ML20057B347

Forwards List of Short Term Action Items & Response to Significant Event Investigation Team Short Term Recommendations,W/Regard to Action Taken in Response to 930831 Steam Leak from Secondary Side of SG a

ML20057B347
Person / Time
Site:	Mcguire
Issue date:	09/13/1993
From:	Mcmeekin T DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9309210223
Download: ML20057B347 (6)

Text

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DUKE POWER September 13,1993 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 28055

Subject:

McGuire Nuclear Station, Unit 2 Docket No: 50-370

Dear Sir:

In our letter of September 7,1993, we described the action we have taken in response to the August 31,1993 steam leak from the secondary side of the "A" steam generator and in response to the Confirmation of Action Letter issued by the NRC Region 11 Regional Administrator on September 1,1993. This letter provides additional details of our actions.

Attachment 1 is a listing of all the short term action items developed from the comprehensive investigation performed by the Site Management Team (SMT).

All these short term items were complete prior to our conference call with the NRC Region 11 Regional Administrator on September 8,1993 requesting concurrence to enter Mode 2.

Attachment 2 is a listing of all the short term (Mode 4) recommendations from the Significant Event Investigation Team (SEIT) and the corrective action we have implemented for each. Our evaluation of all the SEIT recommendations as well as the corrective actions we identified for the short term items were complete prior to our conference call with the NRC Region 11 Regional Administrator on September 8,1993 requesting concurrence to enter Mode 2.

I We will notify you in writing when all the long term action items from both the SEIT and SMT investigations have been completed.

Very truly yours, Yuk t .

T.C. McMeekin 3 9309210223 930913 PDR ADOCK 0500o370 D

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l I McGuire Nuclear Station, Unit 2 Docket No: 50-370 Page 2 xc: Mr. S.D. Ebneter Administrator, Region 11 U.S. Nuclear Regulatory Commission 101 Marietta St., NW, Suite 2900 Atlanta, Ga. 30323 Mr. Victor Nerses U.S. Nuclear Regulatory Commission Office of Nuclee Reactor Regulation Washington, D.C. 20555 Mr. G.F. Maxwell NRC Resident Ins sector McGuire Nuclear 3tation U. S. Nuclear Regulatory Commission

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I Attachment 1 McGUIRE NUCLEAR STATION SMT SIIORT TERM ACTION ITEMS 1

1. Effect repairs to 2CF-130.

2. Reload 4 ice baskets in bay 22.

3. Remove water on the A/D side oflower containment and pipe chase.

4. Pass the information concerning the generic implications of this event to other Duke .,

plants and nuclear industry.

5. Charter a Mechanical Maintenance investigation of this event.

6. Complete disassembly investigation to determine the mechanical failure of 2CF-130.

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7. Change procedure MP/0/A/7600/06, Kerotest Y-Type Valve Corrective Maintenance, to clarify reassembly steps.

8. Place administrative hold on the use of the vendor's on-line leak sealing repair methods that involve removal of pressurized pipe caps on high energy systems.

9. Place procedure MP/0/A/7650/77 on administrative hold.

10. Clarify management oversight responsibilities for on-line leak sealing activities within l Mechanical Maintenance.

I 1. Brief Mechanical Maintenance managers to heighten their awareness regarding training and qualification requirements and management oversight of the activities of vendors, contractors and other interfacing personnel.  !

12. Change post _ maintenance testing on 2CF-130 following repair to include leak checks at three points: 1) system cold with "A" S/G secondary side filled 2) while in mode 4 i and 3) at normal system temperature and pressure. All checks to be done with pipe cap removed.

13. Operations management, as an interim measure,' will issue a memo to all Operations shift and staff personnel requiring that Mechanical Maintenance personnel accompany _

vendor personnel when interfacing with Operations for the purpose of obtaining Operations clearance authorization to perform a leak repair activity. ,

Attachment 1 l

14. Operations will generate a special order dire-cting that shift briefmgs will be modified to conduct NLO briefings outside the control room. The special order will further state that no other administrative meetings will be held in the control room during turnover.

15. Document the basis for the decision to hold two ice condenser lower inlet doors closed during the recovery from this event.

16. Troubleshoot the problem on 2NV-1.

17. Replace 2NV-1 solenoid valve and lead wires including associated conduit. ,

18. Review and make appropriate changes to procedure MP/0/A/7600/06 from a human factor standpoint and for technical accuracy.

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l Attachment 2 McGUIRE NUCLEAR STATION RESPONSE TO SEIT SIIORT TERM RECOMMENDATIONS RECOMMENDATION A: Operability of the ice condenser shall be fully verified including required ice inventory, operation of the lower inlet

, doors, drains are clear and verification that frost buildup will not adversly affect performance of the ice condenser.

RESPONSE: The operability of the ice condenser was verified prior to entry into mode 4 by inspections, analysis and performance of necessary tech, spec. surveillances.

RECOMMENDATION B: An evaluation of all equipment in containment exposed to elevated temperature, humidity and water shall be completed to assure capablity to perform function is not adversely impacted. This shall include considerations of environmental qualifications of effected components .

RESPONSE: Since equipment in upper containment was not exposed to the effects of the steam leak, we limited our evaluation to equipment in lower containment. We completed the evaluation and required inspection of lower containment equipment prior to entry into mode 4.

RECOMMENDATION C: Evaluate the consequences of improper maintenance on other Kerotest packless valve applications and take _ ,

appropriate corrective actions.

RESPONSE: Rather than evaluate the consequences of improper maintenance, we reviewed all work orders performed on packless Kerotest valves during 2EOC-8 and found that 31 had work performed that required disassembly of the valve. We then either verified that each of these valves had received a documented full stroke post maintenance or we performed a full stroke. No additional problems were found. We determined that there is a high confidence level that no related problems exist on Unit 1 and therefore took no additional action for Unit 1. This confidence is based on the results from the Unit 2 review and the fact that potential problems on Unit 1 should have been eliminated by post maintenance testing during 1EOC-8 or by challenges to the valves during subsequent startup, power operation and shutdown. All these action were completed prior to mode 4. ,

RECOMMENDATION D: Immediately suspend on-line pipe cap removals on pressurized high energy systems until enhancements _ are made in the ,

process for verifying amount of leakage through isolation valves. .

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Attachment 2 RESPONSE: We have taken the following actions in response to this recommendation: 1) Operations issued Special Order 93-13, Pipe Cap Removal on 9/4/93 which says "Immediately suspend on-line pipe cap removals on high energy water and steam systems pressurized to greater than or equal to 600 PSI until further notice." 2) On 9/6/93, Maintenance placed procedures which involve the removal of pressurized pipe caps on high energy systems on administrative hold until further evaluation. 3) On 9/6/93, Chemistry issued USAC # P-134 which says "immediately suspend on-line pipe cap removals on high energy water and steam systems pressurized to greater than or equal to 600 PSI until further notice" .

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