ML20027E457
| ML20027E457 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 09/28/1982 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| Shared Package | |
| ML20027E456 | List: |
| References | |
| NUDOCS 8211150344 | |
| Download: ML20027E457 (4) | |
Text
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TIENNRS$iEE!VAlt EY AUTHORITY Ahr3A,Ihhb4NESSEE 374ol bha S
400 Chestnut Street Tower II 82 OcI I P\\: 59 I
September 28, 1982 U.S. Nuclear Regulatory Commission Region II ATTN: James P. O'Reilly, Regional Administrator 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303
Dear Mr. O'Reilly:
Enclosed is our response to R. C. Lewis' August 30, 1982 letter to H. G. Parris transmitting Inspection Report Nos. 50-259/82-23,
-260/82-23, -296/82-23 regarding activities at our Browns Ferry Nuclear Plant which appeared to have been in violation of NRC regulations. We have enclosed our response to Appendix A, Notice of Violation. If you have any questions, please call Jim Domer at FTS 858-2725.
To the best of my knowledge, I declare the statements contained herein are complete and true.
Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, Manager i
Nuclear Licensing Enclosure 8211150344 821021 PDR ADOCK 05000259 G
PDR An Equal Opportunity Employer
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RESPONSE - NRC INSPECTION REPORT NOS.
50-259/82-23, 50-260/82-23, AND 50-296/82-23 R. C. LEWIS' LETTER TO H. G. PARRIS DATED AUGUST 30, lo82 Appendix A Iten - (25o, 260, 296/82-29-09) 10CFR50, Appendix B, cri.terion V, as implemented by TVA's OA Tooical Report, TVA-TR-75-1, requires activities affecting quality be prescribed by procedures appropriate to the circumstance and accomplished in accordance with those procedures.
Contrary to the above, the reouirement for procedures appropriate to the circumstances was not met prior to Julv 30, 1982, in that Surveillance Instruction 4.7.C, Secondary Containment, did not account for inleakage to the secondary containment zone under test that results from operation of the normal reactor building ventilation system in adjacent secondary containment zones. This condition allowed masking of the true inleakage to the secondary containment zone under test.
This is a licensee identified violation.
This is a Severity Level IV Violation (Supplement I).
1.
Admission or Denial of the Allered Violation TVA admits the violation occurred as stated.
2.
Reasons for the Violation if Admitted The design of the 3-unit facility at Browns Ferry provides for the isolation of the entire reactor building or each of the four individual zones which comprise the building. There is a reactor zone for each unit and a common refueling zone. The instruction, written to show compliance with Technical Specification h.7.C., showed versatility to allow testing of the building or selected zones. Tests performed at the beginning of a refueling outage were conducted on the refueling zone and the outaFe unit's reactor zone. This was the preferred test method to lessen the potential for an inadvertent shutdown of the operating units. Performance of any secondary containment test
F
- requires initiation of the standby gas treatment systen. This causes isolation of the normal ventilation system for the zones being tested.
For an operating unit, this loss of ventilation causes main steam tunnel temperatures to increase toward the isolation setpoint. This isolation in turn causes a reactor scram.
1 Zone testing an outage unit does not affect the ventilation systen operation on the operating units. Because the normal ventilation system maintains a negative pressure on its associated zone, this negative pressure can affect the results of a secondary containment test on an adjacent zone. The potential effect dapends on the integrity of the zone interfaces. Personnel associated with the secondary containment testing did not realize the potential nonconservative effect of adjacent ventilation system operation and consequently did not provide for control of this variable or allowance for its effect.
During the nerformance of the procedure in July and August 1982, the difficulties initially encountered were thought to be associated with flow measuring techniques and instruments. Continued investigation using the zone versatility contained in the procedure revealed one large and several small breaches in secondary containment integrity as well as interzone leakage paths. It was during this series of intensive tests that the potential effect of associated ventilation system operation was first indicated. We wish to point out that, even though a variable which could affect the test results in a nonconservative direction was not controlled, the test conducted in July and August did adequately identify the breach of secondary containment that existed.
3 Corrective Steos Which Will Be Taken and the Results Achieved Once the potential effect of the normal ventilation system was recognized, the test nrocedure was revised accordingly. Now, if zone testing is selected to prove secondary containment integrity, associated zone ventilation system effects are evaluated. All leakage pathways identified during tests perforned in July and August were repaired. The revised procedure was performed August 8 and 9 and secondary containment integrity was proven to be well within technical specification limits.
4 Corrective Steos Which Will Be Taken To Avoid Further Violations i
No further actions are required.
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4 5.
Date When Full Cornliance Will Be Achieved Full compliance was achieved on August 0, 1082 with the successful perforrlance of the revised test procedure.
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