ML20210A473

Proposed Tech Specs Reflecting Provisions for Testing Shunt Trip Attachments & Silicon Controlled Rectifier Relays

ML20210A473
Person / Time
Site:	Rancho Seco
Issue date:	11/08/1985
From:	SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:
Shared Package
ML20210A452	List: ML20210A448 ML20210A473
References
NUDOCS 8511150042
Download: ML20210A473 (15)

Text

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. rat 4CHU SECO UalT 1 TECHNICAL SPECIFICAT10NS b

- Limiting Conditions for Operation 3.5 INSTRUMENTATION SYSTEt4S

'3.5.1 OPERATIONAL SAFETY INSTRut4Et4TATI0t4 Applicability , ,

Applies to unit instrumentation and control systems.

Objective .

To delineate the conditions of the unit instrumentation and safety circuits necessary to assure reactor safety.

Specifications 3.5.1.1 Startup and operation are not permittea unless the requirements of l table 3.5.1-1, Columns A and B are met.

3.5.1.2 In the event the number of protection channels operable falls below the limit given under taDie 3.5.1-1, Columns A and B, operation shall be limited as specified in Column C.

In the event the number of operable Process Instrumentation channels is less than the Total Number of Channel (s), restore the inoperable channels to c erable status within 7 days, or be in at least hot shutdown witnin the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. If the number of operable channels is less than the minimum channels operable, either restore the inoperable cpannels to operaole within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or be in at least .

hot shutdown within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

• 7 3.5.1.3 For on-line testing or in tae event of a protection . instrument or channel failure, a key operated channel bypass switch associated with each reactor protection channel will be used to lock the channel trip relay in the untripped state as indicated by a light. Only one channel shall be locked in this untripped state at cny one time.

3.5.1.4 The key operated shutdown bypass switch associated with each reactor protection channel shall not be used during reactor power operation.

3.5.1.5 During startup when the intermediate range instrument comes on scale, tne overlap between the intermediate range ano tne source range instrumentation shall not be less than one decade. If the <%erlap is less than one decade, tne flux level snall be maintained in the source range until the one decade overlap is achieved.

i 114> 3.5.1.6 tiith one of the Reactor Trip Breaker diverse trip features l

(undervoltage or shunt trip attachment) inoperable, restore it to j OPERABLE status in 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or place the breaker in trip in the next  ;'

< hour. .

Proposed Amendment No.114, Revision 1 3-25 i 0511150042 DR 85110B ADOCK 05000312 FDR , ,

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'- RANCHO SECO UNIT 1

,4 TECHNICAL SPECIFICATIONS Limiting Conditions for Operation 114> 3.5.1.7 In the event that both Reactor Trip Breaker diverse trip features fail in the untripped state, the Breaker will be declared IN0PERABLE, and the power supplied to the rod drive mechanisms through the failed trip device shall be manually removed within 30 minutes. The condition will be corrected and the remaining trip devices shall be tested within eight hours. If the condition is not corrected and the remaining trip devices are not tested within the eight-hour period, the reactor shall be placed in the hot shutdown condition within an additional four hours.

3.5.1.8 The SCR relays for the regulating rods duplicate the trip function of the DC breakers for the safety rods. With the number of operable SCR relays one less than the total number of SCR relays in a channel, restore the inoperable SCR relay to operable status in 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or place the SCRs associated with the inoperable relay in trip in the next hour.

3.5.1.9 The IN0PERABLE channel in Sections 3.5.1.6, 3.5.1.7, and 3.5.1.8 may be bypassed for up to 30 minutes in any 24-hour period when necessary

< for surveillance testing per Specification 4.1.1.

Proposed Amendment No. 114, Revision 1 3-25a

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RANCHO SECO UNIT 1 TECHNICAL SPECIFICATI0i4S Limiting Conditions for Operation Bases Every reasonable effort will be maae to maintain all safety instrumentation in operation. A startup is not permitted unless three power range neutron instrument channels and two cnannels each of the following are operable: four reactor coolant temperature instrument channels, f,our reactor coolant flow instrument channels, four reactor coolant pressure instrument cnannels, feur pressure-temperature instrument channels, four flux-imbalance flow instrument channels, four power-number of pumps instrument cnannels, and four high reactor building pressure instrument channels. The safety features actuation system must have two analog channels functioning correctly prior to startup.

Operation at rated power is pennitted as long as the systems have at least the redundancy requirements of Column B. (Table 3.5.1-1). This is in agreement with redundancy and single failure criteria of IEEE 279 as described in FSAR section 7.

There are four reactor protection cnannels. Normal trip logic is two out of four. Required trip logic for the power range instrumentation channels is two out of three. Minimum trip logic on other instrumentation channels is one out of two.

The four reactor protection channels were provided with key operated bypass switches interlocked to allow on-line testing or maintenance on only one channel at a time during power operation. Each channel is provided alarm and lights to indicate wnen tihat channe1 is bypassed.

Each reactor protection channel key operated shutdown oypass switen is provided with alarm and lights to indicate when the shutdown bypass switch is being used. There are four snutdown bypass Keys in tne control room under the administrative control of the shift supervisor. The keys will not be used during reactor power operation.

The source range and intennediate range nuclear flux instrumentation scales overlap by one decade. This decade overlap will De achieved at 10-10 amps on the intermediate range scale.

Power is normally supplied to the control rod drive mechanisms from two separate parallel 480 volt sources. Redundant trip devices are employed in each of these sources. If any one of these trip devices fails in the untripped state on-lina repairs to the failed device, when practical, will be 114> made. If on-line repairs are not practical, the device will be replaced with

< a spare or placed in tripped condition in a timely manner.

Tne OPERABILITY of the SFAS instrumentation systems and bypasses ensure that

1) the associated SFAS action will be initiated when the parameter monitored by eacn channel or comoination thereof reacnes its setpoint, 2) the specified coincidence

< Proposed Amendment. No.114, Revision 1 3-2b

r- ,. =4 RANCHO SECO UNIT 1 -

TECHNICAL SPECIFICATIONS . .:

Surveillanca Standards

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Tr_blo 4.1-1 (Continued)- ,

. INSTRUPENT SURVEILLANCE REQUIREMENTS Channel Description Check Test Calibrate Remarks-

8. Reactor coolant pressure /

temperature comparator S M R

9. Power / imbalance / flow comparator S M R

10. Pump / flux comparator S M R

11. High Reactor Building Pressure Channels D M R 114> 12a. Protection channel coincidence logic NA M NA

b. ARTS Turbine Trip S M R Monitor Channels

c. ARTS Loss of WW Pumps S M R Monitor Channels 13a. CRD Trip Breaker RPS Undervoltage trip NA M NA

b. RPS Shunt Trip NA M NA 4 c. SCR Relays NA M NA Safety Features System

14. Emergency core cooling injection, emergency building cooling and building isolation analog channels

a. Reactor coolant pressure channel S M R

b. Reactor Building 4 psig channel S M R Proposed Amendment No. 114. Revision 1 4-4

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ATTACMENT III a.

B&W Owners Group Comment on Revised Standard Technical Specifications Pertainina to Silicon Controlled Rectifiers i

NRC's Generic Letter 85-10 provides revised standard Technical Specifications applicable to B&W plants pertaining to two items

' addressed by Generic Letter 83-28 on the generic implication of the Salem ATWS event. These include Item 4.3 on the reactor trip breaker shunt trip attachment and Item 4.4 on the control rod drive control system Silicon Controlled Rectifier (SCR) relays.

Based on a review of these revised Technical Specifications, the

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B&W Owners Group has the following comment pertaining to SCR relays:

Table 3.3-1 has been revised to include a new Item 15 which defines operability requirements for the SCR relays and applies Action Statement 7 for the Oconee class design. With the definition for SCR channel contained in the Table, the wording of Action Statement 7 encompasses SCRs in all control rod groups even though a failure may - and in most cases will - be limited to one SCR relay affecting only one group.

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In the judgement of the B&W Owners Group this wording will result in the intentional tripping of equipment which has not failed. Such action will significantly increase the likeli-

- hood of inadvertent rod drops resulting in unneeded challenges to other plant safety systems.

. Additionally, with both the safety rods and other unaffected regulating rod groups available to shut down the reactor, the B&W Owners Group believe that 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> should be allowed for restoring the operability of an inoperable SCR relay.

For these reasons, the B&W Owners recommend that Action Statement 7 be removed from applicability for the Oconee class

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design in Item 15 .and a new Action Statement 11 be substi-tuted. Action Statement 11 should be worded as follows:

Action 11 .With the number of operable SCR relays one less.than the total number of SCR relays in a channel, restore the inoperable SCR relay to operable status in 48' hours or place the SCRs' associated with the inoperable relay in trip in the next hour.

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V esuuo SACRAMENTO MUNICIPAL UTIUTY DISTRICT O 6201 S Street, P.O. Box 15830 Sacramento CA 95852 1830,1916) 452 3211 AN ELECTRIC SYSTEM SERVING THE HEART OF CALIFORNIA RJR 85-534 November 6, 1985 DIRECTOR OF NUCLEAR REACTOR REGULATION ATTENTION HUGH L THOMPSON JR DIRECTOR -

DIVISION OF LICENSING U S NUCLEAR REGULATORY COMMISSION WASHINGTON DC 20555 DOCKET N0. 50-312 LICENSE N0. DPR-54 PROPOSED AMENDMENT NO. 114, REVISION 1 In accordance with 10 CFR 50.59, The Sacramento Municipal Utility District proposes to amend its Operating License DPR-54 for Rancho Seco Nuclear Generating Station Unit 1. Enclosed is Proposed Amendment No. 114, Revi-sion 1. Attachment I to this submittal is the No Significant Hazards Evaluation in accordance with 10 CFR 50.92.

This proposal is in response to Generic Letter 85-10 and supersedes the previous Proposed Amendment No. 114, dated October 19, 1984, in its antirety.

Pursuant to 10 CFR 50.91(a), we have provided a copy of this letter, the proposed change in technical specifications, and our analyses of Significant Hazards Considerations to Joseph Ward, the designated representative of the State of California.

Since this is a revision to Proposed Amendment No. 114, no additional license fees are required.

If you have any questions concerning this proposal, please contact Mr. Ron omEd at Rancho Seco Nuclear Generating Station.

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R. J. ODRIG Z ASSISTANT GEN RAL MANAGER, NUCLEAR Enclosures 3 s da b , 1985 "

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p. #A a camisna.ua.:uin.a.a. n.i:n.tse ,agmatsauinnu:ce RANCHO SECO NUCLEAR GENERATING STATION ' 1444o Twin Cities Road, Herald, CA 95638 9799;(209) 333 2935 s

r ATTACHMENT I SAFETY ANALYSIS As a result of Generic Letter 83-28, an automatic shunt trip attachment has been installed and technical specifications have been revised to include pro-visions for testing the shunt trip attachment and the SCR relays. Rancho Seco Technical Specifications have been modified according to the guidelines contained in Generic Letter 85-10. Generic Letter 85-10 presents acceptable changes in the form of Model Standard Technical Specifications (STS). Pre-viously, there were no requirements for testing the SCR relays, therefore, the sections on SCR relays from the Model STS have been inserted into Rancho Seco Technical Specifications. However, the Model STS action statement for SCR relays has been modified according to the B&W Owners Group comments con-tained in Attachment III. The sections on the shunt trip attachment have been incorporated into the existing specifications for the reactor trip breakers. Originally, reactor trip breaker LCO statements only dealt with the undervoltage device, that is if the UV device fails, the breaker will not operate. Now with the addition of the shunt trip which acts in parallel to the UV device, both trip features must fail in order for the breaker not to open. If this unlikely event were to occur, the original LC0 statements would apply and are, therefore, retained. With one of the diverse trip features failed, the breaker is still capable of operating and the Model STS guidelines for this situation have been incorporated into the Rancho Seco Technical Specifications.

NO SIGNIFICANT HAZARDS CONSIDERATIONS These proposed changes provide additional operational requirements to assure redundant and diverse reactor shutdown capability. All of the changes man-dated by Generic Letter 85-10 have been met by incorporating sections of Model Standard Technical Specifications along with the comments of the B&W Owners Group on SCR relays. Therefore, operation of Rancho Seco in accordance with this proposed amendment:

1. does not involve a significant increase in the protability or consequences of an accident previously evaluated,

2. does not create the possibility of a new or different kind of accident from any accident previously evaluated, and

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

Therefore, significant safety hazards are not associated with this Proposed Amendment.

ATTACHMENT II DESCRIPTION OF PROPOSED CHANGES

1. Page 3-25, Specification 3.5.1.6; Action Statement 9 from Table 3.3-1 of Generic Letter 85-10 has been inserted here.

2. Page 3-25a, Specification 3.5.1.7; This was formerly Specification 3.5.1.6.

Minor changes have been made to the first sentence of this specification in order to account for the fact that the reactor trip breakers now have two diverse trip features.

3. Page 3-25a, Specification 3.5.1.8; Based upon the guidance of the B&W Owners Group, this Specification on SCR Limiting Conditions for Operation has been proposed.

4. Page 3-25a, Specification 3.5.1.9; The portions of Action Statement 7b that apply to the reactor trip breakers and the SCRs have been retained in this specification. Those that pertain to the reactor trip modules have not been included.

5. -Page 3-26, 7th paragraph of the Bases; The last sentence describes main-tenance responses to a failure of one of the diverse trip features.

6. Page 4-4, Items 12 and 13; Surveillance requirements for the ARTS inputs have been removed from Item 13 and placed under Item 12. Surveillance requirements for the SCR relays and the shunt trip device have been inser-ted under Item 13.

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~ l rat 4CHU SELO Ud1T 1 TECHNICAL SPECIFICATI0t4S e

Limiting Conditions for Opsration 3.5 INSTRUMENTATION SYSTEMS 3.6.1 OPERATIONAL SAFETY INSTRUMEt4TATI0td Applicability , ,

Applies to unit instrumentation and control systems.

Objective To delineate the conditions of the unit instrumentation and safety circuits necessary to assure reactor safety.

Specifications 3.5.1.1 Startup and operation are not permittea unless the requirements of table 3.5.1-1, Columns A and B are met.

3.5.1.2 In tne event the number of protection channels operable falls below the limit given under table 3.5.1-1, Columns A and B, operation sna11 be limited as specified in Column C.

In the event the number of operable Process Instrumentation channels is less than tne Total Number of Channel (s), restore the inoperable channels to operable status within 7 days, or be in at least hot shutdown within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. If the number of operable channels is less than the minimum channels operable, either restore the inoperable cpannels to operaDie witnin 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or be in at least hot shutdown within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

• 3.5.1.3 For on-line testing or in the event of a protection . instrument or channel failure, a key operated channel bypass switch associated with each reactor protection channel will be used to lock the channel trip relay in the untripped state as indicatea by a light. Only one channel shall be lockea in this untripped state at any one time.

3.5.1.4 The key operated shutdown bypass switch associated with ucn reactor protection channel shall not be used during reactor power operation.

3.5.1.5 During startup when the intermeciate range instrument comes on scale, tne overlap between the intermediate range ano tne source range instrumentation shall not be less than one decade. If the overlap is less than one decade, tne flux level snall be maintained in the source range until the one decade overlap is achieved.

11b 3.5.1.6 With one of the Reactor Trip Breaker diverse trip features (undervoltage or shunt trip attachment) inoperable, restore it to OPERABLE status in 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or place the breaker in trip in the next i < hour. .

Proposed Amendment No.114, Revision 1 3-25 l

RANCHO SECO UNIT 1 TECHNICAL SPECIFICATIONS Limiting Conditions for Operation 114> 3.5.1.7 In the event that both Reactor Trip Breaker diverse trip features fail in the untripped state, the Breaker will be declared INOPERABLE, and the power supplied to the rod drive mechanisms through the failed trip device shall be manually removed within 30 minutes. The condition will be corrected and the remaining trip devices shall be tested within eight hours. If the condition is not corrected and the remaining trip devices are not tested within the eight-hour period, the reactor shall be placed in the hot shutdown condition within an additional four hours.

3.5.1.8 The SCR relays for the regulating rods duplicate the trip function of the DC breakers for the safety rods. With the number of operable SCR relays one less than the total number of SCR relays in a channel, restore the inoperable SCR relay to operable status in 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or place the SCRs associated with the inoperable relay in trip in the next hour.

3.5.1.9 The INOPERABLE channel in Sections 3.5.1.6, 3.5.1.7, and 3.5.1.8 may be b/ passed for up to 30 minutes in any 24-hour period when necessary

< for surveillance testing per Specification 4.1.1.

Proposed Amendment No.114, Revision 1 3-25a

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RANCHO SEC0 UNIT A o TECHNICAL SPEClFICATIOt4S Limiting Conditions for Operation Bases ,

Every reasonaole effort will be maae to maintain all safety instrumentation in operation. A startup is not permitted unless three power range neutron instrument channels and two cnannels each of the following are operable: four reactor coolant temperature instrument channels, f,our reactor coolant flow instrument channels, four reactor coolant pressure instruaent cnannels, f.our pressure-temperature instrument channels, four flux-imbalance flow instrument channels, four power-number of pumps instrument cnannels, and four high .

reactor building pressure instrument channels. The safety features actuation system must have two analog channels functioning correctly prior to startup.

Operation at rated power is permitted as long as the systems have at least the redundancy requirements of Column B. (Table 3.5.1-1). This is in agreement witn redundancy and single failure criteria of IEEE 279 as described in FSAR section 7.

There are~ four reactor protection cnannels. Normal trip logic is two out of four. Required trip logic for the power range instrumentation channeis is two out of three. Minimum trip logic on other instrumentation channels is one out ,

of two.

The four reactor protection channels were provided with key operated bypass switches interlocked to allow on-line testing or maintenance on only one channel at a time during power operation. Each channel is provided alann and lights-to indicate wnen tpat channe1 ~is bypassed.

i- Each reactor protection channel key operated shutdown Dypass switen is provided with alarm and lights to indicate when the shutdown bypass switch is being used. There are four snutcown bypass keys in tne control room under the administrative control of the shift supervisor. The keys will not be used during reactor power operation.

The source range and intermediate range nuclear flux instrumentation scales overlap by one decade. This decade overlap will De achieved at 10-10 amps on the intermediate range scale.

Power is normally supplied to the control rod drive mechanisms from two

- separate parallel 480 volt sources. Redundant trip devices are employed in each of these sources. If any one of these trip devices fails in the untripped state on-line repairs to the failed device, when practical, will be 114r made. If on-line repairs are not practical, the device will be replaced with

< a spare or placed in tripped condition in a timely manner.

Tne OPERABILITY of the SFAS instrumentation systems and bypasses ensure that

1) the associated SFAS action will be initiated when the parameter monitored by eacn channel or comoination thereof reacnes its setpoint, 2) the specified coincidence Proposed Amendment No.114, Revision 1 3-26

RANCHO SECO UNIT 1 TECHNICAL SPECIFICATIONS Surysillrnce Standards Table 4.1-1 (Continued)

, INSTRUMENT SURVEILLANCE REQUIREMENTS Channel Description Check Test Calibrate Remarks

8. Reactor coolant pressure /

temperature comparator S M R ,3

9. Power / imbalance / flow comparator S M R

10. Pump / flux comparator S M R

11. High Reactor Building Pressure Channels D M R 114> 12a. Frotection channel coincidence logic NA M NA

b. ARTS Turbine Trip S M R Monitor Channels

c. ARTS Loss of W W Pumps S M R Monitor Channels 13a. CRD Trip Breaker RPS Undervoltage trip NA M NA

b. RPS Shunt Trip NA M NA

< c. SCR Relays NA M NA Safety Features System

14. Emergency core cooling injection, emergency building cooling and building isolation analog channels

a. Reactor coolant pressure channel S M R

b. Reactor Building 4 psig channel S M R Proposed Amendment No.114. Revision 1 4-4 i

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ATTACIE NT III B&W Owners Group Comment on Revised Standard I

! Technical Soecifications Pertaininct to Silicon Controlled Rectifiers NRC's Generic Letter 85-10 provides revised standard Technical Specifications applicable to B&W plants pertaining to two items l

addressed by Generic Letter 83-28 on the generic implication of the Salem ATWS event. These include Item 4.3 on the reactor trip breaker shunt trip attachment and Item 4.4 on the control rod drive control system Silicon Controlled Rectifier (SCR) relays.

Based on a review of these revised Technical Specifications, the B&W Ownerc Group has the following comment pertaining to SCR relays:

Table 3.3-1 has been revised to include a new Item 15 which defines operability requirements for the SCR relays and applies Action Statement 7 for the Oconee class design. With the definition for SCR channel contained in the Table, the wording of Action Statement 7 encompasses SCRs in all control rod groups even though a failure may - and in most cases will - be limited to one SCR relay affecting only one group.

In the judgement of the B&W Owners Group this wording will result in the intentional tripping of equipment which has not failed. Such action will significantly increase the likeli-hood of inadvertent rod drops resulting in unneeded challenges to other plant safety systems.

Additionally, with both the safety rods and other unaffected regulating rod groups available to shut down the reactor, the B&W Owners Group believe that 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> should be allowed for restoring the operability of an inoperable SCR relay.

For these reasons, the B&W Owners recommend that Action Statement 7 be removed from applicability for the Oconee class s

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9 design in Item 15 and a new Action Statement 11 be substi-tuted. Action Statement 11 should be worded as follows:

Action 11 - With the number of operable SCR relays one less than the total number of SCR relays in a channel, restore the inoperable SCR relay to operable status in 48' hours or place the SCRs associated with the inoperable relay in trip in the next hour.

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