ML17332A763

Application for Amends to Licenses DPR-58 & DPR-74,revising TS Section 3.7.1.1,Table 3.7-1 & Bases Re Turbine Cycle Safety Valves

ML17332A763
Person / Time
Site:	Cook
Issue date:	05/19/1995
From:	Fitzpatrick E INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML17332A764	List: ML17332A763 ML17332A765
References
AEP:NRC:1213, NUDOCS 9505240165
Download: ML17332A763 (11)

Text

RIDRIWY CELERATED RIDS PROCESSING) 1 REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9505240165 DOC.DATE: 95/05/19 NOTARIZED: YES DOCKET FACIL:50-315 Donald C. Cook Nuclear Power Plant, Unit 1, Indiana M 05000315 50-316 Donald C. Cook Nuclear Power Plant, Unit 2, Indiana M 05000316 AUTH. NAME AUTHOR AFFILIATION FITZPATRICK,E. Indiana Michigan'ower Co. (formerly Indiana & Michigan Ele P RECIP.NAME RECIPIENT'AFFILIATION Document Control Branch (Document Control Desk) R

SUBJECT:

Application for amends to licenses DPR-58 & DPR-74,revising TS section 3.7.1.1,Table 3.7-1 & bases re turbine cycle safety valves.

DISTRIBUTION CODE: AOOID TITLE: OR COPIES RECEIVED:LTR Submittal: General Distribution J ENCL / SIZE:

NOTES:

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Y'OTE TO ALL RIDS" RECIPIEYTS:

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TOTAL NUMBER OF COPIES REQUIRED: LTTR '2 ENCL 11

Indiana Michigan Power Company P.O. Box 16631 Columbus, OH 43216 FI May 19, 1995 AEP:NRC'1213 Docket Nos.: 50-315 50-316 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555 Gentlemen:

Donald C. Cook Nuclear Plant Units 1 and 2

.TECHNICAL SPECIFICATION CHANGE REQUEST, SECTION 3.7,1.1, TABLE 3.7-1, AND THE BASES FOR SECTION 3.7.1.1 (TURBINE CYCLE - SAFETY VALVES)

This letter and its attachments constitute an application for amendment to the technical specifications (T/Ss) for the Donald C. Cook Nuclear Plant Units 1 and 2. Specifically, we are proposing to modify T/S 3.7.1.1, Table 3.7-1, and the associated bases description. The changes modify the power range neutron flux high setpoint in response to an issue raised in Westinghouse Nuclear Safety Advisory Letter (NSAL)94-001, and provide clarification of the existing action statements in T/S Section 3.7.1.1.

Attachment 1 provides a detailed description of the proposed changes, the justification for the changes, and our determination of no significant hazards consideration performed pursuant to 10 CFR 50.92. Attachment 2 contains the existing T/S pages marked to reflect the proposed changes. Attachment 3 contains the proposed T/S pages. Attachment 4 contains a copy of the Westinghouse NSAL 94-001.

We believe the proposed changes will not result in (1) a significant change in the types of any effluent that may be released offsite, or (2) a significant increase in individual or cumulative occupational radiation exposure.

These proposed changes have been reviewed by the Plant Nuclear Safety Review Committee and the Nuclear Safety and Design Review Committee.

9505240165,.950519 PDR P

'DR ADQCK 05000315

f U. S. Nuclear Regulatory Commission AEP:NRC:1213 Page 2 In compliance with the requirements of 10 CFR 50.91(b)(1), copies of this letter and its attachments have been transmitted to the Michigan Public Service Commission and to the Michigan Department of Public Health.

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E. E. Fitzpatrick Vice President SWORN TO AND SUBSCRIBED BEFORE ME THIS ~~ DAY OF 1995 Notary Public eh Attachments CC: A. A. Blind G. Charnoff J. B. Martin NFEM Section Chief NRC Resident Inspector - Bridgman J. R. Padgett

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ATTACHMENT 1 TO AEP'NRC'1213 DESCRIPTION AND JUSTIFICATION OF CHANGES 10 CFR 50.92 ANALYSIS FOR CHANGES TO THE DONALD C. COOK NUCLEAR PLANT UNITS 1 AND 2 TECHNICAL SPECIFICATIONS to AEP:NRC:1213 Page 1 DESCRIPTION OF CHANGES The proposed amendment to technical specification (T/S) 3.7.1.1 makes the following specific changes to the Cook Nuclear Plant units 1 and 2 T/Ss:

Table 3.7-1 is to be modified to reflect the corrected values for the neutron flux high setpoints (setpoints) to be used in the event that one or more main steam safety valves (MSSVs) are determined to be inoperable, as provided in Westinghouse Nuclear Safety Advisory Letter (NSAL)94-001. A copy of this letter is provided as Attachment 4.

2. The bases for Section 3.7.1.1 are to be modified to reflect the corrected methodology for developing the setpoints.

3. The ACTION statement of the T/S is to be revised to clarify what actions are required in MODES 1, 2, and 3 when main steam safety valves are declared inoperable. Specifically, ACTION

a. will apply only to MODES 1 and 2 and will refer the reader to ACTION b. when the requirements for continued operation in MODES 1 and 2 cannot be met. ACTION statement b. is modified to allow 3 or 4 loop operation in MODE 3. It also clarifies that the unit should be in HOT SHUTDOWN (instead of COLD SHUTDOWN) when the other required actions are not accomplished.

REASONS FOR CHANGES AND JUSTIFICATION FOR CHANGES CHANGES TO TABLE 3.7-1 AND BASES FOR 3.7.1.1 We were notified by Westinghouse in Nuclear Safety Advisory Letter (NSAL)94-001 that the present methodology for calculating the setpoints when one or more MSSVs are inoperable is not conservative.

The present methodology includes an assumption that the maximum allowable initial power level is calculated based on a linear function of the available MSSV relief capacity. Under certain conditions, and with typical safety analysis assumptions, a loss of load/turbine trip transient at part-power conditions may result in overpressurization of the main steam system when operating in accordance with the setpoints calculated by this methodology.

The revised methodology presented by Westinghouse in the NSAL was used to determine conservative setpoints. This guidance provides a method to calculate the maximum power level that will provide sufficient heat removal capability during operation with the given number of inoperable MSSVs. These new setpoints, along with the revised methodology, are to replace the existing text in Table 3.7-1 and the bases for Section 3.7.1.1 in the Cook Nuclear Plant T/Ss.

to AEP:NRC:1213 Page 2 CHANGES TO ACTION STATEMENT As presently written, the ACTION statements of T/S 3.7.1.1 require that the power range neutron flux high setpoint be reduced (to account for decreased heat removal capability) when one or more of the MSSVs is declared inoperable in MODES 1, 2, and 3. The neutron flux high setpoint is not a proper constraint for MODE 3 operation, since no operation at power can take place during this MODE.

Therefore, ACTION a. has been rewritten to provide requirements for operation only in MODES 1 and 2 with four reactor coolant loops.

As currently written, ACTION b. permits continued operation with inoperable MSSV's provided the reactor trip breakers are opened; however, the wording is such that this provision is specifically provided only for the case of three reactor coolant loops in operation. The purpose of the MSSVs is to remove energy such that an overpressurization of the secondary side does not occur. With the breakers open, the principal concern is the removal of decay heat. Because energy removal capability is enhanced with additional reactor coolant loops in operation, the T/Ss as presently written are overly restrictive. We are proposing to modify ACTION b. to allow operation with inoperable MSSVs in MODE 3 with a minimum of three reactor coolant loops in operation. This change corrects an oversight in the present version of the T/Ss.

Both ACTION a. and ACTION b. presently require the applicable unit to be in COLD SHUTDOWN (MODE 5) if the requirements of the ACTION are not met. This requirement in ACTION a. has been changed to note that a transition from ACTION a. to ACTION b. is required specified actions are not taken. ACTION b. has been revised to if other require the unit to ultimately be in HOT SHUTDOWN (MODE 4) other actions are not taken. T/S 3.7.1 applies only in MODES 1, 2, if the and 3; therefore, the current direction to go to COLD SHUTDOWN (MODE

5) is considered to be inappropriate.

10 CFR 50 92 CRITERIA Per 10 CFR 50.92, a proposed change does not involve a significant hazards consideration if the change does not:

involve a significant increase in the probability or consequences of an accident previously evaluated,

2. create the possibility of a new or different kind of accident from any accident previously evaluated, or

3. involve a significant reduction in a margin of safety.

Attachment 1 to AEP:NRC:1213 Page 3 Criterion 1 Correction of the setpoint methodology does not represent a credible accident initiator. The new methodology reduces the allowable power level setpoints and is conservative compared to the presently evaluated setpoints. The consequences of any previously evaluated accident are not adversely affected by this action because the decrease in the setpoints resulting from the new calculational methodology will ensure that the MSSVs are capable of relieving the pressure at the allowable power levels. Based on these considerations, it is concluded that the changes do not involve a significant increase in the probability or consequences of an accident previously evaluated.

Correcting. the overly restrictive action statements of T/S 3.7.1 does not involve a significant increase in the probability of an accident. The proposed changes modify existing text to more accurately reflect the intention of the restrictions imposed by the action statements. The changes do not create any situation that would initiate a credible accident sequence.

Criterion 2 The change in Table 3.7-1 reduces the allowable power levels that can be achieved in the event that one or more main steam safety valve(s) is inoperable. This change is a result of vendor guidance to correct an error in the existing methodology used to determine the setpoints for the power level. Changing the methodology used to determine the setpoints, and lowering the setpoints themselves, do not create a new condition that could lead to a credible accident.

Therefore, it is concluded that the proposed changes do not create the possibility of a new or different kind of accident from any accident previously evaluated.

The action statements remain in effect to perform the intended function of protecting the plant's secondary side when the main steam safety valves are inoperable. They have only been modified to correct the overly restrictive language that specifies when, in each MODE, specific actions must be taken. Therefore, the proposed change does not create a new or different type of accident.

Criterion 3 The margin of safety presently provided is not reduced by the proposed change in the setpoints. The change will correct the limiting power levels that are to be implemented when MSSVs are inoperable. This action does not adversely affect the margin that to AEP:NRC:1213 Page 4 was previously allocated for the ability of the MSSVs to relieve secondary side pressure. Based on these considerations, it is concluded that the changes do not involve a significant reduction in a margin of safety.

The margin of safety is also not significantly reduced by the proposed change to the action statements of the T/S. The proposed revision clarifies when specific actions are to be taken in response to inoperable main steam safety valves. The changes do not decrease the effectiveness of the actions to be taken; therefore, they do 'not significantly reduce any margin of safety.