ML20079G046

Application for Amend to License DPR-42 & DPR-60,providing Assurance of Reactor Coolant Vent Sys Operability & Reliability,Implementing Requirements of NUREG-0737,Item II.B.1

ML20079G046
Person / Time
Site:	Prairie Island
Issue date:	01/13/1984
From:	Musolf D NORTHERN STATES POWER CO.
To:
Shared Package
ML20079G042	List: ML20079G038 ML20079G046 ML20079G054
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-2.B.1, TASK-TM TAC-53458, TAC-53459, NUDOCS 8401190392
Download: ML20079G046 (6)

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UNITED STATES NUCLEAR REGULATORY COMMISSION NORTHERN STATES POWER COMPANY PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket No. 50-282 50-306 REQUEST FOR AMENDMENT TO OPERATING LICENSE NOS. DPR-42 & DPR-60 (License Amendment Request Dated January 13, 1984)

Northern States Power Company, a Minnesota corporation, requests authorization for changes to the Technical Specifications as shown on the attachments labeled Exhibit A and Exhibit B. Exhibit A describes the proposed changes along with reasons for the change. Exhibit B is a set of Technical Specification pages incorporating the proposed changes.

This letter contains no restricted or other defense information.

NORTHERN STATES POWER COMPANY By w David Musolf Manager - Nuclear Support Services On this /3f/ day of (J,3,,ff,,n m , /e?#// before me a notary public in and for said County, personallg appeared (havid Musolf, 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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EXHIBIT A Prairie Island Nuclear Generating Plant License Amendment Request - Dated January 13. 1984 Proposed Changes to the . Technical Specifications Appendix A of Operating Licenses-DPR-42 and 60 Pursuant to 10 CFR 50.59 and 50.90, the holders of Operating Licenses DPR-42 and 63 hereby propose the following changes to Appendix A, Technical Specifications:

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Specification: Reactor Coolant Vent System - TS 3.1/4.18 Proposed Changes See attached Exhibit B Reason for Change This change implements the requirements of NUREG-0737, Item 11.8.1 and is in response to NRC Generic Letter No. 83-37 dated November 1,1983.

-Significant Hazards Evaluation The proposed Technical Specification changes provide assurance of reactor coolant vent system operability and reliability and constitute additional limitations, restrictions and controls not presently included in the Tech-nical Specifications. -

The Prairie Island reactor coolant vent system was installed in response to NUREG-0737, Item II.B.1 and consists of vent paths from the reactor i vessel head and the pressurizer. Each path contains two independently emergency powered, energize to open, valves in parallel which connect to a common header that discharges either to the containment atmosphere or the pressurizer relief tank-(see-Figura 1 or Exhibit A). The lines to the containment atmosphere and pressurizer relief tank each contain an independently emergency powered, energize to open, iscla'. ion valve. The redundancyfin the system design provides protection from the failure of a single vent valve rendering an entire vent path inoperable. The proposed

Technical Specification changes are designed to complement this redundancy and provide additional assurance that the reactor coolant vent system will be available to exhaust noncondensible gases from the reattor cociant system should it-be necessary.

I The proposed Technical Specification Limiting Cenditions for Operation are based on the following premises:

a. Plant action is required if the vent system is in a condition where the failure of a single vent system solenoid operated valve could render

' the vent system completely inoperable.

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b. Plant action is required if either the reactor vessel head vent path or the pressurizer vent path is inoperable.

c. Immediate plant action is required if no reactor coolant vent path is operable.

d. In the event of inoperable vent system valves, power should remain available to all remaining operable valves so that valve position indication and the operator's ability to control the vent system can be maintained. Operator training and normal administrative controls minimize the' possibility of an inadvertent actuation of the vent system and the following design features provide assurance that any loss of reactor coolant resulting from an inadvertent actuation of the vent system will be readily identifiable and controllable:

1) A flow restriction orifice in each vent path limits the vent system flow to less than the flow of the reactor coolant makeup

-system.

, 2) Pressure indication is provided to the control room (see Figure 1) to enable the opeeator to recognize any discharge of reactor coolant through the vent system.

The actions required by various vent system conditions are summarized in Figure 1 of Exhibit A. The proposed Limiting Conditions for Operation and required actions, in combination with the redundancy in the system design.

provide adequate assurance that the espability to exhaust noncondensible gases from the reactor coolant system will exist should it become necessary.

The proposed reactor coolant vent system Technical Specification Surveil-lance Requirements are based on the following premises:

a. Blocking and tagging all manual valves in ~ the reactor coolant vent system in the open position will eliminate the possibility that a vent path can be blocked by the inadvertent closure lof any of the vent system manual valves.

b. Cycling of each solenoid operated vent valve once each refueling ensures the ability of these valves to open if required to vent the reactor coolant system. More frequent cycling of the valves is not practical because they cannot be isolated from the reactor coolant system while the plant is operating.

c. . Flow testing assures that there are no blockages in the reactor coolant vent system piping that would prevent venting of noncondensible gases from the reactor coolant system. Flow testing need only be performed every five years because of the difficulty involved in performing a flow test of the entire vent system, the low probability of a blockage occurring in the vent system piping and because the reactor vessel head vent path is used to vent the reactor vessel head to the containment during the normal reactor coolant system fill and vent procedure.

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The proposed Technical Specification surveillance requirements provide adequate assurance that the reactor coolant vent system is operable and able to perform its intended function.

Based on the above discussion, operation of the plant in accordance with the proposed Technical Specification changes will not:

(1) involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) create the possibility of a new or different kind of accident from any

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accident previously evaluated; or (3) involve a significant reduction in a margin of safety.

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EXHIBIT A Figure 1 Reactor L,0, Pressurizer Vessel  ;><3--il ; ,; ,, Relief i

Head Tank i

w, L.O. , m Containment Pressurizer :X)-4,3 ,, -' '

Atmosphere v,

Reactor Coolant Vent System Inoperable Valves A- B C D E F Required Action X None X None X X Return .1 and/or B to operable within 30 days X None X None X X Return C and/or D to operable within 30 days X X X X Return A, B, C or D to operable within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> X Return E to operable within 30 days X Return F to operable within 30 days X X P.eturn E and/or F to operable within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> A-4 L .. _ _ _ _ _ _ _ ___ _ ___-______ - - ____ _ a

EKRIBIT B Prairie Island Nuclear Generating Plant License Amendment Request - Dated January 13, 1984 Proposed changes to the Technical Specifications Appendix A of Operating Licenses DPR-42 and 60.

Exhibit B consists of revised pages of Appendix A Technical Specifications as listed below:

Pages TS-i TS.3.1-2A (new page)

TS.3.1-3A TS.4.18-1 (new page)

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