ML20247A598
| ML20247A598 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 06/05/1989 |
| From: | Larson C NORTHERN STATES POWER CO. |
| To: | Wright G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 8907210270 | |
| Download: ML20247A598 (3) | |
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Northem States Power Company 4
414 Nicollet Md Minneapolis, Minnesoto 554011927 Telopme (612) 330 5500
~ June 5-1989 3
Mr G C Wright, Chief Operations Branch, Region III U S Nuclear Regulatory Commission 799 Roosevelt Road-Glen Ellyn, Illinois 60137 PRAIRIE ISIAND NUCLEAR GENERATING PLANT Docket Nos. 50-282 License Nos. DPR-42 50-306 DPR-60 Response to Notice of Violation Inspection Reports No. 50-282/89014(DRS) and 50-306/89015(DRS)
In response to your letter of May 4, 1989, which transmitted Inspection Reports No. 282/89014 and 306/89015, the following information is offered.
Violation 10 CFR Part 50, Appendix J Paragraph III.A.3.(a) states, in part, that all Type A tests shall be conducted in accordance with the provisions of the American Natio*1a1 Standard N45.4-1972, Leakage Rate Testing of Containment Structures for Nuclear Reactors, March 16, 1972. ANSI N45.4-1972, Paragraph 4.2 states, in part, that for retesting, an initial record proof test shall be conducted at time perieds and pressures established by the responsible organization, before any preparatory repairs are made.
Contrary to the above, the licensee shut down Unit 1 for refueling in August 1988, added a ring of packing to each of the four maintenance airlock shaft seals on September 15, 1988, and subsequently performed the local leak rate test and the containment Type A test.
No tests were performed after the unit shutdown in August 1988 and before the repairs done in September 1988 in order to determine the amount of leakage rate improvement prior to the Type A test.
This is a Severity Level IV violation (Supplement I).
Agsnonse to the Vlo1ation j
Corrective Actions Taken and Results Achieved Procedures governing local leakage rate tescing have been changed to require l
I retention of as-found and as-lef t test data for the airlocks.
l 8907210270 990605 PDR ADOCK 05000282 JW 8 1989 o
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a G,C Wright' Jun2 5, 1989
'E Northem States Power Company Corrective Actions to be Taken to Avoid Further Violations Procedures governing volumetric leakage rate testing of containment airlocks will be modified to include additional guidance on performing as-found and j
as-left tests each refueling outage. These tests will be performed even 4.f
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repairs are not scheduled to be done. This will ensure any unexpected i
maintenance, which could arise during an outage, would have the proper initial testing complete, i
Date When Full Como11ance will be Achieved i
All procedure revisions will be in place prior to the next refueling outages, j
presently scheduled for January 1990 for Unit 1 and September 1990 for Unit 2.
'!?emonse to Opyn Item A= part of his review of the Local Leak Rate Testing Program, the inspector reviewed the test procedures and practices and the local leak rate tester (LLRT) used to pressurize penetrations and measure their leak rate.
The penetration test pressure is monitored at the LLRT which is connected to the penetrations by 3/8" poly tubing of up to 100 ft in length. The inspector be maintained at the penetration under high penetration leak rate conditions. He was concerned that at high penetration leak rates, the pressure drop in long lengths of the tygon tube would reduce the actual pressure at the penetration below the pressure being read at the LLRT.
A review of the Type B and C test results showed the largest leakage measurement being 3900 seem for which the pressure drop would be less than 1 psi.
Since significant leakage could be expected to occur during future local leak rate tests, the inspector requested that the applicable test procedures and practices be modified to ensure the required pressure is maintained at the penetration. This was identified as Open Items 282/89014-02 and 306/89015-01
- pending review by the inspector of our corrective action.
Corrective actions are being studied but are not finalized. Potential corrective actions under consideration include:
- placing a pressure gauge immediately at the penetration, or testing to determine pressure drop penalties (which would be added to the supply air pressure) for various leakages and tubing lengths and revise appropriate procedures to apply the penalties.
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r G,Q Wright t
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June 5, _-.1989 R
Page 3-Northem States Power Company Corrective actions will-be in place prior to the next refueling outages, presently. scheduled for January 1990 for Unit 1 and September 1990 for Unit 2.
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Please contact us if you have any questions related to our response to the subject inspection reports.
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C E Larso '
Vice President Nuclear Generation c: Regional Administrator III, NRC Senior Resident' Inspector, NRC NRR Project Manager, NRC C Charnoff i
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