ML19344E594
| ML19344E594 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 08/15/1980 |
| From: | Eisenhut D Office of Nuclear Reactor Regulation |
| To: | Parris H TENNESSEE VALLEY AUTHORITY |
| References | |
| NUDOCS 8009020318 | |
| Download: ML19344E594 (4) | |
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Docket No. 50-259 August 15, 1980 Mr. Hugh G. Parris Manager of Power Tennessee Vality Authority 500 A Chestnut Street, Tower II Chattanooga, Tennessee 37401
Dear Mr. Parris:
Subject:
IREP Schedule At our meeting on August 4 we promised to send you an outline of the IREP schedule for the first 5 months annotated to highlight the skills and knowledge that could best be provided by your representative (s) on the IREP team. The anticipated start date is September 15, 1980. The following discussion refers to the IREP Procedure and Schedule Guide, to my letter of July 25, 1980.
First 2 weeks - First cut at tasks 1-5, late September. The team will be familiarizing itself with the plant documentation and perfonning the first few tasks in the IREP Procedure and Schedule Guide. We anticipate a number of document requests to be made from the procedure index or diagram index. Someone thoroughly familiar with the plant design and operations documentation wuld help the team to be selective and to reoJest the appropriate documents.
Third through eighth week - First cut at tasks 6-17, October and early November. The team will be classifying initiating events, developing the catalogs of accident scenarios in broad outline (event tree analysis),
defining system success vs. failure criteria, and tracing the possible causes of the initiating events to faults in the support systems which also serve the required mitigating systems. During this phase, the assistance of an individual who has a broad understanding of accident processes, systems design, and operation would be particularly valuable.
We have not requested the voluminous plant design documentation on power generation equipment that may prove to be necessary to perfonn the fault tree analyses of transient initiators and non-passive failure LOCAs.
Therefore, we will probably assign to the more knowledgeable owner's representative the lead responsibility for the development of the fault trees for the initiating events. He will also be expected to partici-pate in each of the other tasks: event tree analysis, definition of the system mecess vs. failure.:riteria, etc.
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Mr. Hugh G. Parris AUG 15 580
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Ninth through sixteenth week - First cut at tasks 18-27, late November through January.
This phase of the study will focus on fleshing out the reliability-predictive models of the systems (fault tree analysis). The visit to the plant by the team will occur late in the prior phase or early in this phase. We anticipate that the early work in this phase will concentrate on the relatively straight-forward front line engineered f afety features.
In the later phase the wrk will move to the modeling of the network of support systems. We expect a progressively gmwing need for owner's representative assistance to the team within this iaterval in the contexts of (1) surveillance and maintenance practices, (2) operating and emergency procedures, and (3) control and instrumentation.
Sixteenth through twentieth week - First cut at tasks 28-35, February.
The initial screening of accident scenarios according to likelihood and the search for not-yet-identified common cause failure modes will take place in this interval. Particularly useful knowledge and skills in your representatives will be in the areas of possible operator corrective action in the face of multiple failures, control and instrumentation, and procedures.
In this and successive phases the team will be refining their models of the potentially dominant accident scenarios. The questions the team will need to ask of your personnel will be more sharply focused. The physical presence on the team of the more knowledgeable and valuable personnel will be less important than in the fomative second phase (weeks 2-8).
You will, however, want to keep your more senior people in engineering and operations apprised of the emerging picture of the dominant accident sequences. You may want to intersperse the occasional management briefings with more frequent technical briefings during the last few months of the program.
From our point of i;ew, we would prefer z much continuity, knowledge, and skill as we can get in your participet:. We do understand, though, that your better people are in great demand.
If I were in your shoes and could manage it, I would assign a junior systems and licensing engineer or systems reliability engineer to stay with the IREP team throughout. He or she muld be in it for the experience, for liaison, and to take a prominent role in the digestion and use of the results at the conclusion nf the IREP study.
He or she might be eamarked to exercise and keep the IREP models updated after the NRC study is complete, as Florida Power Corporation is planning to do.
I would select that l
person for imagination, sound abstract thinking or broad overview, and at least a passing familiarity with mechanical, electrical and control j
systems engineering. That person should also have the facility with mathematics to rapidly learn probabilistic system reliability analysis t
while on the team.
In addition to this continuous presence on the IREP team, I would assign a couple of others for temporary assignment to IREP.
I would pick the most knowledgeable individual I could pry loose in plant operations and engineering for the 6 week second phase period
iir. Hugn G. Parris AUG 151980 in October and ibyenber (event trees, system success criteria, and the analysis of initiating events).
I tould try to earnark 1 day per v.eck of this same person's tice from February through the conclusion of the study - while he or she remains at their nomal post - to review the convergence on results. A third person, chosen for fantliarity with control and instrumentation, maintenance procedures and emergency proccdures would be detailed to IREP in January and February (late in the systen reliability codeling phase and the subsequent probabilistic evaluations) to assure that the rudeling of the network of support systens is done correctly, to participate in the evaluation of equipeent unavailability due to test and caintenance, and to assist in rudeling the possibilities for operator corrective action during accidents. That person, too, I would assign to part time review of IREP results after their return to nomal assign ent in ! arch. To nake sure that person can get up to speed pronptly when he or she joins the team in January, that person should have attended - as a minicum - an engincering short course in probabilistic systen reliability analysis or fault tree analysis.
This representation, one person full time and tin cure highly-oualified people for 6 week assignments should reet our mutual need to assure that the rudals produced in IREP fairly portray sur plant and offer pur people considerable experience in probabilistic safety analysis without unduly burdening your already hard pressed staff, or so we believe.
I hope that thh helps pu in pur planning for IREP participatics.
Sincerely, Ortginal signed by Darrell c. Zinenhut Darrell u. Eisenhut. Director Division of Licensing Office of !!uclear Reactor Regulation cc: See Attached List bcc: Dacket File flRC Public Document Room R. Clark R. Mattson M. Ernst S. Israel F. Pousome J. Murpny R. Berneru.
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H. S. Sanger, Jr., Esquire Mr. Robert Szalay, Licensing and Safety Project Manager General Counsel Atomic Industrial Forum Tennessee Valley Authority 7101 Wisconsin Avenue 400 Comerce Avenue Washington, DC 20014 E 118 33 C Knoxville, Tennessee 37902 Mr. E. P. O'Donnell Mr. Rnn Rogers Ebasco Services, Inc.
Tennessee Valley Authority 500A Chestnut Street. Tower II 89th Floor Chattanooga, Tennessee 37401 2 World Trade Center New York, NY 10048 Mr. H. N. Culver 249A H8D 400 Comerce Avenue Dr. Edwin Zebroski Tennessee Valley Authority Nuclear Safety Analysis Center Knoxville, Tennessee 37902 3412 Hillview Avenue P. O. Box 10412 Robert F. Sullivan Palo Alto, CA 94303 U. 5. Nuclear Regulatory Commission P. O. Box 1863 Decatur, Alabama 35602 Athens Public Library South and Forrest Athens, Alabama 35611 John A. Raulston Tennessee Valley Authority 400 Comerce Avenue, W10 C127 -
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