ML19345A914
| ML19345A914 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 11/20/1980 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| FOIA-81-204 NUDOCS 8011250406 | |
| Download: ML19345A914 (4) | |
Text
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M,,, e, v g* wg2ss[tM TENNESSEE VALLEY AUTHORITY 1 v
CHATTANOOGA, TEN?iE'SSEE 37401 l g g 24 pg 3 0'J.
400 Chestnut Street Tower II:
November 20, 1980 t
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Mr.N$NkNR.Denton, Director Office of Nuclear Ractor Regulation 4
l U.S. Nuclear Regulatory Commission l
Washington, DC 20555
Dear Mr. Denton:
4 In the Matter of the
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Docket Nos. 50-259 i
Tennessee Valley Authority
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50-260 50-296 1
4 In response to D. G. Eisenhut's July 16, 1980, letter to H. G. Parris, TVA submitted information for the fire protection system replication and test effort for Browns Ferry on October 1 and October 15, 1980.
In the October 15, 1980, submittal, we stated our understanding of the test program and the agreements reached in the July 30, 1980, meeting.
1 Enclosed are additional comments a the proposed test plan that was
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. attached to the October 20, 1980, NRC memorandum from Ronald Feit, Chairman, Fire Protection Review Group. Because of the potential for najor impacts regarding this matter, we would like to schedule a meeting with the appropriate individuals from NBC-Nuclear Reactor Regulation, and NRC-Office of Nuclear Regulatory Research for resolution of our comments / issues with the proposed test plan. As discussed with members of your staff and with members of the Office of Research Staff, a tentative date of December 2, 1980, was agreed upon.
Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills,) Manager Nuclear Regulation and Safety Subscribo n sworn to efore me this ay of n 1980.
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ADDITIONAL COMMENTS ON THE DRAFT TEST PLAN FOR REPLICATION TESTS FOR FIRE PROTECTION SYSTEPS TVA has a concern that the draft test plan has not been prepared consistent with the objectives of the program stated in the July 16, 1980, letter from D. G. Eisenhut to TVA and the July 15,-1980, letter to the NBC Commissioners from Robert J. Budnitz, Director, Office of Nuclear Regulatory Research. Portions of the test plan appear to be directed to the accumulation of experimental data for development of an " enveloping analysis," rather than the testing of " actual plant configurations and fire protection systems." Our specific comments are provided in the following paragraphs.
Comment No. 1 FIRE BRIGADE RESPONSE TIME For NRC not to accept the fire brigade response time is inconsistent with the program's stated objective, "to prove adequacy of existing plant configuration and fire. protection systems.
The fire brigade drill was conducted at the NRC's request with the resident inspector present to oversee the drill. The resident NRC inspector verified, in a July 30 meeting, that the rapid response time was valid and representative of the brigade's response to elevation 593 of the reactor building. TVA does not see any justification for altering the brigade's actual response time. To do so would invalidate the test results with regard to actual operating conditions at' Browns Ferry.
AMOUNT OF FUEL USED FOR TEST FIRE Comment No. 2 We concur with Sandia Laboratories' position that two gallons of
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flammable liquid would be a quantity that is consistent with the test's objective.
C0ATING OF CABLES IN CABLE TRAYS Comment do. 3 TVA disagrees with the inclusion of uncoated cables into the test program. The design concept behind Browns Ferry is that cable coatings will be used to reduce the base of. ignition and rate of flame spread of the cable.
If the test is to be representative of the Browns Ferry design and the regulatory process at the time the Browns Ferry design was approved, all cables should receive the coating as applied by Browns Ferry standard procedures.
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O Comment No. 4 TEST FAILURE CRITERION The proposed test failure criterion deserves a close review by all concerned parties. As TVA interprets the current feilure criterion any cable failure in a redundant cable tray will be termed a test failure.
It shall then be concluded that the fire protection system at Browns Ferry is not adequate as designed and installed. This is simply not a realistic failure criterion nor are the resulting conclusions valid.
The basic and fundamental question to be answered by the test is whether a single fire could preclude the safe shutdown of Browns Ferry. Has the regulatory process provided the defense in depth to prevent such a situation from occurring? The fire replication test must not test for any cable failure but rather for a common mode cable failure that would remove from service sufficient equipment to preclude a safe shutdown.
It is distinctly possible at Browns Ferry as well as other facilities to sustain damage to both train A and train B cable systema without the loss of safe shutdown capabilities.
TVA believes that if this test is to be presented as a test of the ability of Browns Ferry to withstand fire that, (1) the test criterion be representative of a common mode failure that would preclude safe shutdown, and (2) that this common r. ode failure occur in the tests conducted with and without the suppression system being activated.
Some ambiguities exist in the review group meeting report and the test plan outline in regard to the exact test sequence to be used. We understand that the program will consist of three individual tests.
Test 1 would be used as a screening test and would utilize only the vertical cable trays and conduits. This test would be conducted without fixed suppression systems but with a simulated fire brigade response with manual suppression.
If cable / system integrity is maintained during Test 1, the entire test program will have passed and the program would be concluded for Browr.3 Ferry.
Test 2 will be conducted only if there is a failure during Test 1.
Test 2 will be a full-scale test conducted without fixed suppression in a manner similar to Test 1.
If cable / system integrity is maintained by the simulated fire brigade response with manual suppression, then the total test program should be considered a success and the test program completed.
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l Test 3 will'be conducted only if there is a failure during Test 2.
. Test 3 will be a full-scale test conducted with fixed suppression and a simulated fire brigade response with manual suppression. If cable / system integrity is maintained during this test, the total test program should be considered a success and the test program completed.
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Therefore, a failure of all three tests would be 'necessary to achieve a total test' program failure.
In other words, if cable / system integrity can be maintained during any of the three tests, the e, program should be considered a success.
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SUMMARY
We believe that a clear and. concise test plan should be developed consistent with the stated objective of the test program. Each segment of the test program should be carefully reviewed to ensure that (1) it is consistent with the stated objective, (2) that no deviations are proposed for experimental reasons, and-(3) that the suppositions made be consistent with realistic plant operating conditions.
The impact of a test failure would be dramatic to both TVA and the industry. The program 3
must be carefully structured to ensure that a test failure is truly representative of a system failure that would place the safety of the plant and the general public in serious jeopardy. To have a test program structured in a less precise manner could lead to an ambiguous situation i
if the test failed because, the plant's systems could still provide an adequate margin for public safety. Such test results would be difficult to explain to a skeptical public not familiar with the detail of the test program.
However, if NRC decides to continue this effort then the program should not be labeled as a test of fire protection system for Browns Ferry, but rather as generic tests for experimental data.
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