ML20042B760
| ML20042B760 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 03/18/1982 |
| From: | Clark R Office of Nuclear Reactor Regulation |
| To: | William Jones OMAHA PUBLIC POWER DISTRICT |
| References | |
| REF-GTECI-A-49, REF-GTECI-RV, TASK-A-49, TASK-OR NUDOCS 8203260004 | |
| Download: ML20042B760 (4) | |
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- k. ' % 2 4/997[ c'O-ifr. W. C. Jones
- Mpt' Division llanager, Production 0)erations x x Onaia Public Power District Q
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Omaha, fiebraska 68102
Dear Hr. Jones:
During our meeting of thrch 3,1982 with the Conbustion Engineering Group and the three CE flSS Owners, wno received our August 21, 1981 letter con-cerning pressurized thermal shock (PTS), it was requested that we pro-vide a fomal request for any additional information which would be desired regarding the PTS issue. The enclosure identifies the requested additional information. tle request the infomation be submitted by April 30,1982.
The reporting and/or recordkeeping requirements of this letter affect fewer than ten respondents; therefore, 0!B clearance is not required under P. L. 9C-511.
Sincerely.
011gr.m1 Cmn$ t" Robert A. Clark, Chief Operating Reactors Branch #3 Division of Licensing
Enclosure:
Request for Additional Infomation cc w/ enclosure:
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G PDR ADOCK 05000285 d FFTDIAL RECORD COPY usomou-mem P
Omaha Public Power District cc:
Marilyn T. Shaw, Esq.
LeBoeuf, Lamb, Leiby & MacRae 1333 New Hampshire Avenue, N.W.
Washington, D. C.
20036 Mr. Jack Jensen Chainnan, Washington County Board of Supervisors Blair, Nebraska 68023 U.S. Environmental Protection Agency Region VII ATTN: Regional Radiation Representative 324 East lith Street Kansas City, Missouri 64106 Mr. Frank Gibson W. Dale Clark Library 215 South 15th Street Omaha, Nebraska 68102 Alan H. Kirshen, Esq.
Fellman, Ramsey & Kirshen 1166 Woodmen Tower Omaha, Nebraska 68102 Mr. Larry Yandel.1 U.S.N.R.C. Resident Inspector P. O. Box 309 Fort Calhoun, Nebraska 68023 Mr. Charles B. Brinkman Manager - Washington Nuclear Operations C-E Power Systems Combustion Engineering, Inc.
4853 Cordell Avenue, Suite A-1 Bethesda, Maryland 20014 Regional Administrator Nuclear Regulatory Commission, Region IV Office of Executive Director for Operations 611 Ryan Plaza Drive Suite 1000 1
Arlington, Texas 76011 j
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Enclosure REQUEST FOR ADDITIONAL INFORMATION CONCERNING PRESSURIZED THERMAL SHOCK AND REGARDING THE "150 DAY" RESPONSE TO NRC LETTER DATED AUGUST 21, 1981 FOR FT. CALHOUN DOCKET N0. 50- 285 Concerning Operator Actions 1.
In CEN-189, only two cases are considered for a SBLOCA with concurrent lors of feedwater.
In one case, PORVs are opened by the operator at 10 minutes to prevent core uncovery.
In the other case, feedwater is restored to the steam generator in 30 minutes to prevent core uncovery.
For both cases, the report stated that 15-30 minutes would provide ample time to initiate feedwater prior to dryout.
Provide the analysis or basis to justify that 15 to 30 minutes is ample time for correct operator action.
2.
In CEN-189, provide an evaluation of the sensitivity of the transient to the time assumed for operator action (i.e., if the operator opens the PORVs at 15 minutes, or 30 minutes, or rescores feedwater alone at 15 minutes, or 20 minutes, or 45 minutes, what are the resulting pre:,-
sure/ temperature transients?).
3.
The Ft. Calhoun analysis took credit for warm prestressing, but stated that to preserve warm prestressing (in some cases), operator action is necessary to maintain plant parameters within pressure temperature limits.
Provide an evaluation of the probability of operator error for all cases where credit is taken for warm prestressing based on operator action.
4.
In your evaluation, the actions described do not pmvide the operator with clear direction for dealing with conflicting concerns that need to be evaluated when considering the operation of HPI and the charging flow as it relates to vessel integrity and maintaining core cooling, Pmvide an evaluation of the need and effectiveness of procedure modifi-cations to clearly identify the concems in the emergency operating pro-cedures themselves. This should be done in contrast of depending upon upgrading operator training alone.
S.
The Ft. Calhoun steam line break analyses, it is assumed that the operator trips reactor coolant pumps in 30 seconds, and reduces high pressure injection and charging flow to control plant pressure. Pro-vide an evaluation of the sensitivity of the transient to the time assumed for operator action.
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Ft$ Calhoun Concerning Probabilistic Risk Assessment (PRA) of Overcooling Transients 1.
Pmvide existing documentation or references of such documentation related to PRAs which would pmvide insight into the probabilities of overcooling events at your plant.
Concerning Overcooling Transients at Your Plant Review the operating history at your plant and identify all overcooling events as well as those events which could have become overcooling events if not mitigated by plant controls or operator actions. Provide a sunriary of each identified event.
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