ML20195E527
| ML20195E527 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 10/31/1988 |
| From: | Larson C NORTHERN STATES POWER CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| IEB-88-009, IEB-88-9, NUDOCS 8811080174 | |
| Download: ML20195E527 (3) | |
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Northem States Power Company 414 Nicollet Mall Minneapolis, Minnesota $stol 1927 Telephone (612) 330-5500 October 31, 1988 NRC Bulletin 88-09 Director of Nuclear Reactor Regulation U S Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket Nos. 50-282 License Nos. DPR-42 50 306 DPR 60 Response to NRC Bulletin 88-09 Thimble Tube Thinning in Westinghouse Reactors The followin6 information is provided in response to Reporting Re-quirement 3b of NRC Bulletin 88-09, Thimble Tube Th nning in Westing-house Reactors.
Since early 1987 Prairie Island has had an inforr.al program in place that calls for eddy current inspections of all iacore flux thimbles every refueling ou*. age until such time that reliable wear rate data can be established.
Once these rates are established, the need to inspect every refueling would be re evaluated and a new inspection frequency determined.
To date three inspections ha.e been conducted, two on Unit 1 and one on Unit 2, resulting in the c pping of one thim-ble on each unit.
These thimbles had exceeded the interim acceptance criteria of 40 to 50% wall loss.
The inspections and capping of the worn thimbles were performed under the Prairie Island work control process and are documented accordingly.
It is our intention to formalize the thimble tube inspection program and acceptance criteria to document conformance with the requirements of Criterion 1 of NRC Bulletin 88 09.
This will be completed by De-cember 31, 1989 This completion date will allow us to incorporate the results of the Westinghouse Owners Group Bottom Mounted Instrumen-tation Pro 6 ram into our program, lirtil this program is formalized, we will continue with the informal inspection program described above.
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Director of NRR Northem States faer Company October 31, 1988 Page 2 Please contact us if you have any questions related to our response to NRC Bulletin 88-09.
.m C E Larson Vice President Nuclear Generation c: Regional Administrator - Region III, NRC NRR Project Manager, NRC Senior Resident Inspector, NRC C Charnoff Attachment
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l UNITED STATES NUCLEAR REGULATORY COMMISSION NORTHERN STATES POWER COMPANY PRAIRIE ISIAND NUCLEAR GENERATING PIANT DOCKET NOS. 50 282 50 306 INFORMATION REQUIRED BY NRC BULLETIN 88 09 Northern States Power Company, a Minnesota corporation, with this letter is submitting information required by NRC Bulletin 88 09 for the Prairie Island Nuclear Generating Plant.
This letter contains no restricted or other defense information.
NORTHERN STATES POWER COMPANY W
By j
C E Lar(on Vice Prdsidend Nuclear Generation On this 3 / day of[ < /#8h v
,/0 before me a notary public in and for said County, personally appedred C E Larson, Vice President Nuc-lear Generation, 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 l'is knowledge, information, and belief the statements made in it are true and that it is not interposed for delay.
YV n,n,/2' 4 y
EDY L KLAPPERICK NOTARY PUBLIC--MiNNESof4 ANOKA COUNTY Ny Commenen bpres Sept 29,1991
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