mile Island and growing public awareness and concern regarding various nuclear power issues. Some 16,800 staff man-hours were devoted to supplying requesters with information requested under the FOIA, and more than 80,000 pages of documents were released.

The Privacy Act of 1974. This law, which became effective in 1975, provides that individuals have the