ML20202E511

Forwards Application for Amends to Licenses DPR-42 & DPR-60, Increasing Reactor Coolant Sys Boron Concentration to Meet Requirements of Tech Specs

ML20202E511
Person / Time
Site:	Prairie Island
Issue date:	02/10/1998
From:	Sorensen J NORTHERN STATES POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20202E516	List: ML20202E511 ML20202E557 ML20202E569
References
NUDOCS 9802180168
Download: ML20202E511 (3)

Text

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Northern States Power Company

, Prairie Island Nuclear Generating Plant

$?5n%.$e*i5 February 10,1998 10 CFR Part 50 Section 50.90 U S Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 PRAIRIE ISLAND NUCLEAR GENER.ATING PLANT Docket Nos. 50 282 License Nos. DPR 42 50 306 DPR 60 License Amendment Request Dated February 10,1998 One Time Reduction of Mode 6 Reactor Coolant System Boron concentration Attached is a request for a change to the Technical Specifications, Appendix A of the Operating Licenses, for the Prairie Island Nuclear Generating Plant. This request is submitted in accordance with the provisions of 10 CFR Part 50, Section 50.90.

Prairie Island Unit 2 was shut down on January 24,1998 to repair a small leak on a part length control rod drive mechanism (CRDM). When Unit 2 was shutdown, it was believed that the repairs could be performed with the unit in the Cold Shutdown condition, and the reactor coolant system was only borated to the level necessary to support Cold Shutdown (Mode 5) operations, not to a concentration necessary to support Refueling (Mode 6) operation. As described in Exhibit A to this letter, it may be necessary to remove the reactor vessel head to complete the repairs on the part length CRDM. Tho removal of the reactor vessel head would place the unit in Mode 6 and it would be necessary to increase the reactor coolant system boron concentration to meet the requirements of the Technical Specifications.

Increasing the boron concentration uniformly throughout the reactor coolant system requires circulation of the coolant throughout the reactor coolant system. However, when in Mode 5, the reactor coolant pumps are secured and decay heat is removed via the residual heat removal (RHR) system. The RHR system does not provide forced circulation through all portions of the reactor coolant system. Increasing reactor ,

coolant system boron concentration uniformly to the level required for entry into Mode 6, as required by Technical Specifications, would require operation of the reactor I{

coolant pumps. However, because the part length CRDM that was leaking has been T){

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USNRC NORTHERN STATES POWER COMPANY February 10,1998 Page 2 removed from the reactor vessel head, the reactor coolant system is not considered intact and a reactor coolant pump cannot be started.

This License Amendment Request proposes a limited duration change to the Prairie Island Technical Specifications that would allow a reduction in the boron concentration required for Mode G. Tne current requirement of greater than or equal to 2000 ppm would be reduced to greater than or equal to 1900 ppm. Under the proposed change, if it became necessary to remove the reactor vessel head during the current Unit 2 forced outage, the active volume of the reactor coolant system would be maintained at a boron concentration of 21900 ppm to ensure that K.n remains below 0.95 at all times.

Exhibit A contains a description of the proposed change, the reasons for requesting the change, the supporting safety evaluation and significant hazards determination. Exhibit B contains the current Prairie Island Technical Specification page marked up to show the proposed change. Exhibit C contains the revised Technical Specification page.

Note that although the proposed Technical Specification change applies only to Unit 2, and there are no technical changes to the Unit i specifications, the Unit 1 Technical Specifications are administratively affected since Northern States Powsr utilizes only one Technical Specification manual for both units. Therefore, when approved, the proposed changes should be incorporated into both the Unit 1 and Unit 2 Technical Specification pages.

The proposed License Amendment will only be required if it becomes necessary to remove the reactor vessel head to support repairs during the current Unit 2 forced outage.

Since the processing of this License Amendment Request utilizing the provisions of 10 CFR Part 50, Section 50.91(a)(2) would result in a substantial delay in the Prairie Island Unit 2 repairs and the subsequent return to power operation, NSP respectfully requesto handling of this License Amendment Request in accordance with the provisions of 10 CFR Part 50, Section 60.91(a)(5) where the Commission finds that an emergency situation exists, if the proposed License Amendment is not processed in accordance with the provisions of 10 CFR Part 50, Section 50.91(a)(5), completion of the repairs on the Unit 2 reactor coolant system will be delayed, and Unit 2 will be prevented from resumption of plant operation at a cost of approximately $150,000 per day for replacement power.

Because of the circumstances surrounding the repair of the Unit 2 part lerigth CRDM and the unanticipated need to enter Mode 6 for the repairs, NSP was unable to predict that the proposed License Amendment would be required. NSP has used its best efforts in preparing for and implementing the repairs on Prairie Island Unit 2 and has not intentionally created an emergency situation to take advantage of the provisions of 10 CFR Part 50, Section 50.91(a)(5).

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USNRC NORTHERN 8TATES POWER COMPANY F;bruary 10,1998 Page 3 Please contact Gene Eckholt (612 3881121) if you have any questions related to this License Amendment Request.

oel P Sorensen Plant Manager Prairie Island Nuclear Generating Plant c: Regional Administrator Ill, NRC NRR Project Manager, NRC Senior Resident inspector, NRC State of Minnesota Attn: Kris Sanda J E Silberg Attachments:

Affidavit Exhibit A - Evaluation of Proposed Changes to the Technical Specifications.

Exhibit 8 - Proposed Changes Marked Up on Existing Technical Specification Pages.

Exhibit C Revised Technical Specification Pages,