ML20086T901
| ML20086T901 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 12/31/1991 |
| From: | Parker T NORTHERN STATES POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-89-002, IEB-89-2, NUDOCS 9201070103 | |
| Download: ML20086T901 (3) | |
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Northom States Power Company 414 Nicollet Mall Minneaoolis, Minnesota 55401 1027 Telephone (012) 330-5500 December 31, 1991 NRC Bulletin 89 02 U S Nuclear Regulatory Commission Attn:
Document Control Desk Washington, DC 20555 PRAIRIE ISLAND NUCLEAR CENERATING PIANT Docket Nos. 50-282 License Non. DPR 42 50 306 DPR 60 Updated Request for Relief From the Schedule Requirement s of NRC Bu11etin19-02
Reference:
Letter from Thomas M Parker (NSP) to Director of Nuclear Reactor Regulation (NRC), " Updated Request for Relief from the Schedule Requirements of NRC Bulletin 89-02", dated May 30, 1991.
The purpose of this letter is to request further relief from the schedular requirements of Bulletin 89-02, " Stress Corrosion Cracking of High llardness Type 410 Stainless Steel Internal Preloaded Bolting in Anchor Darling Valves",
for the inspection of the Unit 1 and Unit 2 Residual lleat Removal Pump discharge check valves.
In the referenced letter we committed to complete replacement of the retaining block studs in the Residual lleat Removal (RHR)
Pump discharge check valves on both units (two valves per unit) prior to December 31, 1991, provided there were no further procurement related delays.
The Residual Heat Removal Pump discharge valves are Crane 8" swing check valves similar in design and material to the Anchor Darling check valves specifically addressed by NRC Bulletin 89-02.
In response to the inspection requirements of NRC Bulletin 89-02, we have elected to replace all retaining block studs in the affected swing check valves with bolts of an improved material and to inspect the removed bolts.
A summary of the check valve inspections performed, to date, in response to
-NRC Bulletin 89-02 is providen by the following table:
Total Number Vt.1ve s Affected Check Valves Application of Valvrs
,,lrspected Anchor Darling 12" Accumulator Discharge 8 (4/ unit) 8 Crane - 8" RHR Pump Discharge 4 (2/ unit) 3 Crane 8"
RHR Pump Suction 4 (2/ unit) 0 030051 Y
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Director NRR December 31, 1991 Nodhorn States Power Company Page 2 Inspection of the bolts removed from the eight Anchor Darling valves, which were performed by maintenance and engineering personnel, found the bolts to be intact. These bolts were not inspected by a certified inspector due to AIARA concerns.
Bolts which were removed from the three residual heat removal pump discharge check valves showed no signs of degradation during visual inspection by a certified inspector, During the replacement of the bolts on the third residual heat removal pump discharge valve (Unit 2 valve), several bushinge were found to be missing. A subsequent evaluation concluded that operation of the valve without these bushings did not present any operational or safety concerns.
Ilowever, only one set of rep 1r ement bushings was available on-site, which were installed in the third valve. There is some probability that these bushings may also be missing from the other Unit 2 valve, yet to be inspected.
Because of that possibility, and because no replacement bushing are available, inspection of the remaining Unit 2 valve was deferred.
Due to ALARA considerations and no degradation ot the bolts inspected to date, we feel it is prudent to delay the inspection of the remaining Unit 2 residual heat removal pump discharge valve until replacement bushings are available.
We are experiencing difficulty in obtaining replacement bushings from the valve supplier because of problems they have encountered with their source for the bushing material.
The valve supplier cannot provide an expected delivery date for the replacement bushings, Because of this uncertainty with the availability of replacement parts, it is difficult to predict when the inspection of the remaining Unit 2 valve will be complete.
We will pursue procurement of the necessery parts with the manuiacturer and will complete the inspection of the remaining Unit 2 valve when the parts are received, We expect that this remaining inspection of the Unit 2 residual heat removal pump discharge check valve will be completed before the inspection of the Unit 1 residual heat removal suction valves which is scheduled to be completed during the Spring 1994 refueling outage.
These further delays in completion of our response to Bulletin 89-02 were discussed with the NRC Project Manager for Prairie Island on December 17, i
- 1991, Please contact us if you have any questions related to our response to l
NRC Bu11etinf89 02.
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s Yk6 Thomas M Parker Manager Nuclear Support Services c: Regional Administrator - Region III, NRC Senior Resident Inspector, NRC NRR_ Project Manager, NRC J E Silberg l
Attachment:
Affidavit of Thomas M Parker l
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UNITED STATES NUCLEAR REGULATORY COMMISSION NORTHERN STATES POWER COMPANY PRAIRIE ISLAND NUCLEAR GENERATING PLANT DOCKET NO. 50 282 50 306 SUPPLEMENTAL RESPONSE TO NRC BULLETIN 89 02 Northern States Power Company, a Minnesota corporation, with this letter is submitting supplemental information in response to NRC Bulletin 89 02, This letter contains no restricted or other defense information.
NORTHERN STAT ' P VER MPANY By
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' Thomas el Parker Manager Nuclear Support Services
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i /f7/before me a notary public in and for On this dsy of JMA said County, personally appeared Thomas M Parker, Manager, Nuclear Support Services, and-being first duly sworn acknowledged that he is authorized to execute this document on behalf _ of Northern States Power Company, that he knows the contents thereof, and that to the best of his knowledge, information, and belief the statements made in it are true and that it is not interposed for delay.
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