ML20149H092

Application for Amend to License NPF-1,consisting of License Change Application 164.Amend Revises Operability & Surveillance Requirements & Bases for Component Cooling Water Sys

ML20149H092
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	02/04/1988
From:	Cockfield D PORTLAND GENERAL ELECTRIC CO.
To:
Shared Package
ML20149H082	List: ML20149H079 ML20149H092 ML20149H112
References
TAC-67161, NUDOCS 8802190107
Download: ML20149H092 (10)

Text

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PORTLAND CENERAL ELECTRIC COMPANY EUGENE WATER & ELECTRIC BOARD AND PACIFIC POWER & LICHT COMPANY 4

Operating License NPF-1 ,

Docket 50-344 i License Change Application 164 l

This License Change Application requests changes be made to Section 3/4.7.3.1 and 3/4.7.3.2 of the Trojan Technical Specifications, i Appendix A to Operating License NPF-1, for the Trojan Nuclear Plant.

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PORTLAND CENERAL ELECTRIC COMPANY By,- 3 k) .

D. W. Cockffeld Vice President Nuclear '

Subscribed and sworn to before me this 4th day of February 1988.

to bk Notary Public of Oregon r$1L.

My Comission Expires: u<s I M /I7/

i 8802190107 880204 PDR ADOCK 05000344 P DCD i

LCA 164 Page 1 of 9 Reason for Change References 1 and 2 discussed a Nuclear Regulatory Commission (NRC) concern regarding the ability of the Component Cooling Water (CCW) System to remain functional following a seismic event. During the August 1986 Safety System Functional Inspection of Trojan, the NRC determined that automatic isolation of the Non-Seismic Category I portion of the CCW System may not occur in time to prevent blowdown of both trains. The NRC determined that the design basis for pipe ruptures in the CCW System was a full area break.

As a result of the NRC findings, Portland General Electric (PGE) com-mitted to upgrade the CCW System by either seismically supporting the non-seismic portions of the system, or installing a flow orifice which will restrict flow and indicate high flow conditions which will activate closure of the train isolation valves. This commitment is documented in Reference 3. PGE committed to complete this upgrade by no later than the 1989 refueling outage. Until that time, the CCW Syatem will be operated in a "split-train" configuration with the interf ace isolation valves for one train normally closed and with all three CCW pumps maintained in an operable status.

The NRC accepted PGE's course of action, as described above, in their letter dated December 15, 1987 (Reference 4) on the condition that the Trojan Technical Specifications be revised. This revision was stated as necessary to provide the same level of protection and safety in the proposed configuration as that of the current Technical Specifications.

This License Change Application (LCA) is submitted to provide the proposed Technical Specification changes for the CCW System ss required by the NRC.

Description of Chante The proposed changes are to Trojan Technical Specification 3/4.7.3.1 and 3/4.7.3.2 and associated bases.

1. Chantes to Technical Specification 3/4.7.3.1:

a. The limiting condition for operation (LCO) currently states:

"3.7.3.1 At least two independent component cooling water loops shall be OPERABLE.

"APPLICABILITY: MODES 1, 2, 3 and 4 "ACTION: With only one component cooling water loop OPERABLE, restore at least two loops to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in COLD SHUTDOWN within the next 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />."

LCA 164 Page 2 of 9 This LCO will be changed to read as follows:

"3.7.3.1 At least two independent component cooling water loops shall be OPERABLE, with one train isolated from Seismic Cate-gory II loads. The spare component cooling water pump shall be OPTRABLE.

"APPLICABILITY: MODES 1, 2, 3 AND 4.

"ACTION: With the spare pump inoperable, restore the spare pump to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> er be in COLD SHUTDOWN within the next 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

"With only one component cooling water train and spare pump OPERABLE, restore the other train to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in COLD SHUTDOWN within the next 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />."

b. The Surveillance Requirements currently state:

"4.7.3.1 At least two component :ooling water loops shall be demonstrated OPERABLE:"

This statement will be changed to read as follows:

"4.7.3.1 The component cooling water system shall be demonstrated OPERABLE:"

Also, two new paragraphs will be added as follows:

"f. At least once per 31 days by verifying that either valves CV-3304 and CV-3288 or CV-3303 and CV-3287, are closed.

"g. At least once per 92 days by verifying that power can be supplied to the spare CCW pump from both buses."

2. Chantes to Technical Specification 3/4.7.3.2:

a. The LCO currently states:

"3.7.3.2 At least one component cooling water train capable of supplying cooling water to equipment needed in MODES 5 and 6 shall be OPERABLE.

"APPLICABILITY: MODES 5 and 6 "ACTION: With less than the required number of component cooling water trains OPERABLE, declare supported equipment inoperable."

LCA 164 Page 3 of 9 This LCO will be changed to read as follows:

"3.7.3.2 At least two component cooling water trains capable of supplying cooling water to equipment needed in MODES 5 and 6, or at least one train and the spare component cooling water pump, shall be OPERABLE.

"APPLICABILITY: MODES 5 and 6 "ACTION: With less than the required numbur of component cooling water trains OPERABLE, declare supported equipment inoperable.

"With only one component cooling water train OPERABLE and the spare pump inoperable, declare supported equipment inoperable."

b. The Surveillance Requiremento currently state:

"4.7.3.2 At least one component cooling water train shall be demonstrated OPERABLE . . .

This Surveillance Requirement will be changed to read as follows:

"4.7.3.2 At least two component cooling water trains or one train and the spare component cooling water pump, shall be demonstrated OPERABLE . . ."

3. Chant.es to Technical Specification Bases 3/4.7.3:

The following paragraphs will be added to the CCW Technical Specification Bases.

"The OPERABILITY of the CCW System with one train isolated from Seismic Category II loads ensures that sufficient cooling capacity is available for continued operation of safety-related equipment following a seismic event. The OPERABILITY of the I

spare CCW pump ensures the availability of a CCW loop even with a single-failure concurrent with a seismic event.

"Operation in Modes 1 through 4 is permitted with one CCW train inoperable for up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> provided the spare CCW pump is

' OPERABLE. During this 72-hour time period, the OPERABLE CCW train should not be isolated from Seismic Category II loads to ensure a continuous supply of CCW cooling to the reactor coolant pumps. The spare CCW pump is considered OPERABLE provided Surveillance Requirements 4.7.3.1.b and 4.7.3.1.g have been mat."

The changes are shown in the attachment to this LCA.

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!- LCA 164 page 4 of 9 t

Detailed Safety Evaluation Trojan Technical Specifications 3/4.7.3.1 and 3/4.7.3.2 are proposed to be revised to require a split train operating configuration and operabil-ity of the spare pump for the CCW System. This revision is necessary to provide a level of protection and safety, in the new configuratica, comparable to that intended by the current Technical Specifications.

The CCW System provides heat removal f rom safety-related and non-safety-related components during norum1 operation, shutdown and cooldown of the reactor, and from safety-related components after any accident leading to an emergency shutdown. In addition, the CCW System provides a monitored, intermediate barrier between Reactor Coolant System (RCS) and the heat sink provided by the Service Water System (SWS). The portion of the CCW System that supplies cooling water to Engineered Safety Feature (ESF) equipment, is safety-related and complies with the appropriate regulatory requirements with regard to design, equipment qualification, redundancy and separation. s The CCW System consists of two Seismic Category I flow paths, each of which serves a single train of identical ESF equipment. In addition, each of the Seismic Category I flow paths se'Ives a common Non-Seismic Category I, non-safety-related flow path. Each CCW train has air-operated interface isolation valves to provide automatic isolation of the Seismic Category I portion of the system from the Non-Seismic Category I portion of the system upon receipt of a safety injection signal (SIS) or a low CCW surge tank level signal. One purpose of this autonatic isolation capability is to ensure that the failure of Non-Seismic Category I equip-ment and components (including piping) does not adverriely affect the operation of ESF equipment essential to safe shutdown of the plant.

Given a full area rupture of the Non-Seismic Category I piping due to a seismic event, it has been determined that the automatic interface isola-tion valves may not close fast enough to prevent blowdown of the safety-related portion of the two CCW trains. This could result in a complete loss of CCW. To preclude this scenario from occurring, the CCW System has been aligned in a split-train configuration with one train isolated from the Non-Seismic Category I flow path during Modes 1 through 4 This configuration ensures a continuous flow of CCW to at least ons train of ESF equipment following a seismle event.

In addition to aligning the CCW System in a split-train configuration, the spare CCW pump will be maintained operable during Modes 1 through 4.

This will assure the availability of a CCW loop even with a single-failure concurrent with a seismic event.

irm . . .

2 LCA 164 page 5 of 9 In accordance with 10 CFR 50.59, LCA 164 is judged to present no unreviewed safety question based on the followint:

1. The changes proposed in this LCA do not increase the probability of occurrence or the consequences of an accident or malfunction of equipment important to safety previously evaluated in the safety

, analysis report.

The accident scenario of concern is a loss of all CCW due to a seismic-induced rupture of the Non-Seismic Category I CCW piping.

With the CCW flow paths in their original configuration, the probability of loss of all CCW would be higher than with the system in a split-train configuration. Isolating one train of CCW from the Non-Seismic Category I flow path during Modes 1 through 4 provides greater assurance of CCW supply to safe shutdown loads following a seismic event.

Maintaining the spare CCW pump operable in Modes 1 through 4 assures that a CCW loop can be made available even if a single-failure is assumed to occur concurrent with a seismic event. This provides greater assurance of CCW availability than the current Technical Specification requirement.

During Modes 5 and 6, the proposed change will require that 5t least two CCW trains, or at least one CCW train and the spare CCW iJmp, be operable. This provision is an enhancement over the current provi-sions in the Technical Specifications and therefore will provide greater assurance of CCW restoration following a seismic event.

Also, because the plant is in at least a cold shutdown conditicn during these modes and timely recovery actions can be expected, the consequences of a seismically induced failure are bounded by current Final Safety Analysis Report (USAR) accident analyses.

Since the proposed changes enhance the availability of CCW following a seismic event, the probability and consequences of an accident or malfunction are not increased.

l 2. The changes do not create the possibility for an accident or malfune-l tion of a different type than any previously evaluated in the safety analysis report.

Operating the CCW System in a split-train configuration during Modes 1 through 4, as previously described, ensures that there will be a continuous supply of cooling water to safe shutdown equipment following a seismic event. In the event of an earthquake and single active failure, the spare CCW pump will be available to supply CCW to safe shutdown equipment.

A Design Basis Accident (DBA) is not assumed to occur simultaneously with a seismic event that ruptures the Non-Seismic Category I CCW l

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LCA 164 Page 6 of 9 1 .

piping. Therefore, at least one train of ESF equipment would be available to respond to accident demands assuming a single-failure in the other train with the CCW System aligned in a split-train configuration.

During Modes 5 and 6, the proposed change will require that at least two CCW trains, or at least one CCW train and the spare CCW pump, be operable. This provision is an enhancement over the current provi-sions in the Technical Specifications. Since this change provides greater assurance of CCW System restoration following any seismic-induced failures in the Non-Seismic Category I portion of ths system, an accident or malfunction of a different type will not be created.

In summary, the changes proposed provide greater assurance that CCW will be available to supply safe shutdewm equipment than does opera-tion in the original lineup. Therefore, the proposed changes will not result in the creation of an accident or malfunction of a different type than previously evaluated in the FSAR.

3. The changes do not reduce the margin of safety as defined in the basis for any Technical Specification.

Changing the operation of the CCW System to a split-train configura-tion during Plant operating modes provides greater assurance that CCW will be available in the event of a seismically induced rupture in the Non-Seismic Category I CCW piping than does operation in the original lineup. Providing additional controls on maintaining operability of the spare CCW pump also provides greater assurance of CCW System availability assuming a single-failure occurs concurrent with the seismic event. Therefore, no margins of safety are reduced.

Environmental Evaluation The described change does not affect Plant discharges to the environment and consequently does not present an unreviewed environmental question.

$ Significant Hazards Determination Trojan Technical Specifications 3/4.7.3.1 and 3/4.'7.3.2 are proposed to be revised to require a split train operating configuration and operabil-ity of the spare pump for the CCW System. This revision is necessary to provide a level of protection and safety, in the new configuration, comparable to that intended by the current Technical Specifications. (

The CCW System provides heat removal from safety-related and non-safety-related components during norval operation, shutdown and cooldown of the 1

reactor, and from safety-related components after any accident leading to an emergency shutdown. In addition, the CCW System provides a monitored, intermediate barrier between RCS and the heat sink provided by the SWS.

LCA 164 page 7 of 9 The portion of the CCW System that supplies cooling water to ESF equip-ment, is safety-related and complies with the appropriate regulatory requirements with regard to design, equipment qualification, redundancy and separation.

The CCW System consists of two Seismic Category I flow paths, each of which servsa a single train of identical ESF equipment. In addition, each of the seismic Category I flow paths serves a common Non-Seismic Category I, non-safety-related flow path. Each CCW train has air-operated interface isolation valves to provide automatic isolation of the Seismic Category I portion of the system from the Non-Seismic Category I portion of the system upon receipt of an SIS or a low CCW surge tank level signal. One purpose of this automatic isolation capability is to ensure that the failure of Non-Seismic Category I equipment and components (including piping) does not adversely affect the operation of L3F equipment essential to safe shutdown of the plant.

Given a full area rupture of the Non-Seismic Category I piping due to a seismic event, it has been determined that the automatic interface isola-tion valves may not close fast enough to prevent blowdown of the safety-related portion of the two CCW trains. This could result in a completo loss of CCW. To preclude this scenario from occurring, the CCW System has been aligned in a split-train configuration with one train isolated from the Non-Seismic Category I flow path during Modes 1 through 4. This configuration ensures a continuous flow of CCW to at least one train of ESF equipment following a seismic event.

In addition to aligning the CCW System in a split-train configuration, the spare CCW pump will be maintained operable during Modes 1 through 4.

This will assure the availability of a CCW loop even with a single-failure concurrent with a seismic event.

In sccordance with 10 CFR 50.92, LCA 164 is judged to involve no significant hazards considerations based on the following:

1. The changes proposed in this LCA do not significantly increase the l probability or consequences of an accident previously evaluated.

The accident scenario of concern is a loss of all CCW due to a seismic-induced rupture of the Non-Seismic Category I CCW piping.

I With the CCW flow paths in their original configuration, the probability of loss of all CCW would be higher than with the system in a split-train configuration. Isolating one train of CCW from the Non-Seismic Category I flow path during Modes 1 through 4 provides greater assurance of CCW supply to safe shutdown loads following a i seismic event.

l l Maintaining the spare CCW pump operable in Modes 1 through 4 assures that a CCW loop can be made available even if a single-failure is assumed to occur concurrent with a seismic event. This provides l

LCA 154 page 8 of 9 greater assurance of CCW availability than the current Technical Specification requirement.

During Modes 5 and 6, the proposed change will require that at least two CCW trains, or at least one CCW train and the spare CCW pump, be operable. This provision is an enhancement over the current provi-sions in the Technical Specifications and therefore will provide greater assurance of CCW restoration following a seismic event.

Also, because the plant is in at least a cold shutdown condition during these modes and timely recovery actions can be expected, the consequences of a seismically induced failure are bounded by current FSAR accident analyses.

Since the proposed changes enhance the availability of CCW following a seismic event, the probability and consequences of an accident previously evaluated are not increased.

2. This proposed LCA does not create the possibility of a new or different kind of accident from any previously evaluated.

Operating the CCW System in a split-train configuration during Modes 1 through 4, as previcusly described, enrures that there will be a continuous supply of cooling water to safe shutdown equipment following a seismic event. In the event of an earthquake and single active failure, the spare CCW pump will be available to supply CCW to safe shutdown equipment.

A DBA is not assumed to occur simultaneously with a seismic event that ruptures the Non-Seismic Category T CCW piping. Therefore, at least one train of ESF equipment would be available to respond to accident demands assuming a single-failure in the other train with the CCW System aligned in a split-train configuration.

During Modes 5 and 6, the proposed change will require that at least two CCW trains, or at least one CCW train and the spare CCW pump, be operable. This provision is an enhancement over the current provi-sions in the Technical Specifications. Since this change provides

, greater assurance of CCW System restoration following any seismic-inouced failures in the Non-Seismic Category I portion of the system, an accident of a new or different kind from any previously evaluated will not be created.

In summary, the changes proposed provide greater assurance that CCW will be available tc supply safe shutdown equipment than does opera-tion in the original 2'.neup. Therefore, the proposed changes will not result in the creation of an accident of a new or different kind than previously evaluated.

LCA 164 Page 9 of 9

3. This proposed LCA does not involve a significant reduction in a margin of safety.

Changing the operation of the CCW System to a split-train configura-tion during Plant operating modes provideo greater assurance that CCW will be available in the event of a seismically induced rupture in the Non-Seismic Category I CCW piping than does operation in the original lineup. Providing additional controls on maintaining operability of the spare CCW pump also provides greater assurance of CCW System availability assuming a single-failure occurs concurrent with the seismic event. Therefore, no margins of safety are reduced.

In the March 6, 1986 Fe,deral Register, the NRC provided certain examples of amendments that are considered not likely to involve a significant hazards consideration. Example 2 from that list states:

"A change that constitutes an additional limitation, restriction, or control not presently included in the Technical Specifications, eg, a more stringent surveillance requirement."

This example is deemed to apply to the change proposed herein.

l For the reasons described above, it is PGE's determination that the proposed Technical Specification changes provide greater protection than the current Technical Specifies tions and do not involve a significant I hazards consideration.

References

1. NRC letter to PGE, Failure Mode of Non-seismic Category I Piping at Trojan, April 2, 1987.

2. TGE letter to NRC, Failure Mode c' Non-seismic Category I Piping at Trojan, May 6,1987.

3. PGE letter to NRC, Component Cooling Water System. December 4, 1987.

4. NRC letter to PGE Trojan Technical Specifications - Component Cooling Water System December 15, 1987.

KLB/kal 6060k.188

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