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NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competencies and with regard for appropriate balance.
This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine.
This report and the study on which it is based were supported by Contract No. NRC-04-94-055 from the U.S. Nuclear Regulatory Commission.
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COMMITTEE ON APPLICATION OF DIGITAL INSTRUMENTATION AND CONTROL SYSTEMS TO NUCLEAR POWER PLANT OPERATIONS AND SAFETY
DOUGLAS M. CHAPIN (chair),
MPR Associates, Alexandria, Virginia
JOANNE BECHTA DUGAN,
University of Virginia, Charlottesville
DONALD A. BRAND,
NAE, Pacific Gas and Electric Company (retired), Novato, California
JAMES R. CURTISS,
Winston and Strawn, Washington, D.C. (from October 1995)
D. LARRY DAMON,
Bechtel Research and Development, San Francisco, California
Federal Aviation Administration, Seattle, Washington (from October 1995)
JOHN D. GANNON,
University of Maryland, College Park
ROBERT L. GOBLE,
Clark University, Worcester, Massachusetts
DAVID J. HILL,
Argonne National Laboratory, Argonne, Illinois
PETER E. KATZ,
Calvert Cliffs Nuclear Power Plant, Lusby, Maryland
NANCY G. LEVESON,
University of Washington, Seattle
CHRISTINE M. MITCHELL,
Georgia Institute of Technology, Atlanta
General Atomics Company, San Diego, California
JAMES D. WHITE,
Oak Ridge National Laboratory, Oak Ridge, Tennessee
TRACY D. WILSON, study director,
Board on Energy and Environmental Systems (BEES)
SUSANNA E. CLARENDON, senior project assistant,
BEES (from May 1996)
THERON FEIST, project assistant,
BEES (until June 1995)
HELEN JOHNSON, administrative associate,
BEES (until July 1995)
WENDY LEWALLEN, senior project assistant,
BEES (June 1995 to May 1996)
MAHADEVAN MANI, associate executive director,
Commission on Engineering and Technical Systems (from January 1996)
JAMES J. ZUCCHETTO, director,
BEES (from January 1996)
BOARD ON ENERGY AND ENVIRONMENTAL SYSTEMS
ROBERT L. HIRSCH (chair),
Energy Technology Collaborative, Inc., Washington, D.C.
RICHARD MESERVE (vice chair),
Covington and Burling, Washington, D.C.
JAN BEYEA, Consultant,
New York, New York
E. GAIL de PLANQUE,
LINDA C. DOLAN,
Lockheed Martin Electronics and Missiles, Orlando, Florida
University of Tennessee, Knoxville
TASC, Inc., Arlington, Virginia
ROY S. GORDON,
NAS, Harvard University, Cambridge, Massachusetts
FRANCOIS E. HEUZE,
Lawrence Livermore National Laboratory, Livermore, California
LAWRENCE T. PAPAY,
NAE, Bechtel Group, Inc., San Francisco, California
RUTH A. RECK,
Argonne National Laboratory, Argonne, Illinois
NAE, Lutron Electronics Co., Inc., Coopersburg, Pennsylvania
JAMES LEE SWEENEY,
Stanford University, Stanford, California
IRVIN L. WHITE,
UTECH, Inc., Fairfax, Virginia
Former Members Active during Reporting Period
H.M. (HUB) HUBBARD (chair),
Pacific International Center for High Technology Research (retired), Honolulu, Hawaii
ROBERT D. BANKS,
World Resources Institute, Washington, D.C.
ALLEN J. BARD,
NAS, University of Texas, Austin
DAVID E. DANIEL,
University of Texas, Austin
NAE, Cornell University, Ithaca, New York
Liaison Members from the Commission on Engineering and Technical Systems
RICHARD A. CONWAY,
NAE, Union Carbide Corporation, South Charleston, West Virginia
New England Aquarium, Boston, Massachusetts
JAMES J. ZUCCHETTO, director (since January 1996)
SUSANNA E. CLARENDON, administrative assistant
WENDY LEWALLEN, senior project assistant (until May 1996)
JILL WILSON, senior program officer
TRACY D. WILSON, senior program officer
The nuclear industry and the staff of the U.S. Nuclear Regulatory Commission (USNRC) have worked for several years on how best to safely introduce digital instrumentation and control systems into nuclear power plants. But together they have failed to reach consensus. This lack of consensus led the USNRC to request the National Research Council, through its Board on Energy and Environmental Systems of the Commission on Engineering and Technical Systems, to conduct the study whose results are reported here. The National Research Council's Computer Science and Telecommunications Board and the Council's Division on Education, Labor, and Human Performance provided additional technical support.
The Committee on Application of Digital Instrumentation and Control Systems to Nuclear Power Plant Operations and Safety (see Appendix A) was appointed by the National Research Council on December 20, 1994, to examine the use of digital instrumentation and control systems in nuclear power plants. This work was to be conducted in two phases. The final report summarizes the work of both Phase 1 and Phase 2.
In Phase 1, the committee was charged to define the important safety and reliability issues (concerning hardware, software, and human-machine interfaces) that arise from the introduction of digital instrumentation and control technology in nuclear power plant operations, including operations under normal, transient, and accident conditions. In response to this charge the committee identified eight key issues associated with the use of digital instrumentation and control (I&C) systems in existing and advanced nuclear power plants. The eight issues separate into six technical issues and two strategic issues. The six technical issues are: systems aspects of digital I&C technology; software quality assurance; common-mode software failure potential; safety and reliability assessment methods; human factors and human-machine interfaces; and dedication of commercial off-the-shelf hardware and software. The two strategic issues are the case-by-case licensing process and the adequacy of the technical infrastructure. The committee recognizes that these are not the only issues and topics of concern and debate in this area. Nevertheless, the committee considers that developing consensus on these key issues will be a major step forward and accelerate the appropriate use and licensing of digital I&C systems in nuclear power plants.
In Phase 2 of the study, the committee was charged to identify criteria for review and acceptance of digital instrumentation and control technology in both retrofitted reactors and new reactors of advanced design; to characterize and evaluate alternative approaches to the certification or licensing of this technology; and, where sufficient scientific basis exists, recommend guidelines on the basis of which the USNRC can regulate and certify (or license) digital instrumentation and control technology, including means for identifying and addressing new issues that may result from future development of this technology. Where insufficient scientific basis exists to make such recommendations, the committee was to suggest ways in which the USNRC could acquire the required information.
In carrying out its Phase 2 charge, the committee limited its work to those issues identified in Phase 1. Further, the reader should not form too literal an expectation that the committee has provided a cogent set of principles, design guidelines, and specific requirements for ready use by the USNRC to assess, test, license, and/or certify proposed systems and upgrades. Rather, the results of the committee's efforts are presented in the form of conclusions and recommendations related to each key issue and primarily addressed to the USNRC for their consideration and use for setting detailed licensing criteria and guidelines for digital I&C applications in nuclear power plants. The report discusses the difficult and complex nature of the key issues and directions for developing consensus on assessment of digital technology. The committee outlined criteria where it was possible to do so but focused primarily on (a) process both in developing guidelines and in the short-term acceptance of new technology; (b) identifying promising approaches for further actions by the USNRC beyond the committee's report; (c) suggestions for avoiding dead-ends; and (d) mechanics
for improving communication and strengthening technical infrastructure at the USNRC. To carry out its work, the committee held a number of meetings, including site visits to several power plant facilities and simulators (see Appendix B). The committee also held detailed discussions with members of the staff of the U.S. Nuclear Regulatory Commission, the Nuclear Safety Research Review Committee, the Advisory Committee on Reactor Safeguards, members of the U.S. and foreign nuclear industries, and representatives from other safety-critical industries, who provided a variety of perspectives and information on digital instrumentation and control technology and its regulation. The committee is grateful to the many individuals who provided technical information and insights on this topic during briefings and site visits.
The chairman is also particularly grateful to the members of this committee who worked diligently and effectively on a very demanding schedule to meet a very difficult charge and produce this work. Special commendation and thanks are also extended to Tracy Wilson of the staff of the National Research Council, who was a pillar of strength and whose never failing energy and focus greatly facilitated the work of the committee.
Douglas M. Chapin