ML20077G500

Safety Evaluation Supporting Amend 101 to License NPF-12

ML20077G500
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Site:	Summer
Issue date:	06/18/1991
From:	Office of Nuclear Reactor Regulation
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NUDOCS 9107010096
Download: ML20077G500 (7)

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.f SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 101 FACILITY OPERATING LICENSE NO. NPF-12 SOUTH CAR 0llNA ELECTRIC & GAS COMPANY SOUTH CAROLINA PUBLIC SERVICE AUTHORITY VIRGIL C. SUMMER NUCLEAR STATION, UNIT NO. 1 DOCKET NO. 50-395

1.0 INTRODUCTION

By letter dated December 12, 1990, South Carolina Electric & Gas Company (SCE&G or the licensee) requested an amendment to the Virgil C. Summer Station, Unit No. 1 (Summer Station) Techniral Specifications (TS). The proposed amendment would revise TS 3/4.3.1, Reactor Trip System Instrumentation, 3/4.3.2, Engineered Safety Feature Actuation System, and the associated Bases.

The proposed changes revise surveillance test intervals and allowed outage times for eactor trip system (RTS) and engineered safety features actuation system (ESFAS) instrumentation in accordance with the Westinghouse Electric Corporation technical report designated WCAP-10271.

In addition, the proposed changes request an extension of the allowed outage time for two functional units not specifically mentioned in WCAP-10271.

Finally, the proposed changes delete notes that are no longer applicable, correct typographical errors, and renumber items in a list. These last changes are administrative and have no safety rignificance.

A summary of the changes proposed by this amendment is presented below:

A.

TS 3/4.3.1 1)

Delete Note

• on Page 3/4 3-1.

This notation is no longer applicable.

TS 3/4.3.1, Table 3.3-1 1)

ACTION 6 is changed to be consistent with the Standard Technical Specifications (STS) ACTION 6 as this allows bypass for

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surveillance testing of other channels either for normal scheduled surveillance or surveillance necessary to determine if there is a common cause as required by the staff's SER on WCAP-10271, dated February 21, 1985.

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.- 2)

ACTION statements 2 and 10 are revised to increase the time that an inoperable RTS channel may be maintained in an untripped condition from 1 to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

3)

ACTION statement 2 is revised to increase the time that an inoperable RTS may be bypassed to allow testing of another channel in the same function from 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.

4)

Functional Unit 19.A.

In the APPLICABLE MODES column, the applicable note is changed from # to ##.

This corrects a typographicol error. Applicability is below P-6 in the STS and this is consistent with the MODE applicability in Table 4.3-1 for the same function.

5)

Notation ** is removed as it is not used.

Notation ****

superseded the use of Notation **.

6)

ACTION 12 is added to reflect the increased allowed outage time granted for the RTS and ESFAS trip logic (Functional Units 18 and 21) for maintenance and surveillance testing.

ACTION 8, which previously applied to these two functions, is retained with the original times as it is still applicable to the reactor trip breakers (Functional Unit 20).

C.

TS 3/4.3.1, Table 4.3-1 1)

Functional Unit 22. The first word of the function name is changed from " Restore" to " Reactor" to correct a typographical error.

2)

ANALO3 CHANNEL OPERATIONAL TEST surveillance requirements are changed from monthly to quarterly or to startup for Functional Units 2. 3, 4, 6, 7, 8, 9, 10, 11, 12, 13 and 14, as approved by the staff in its SER of February 21, 1985.

3)

The Surveillance Test Interval in Table 4.3-1 for Functional Unit 19, Reactor Trip System Interlocks, ANALOG CHANNEL OPERATIONAL TEST, is changed from monthly (A through F).

to at least once per 18 months for each of the six interlocks The monthly ANALOG CHANNEL OPERATIONAL TEST is deleted from hactional Unit 5.

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4)

Jable Notation (3) axial flux difference is changed to AXIAL FLUX DIFFERENCE as it is a defined term.

5)

Table Notation (1) is changed to 31 days, as has been I

generically approved.

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. 6)

Table Notation (8) is deleted since it is no longer used.

7)

Table Notation (9) is changed from monthly to quarterly.

8)

The trip actuating devise check is changed from monthly to quarterly for Functional Units 15 and 16.

D.

TS 3/4.3.2 1)

Note

• on Page 3/4 3-15a is deleted.

This notation is no longer dpplicable.

2)

ACTION statements have been changed to the format of the STS.

E.

TS 3/4.3.2, Table 3.3-3 l

1)

A new version of ACTION 19 has been added as ACTION 24 added to reflect the increased allowed outage time granted for the ESFAS trip functions for maintenance and surveillance testing. ACTION 24 allows 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> to place an inoperable channel into the tripped condition. Action 24 applies to Functional Units ic, Id, le, If, 4c, 4d, 4e, Sa and 6c.

I 2)

ACTION 15 is deleted as it is no longer used.

3)

ACTION statements 14 and 21 are revised to permit the approved 4-hour allowed outage time for surveillance testing and 12-hour allowed outage time for maintenance to be performed.

4)

Functional Unit 8.b. applicable ACTION is changed from ACTION 14 to ACTION 21.

5)

Allowed outage time for Functional Units 6.h and 8.a, ACTION 16, l

is increased, to be based on a plant-specific evaluation, l

F.

TS 3/4.3.2, Table 4.3-2 l

1)

The Surveillance Test Interval for ANALOG CHANNEL OPERATIONAL TEST is increased from once per month to once_per quarter for FunctionalUnitsic,Id,le,if,2c,3b(2),4c,4d,Sa,6c,6h, 8a, 9a and 9b.

2)

The Surveillance Test Interval for Functional Units b.h and 8.a is to be increased, based on a plant specific evaluation.

3)

Add new Functional Unit 6f and change the numbering in Unit 6 to be consistent with the numbering in Taisle 3.3-3.

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G.

TS-3/4.3.1 and 3/4.3.2 Bases Change the Bases to reference UCAp-10271 and supplements.

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. 2.0 EVALUATION By letter dated February 3,1983, Westinghouse forwarded WCAP-10271 for staff review.

This WC/P was prepared as a result of growing concern within the Westinghouse Owners Group over the impact of testing and maintenance requirements for plants, particularly as related to instrumentation systems.

Operational experience had shown that many inaovertent reactor trips and safeguards actuations causing unnecessary transients and challenges to safety systems have occurred during instrumentation maintenance. The members of the Westinghouse Owners Group maintained that a significant part of operations staff's time was spent performing, reviewing, documenting, and tracking surveillance activities that were unwarranted given the high reliability of the equipment.

WCAP-10271 stated that significant benefits for operating plants could be achieved through the revision of instrumentation maintenance requirements.

The staff, with the help of its contractor, Brookhaven National Laboratory, reviewed WCAP-10271 in a Safety Evaluation Report (SER) dated February 21, 1985. This SER approved quarterly RTS analog channel operational testing on a staggered basis, an increase in the time that an inoperable RTS analog channel may be maintained in an untripped condition from I hour to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, an increase in the time that an inoperable RTS analog channel may be bypassed to allow testing of another channel from 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, and testing of RTS analog channels in a bypassed condition.

By letter dated February 22, 1989, the staff issued an SER on Supplement 2 and Supplement 2, Revision 1, to WCAP-10271.

This SER approved (1) quarterly testing of ESFAS analog channels, (2) an increase in the allowed outage time for testing analog channels from 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, (3) an allowed outage time for testing of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> for all components in sclid state systems, (4) an increase in the allowed outage time for testing of le2ic trains and master relays to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, (5) an allowed outage time of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> for slave relays, (6) an allowed outage time for maintenance of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> for both relay and solid state systems, and (7) testing in bypass during the maintenance allowed outace time with an analog channel tripped after spending 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> in byptss.

Furthermore, this SER did not require a staggered test strategy for ESFAS analog testing and removed the requirement for a staggered test strategy for RTS analog channels.

l Finally, by letter dated April 30, 1990, the staff-issued a supplemental SER (SSER) on WCAP-10271, as supplemented and revised.

This SSER approved a surveillance test interval and allowed outage time extensions for functions l

associated with safety injection, steam line isolation, main feedwater isolation, and auxiliary feedwater pump start signals.

The SERs and the SSER were to be used for plant-specific approval of amendments to the RTS and ESFAS sections of the TS only if certain conditions were met.

The licensee addressed these conditions in their submittal as discussed below, i

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W 5-In the February 21, 1985, SER, the staff established the condition that approval of items related to extending surveillance test intervals is contingent on procedures being in place to require evaluation of failures:for conanon cause and to require additional testing if necessary, in response to this condition, SCE&G conunitted to implement enhancements to existing procedures to evaluate failures for common cause and to require additional testing as necessary.

These procedures will be developed using guidelines already approved by the staf f.

In the same SER, the staf f approved channel testing in a bypassed condition contingent on the capability of the RTS design to allow such testing without lif ting leads or installing temporary jumpers, in response to this condition, the licensee stated that they do not currently perform testing in bypass, but if they elect to do so in the future, plant modifications will first be made to allow such testing without lif ting leads or using temporary jumpers.

- The February 21,_1985, SER also states that an extension of RTS surveillance intervals is contingent on the licensee's confirmation that the instrument setpoint methodology includes sufficient margin to offset the drift anticipated as a result of less frequent surveillance.

In response to this condition, SCE&G confirmed that their methodology does account for such drift.

The licensee's design engineering of fice conservatively estimated maximum quarterly drift at.15 percent, whereas the TS trip setpoints are based on an error of.42 percent.

Therefore, instrument drif t over a three month period is not a significant factor.

Both the February 22, 1989, SER and the April 30, 1990, SSER contain the condition _that licensees must verify the applicability of the generic treatment of the issues in WCAP-10271' to their specific plant.

In response to this i

condit on, SCE&G stated that they use the Westinghouse 7300 Process Control System and the Westinghouse Solid State Protection System for both RTS and ESFAS.

Both of these systems were modeled in WCAP-10271.

The only functional units of the ESFAS that were not specifically modeled 'n the generic submittal were units 6h and 8a. These units were the subject of a plant-specific evaluation.

Finally, the latter two SERs required that the licensee confirm that any increase in ESFAS instrument drif t be accounted for in the setpoint ca lcu la tion.

Using the same documentation that they used-on RTS instrument

-drift, the licensee was able to confirm that drift over three months is not a significant' factor.

The justification for extending allowed outage times and surveillance test intervals for f unctional units.6h (emergency feedwater suction tr esfer on low pressure) and 8a (automatic switchover to containment sump on RWJ level Lnw-Low) was provided in an attachment to the licensee's submittal. A:

evaluation of their justification is presented below:

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e e' Emergency feedwater Suction Transfer The design configuration of the instrument was reviewed.

The instrument consists of four channels providing signals via input relays to each train of the solid stace protection system.

Each channel consists of a densor, a transmitter, a channel test switch, a loop power supply, a comparator, and a comparator trip switch.

This design is identical to that of the pressurizer pressure circuitry.

Since the pressurizer pressure circuitry was modeled by-Westinghouse in the preparation of WCAP-10271, and since testing procedures used at Sunner Station are identical to or more conservative than those modeled by Westinghouse, the unavailability due to the surveillance test intervals and allowed outage times proposed for the pressurizer pressure instrument are directly applicable to emergency feedwater suction transfer, The Westinghouse methodology yielded a 12 percent increase in unavailability for this signal.

Since the range in unavailability for functior al Units evaluated by Westinghouse was from 12 percent to 35 percent, the staff has concluded that the proposed extensions of surveillance test intervals and allowed outage times are consistent with those evaluated in the SERs on WCAP-10271 and are, therefore, acceptable.

RWST-Switchover The design configuration of the instrument was reviewed. Although the instrument-was not modeled in the preparation of WCAP-10271, an identical instrument, specifically the steam generator level instrument, was modeled.

An argument analogous to that for the emergency 'feedwater suction transfer has shown that the increase in unavailability is again on the order of 12 percent.

Thus the proposed changes are consistent with those evaluated in the SERs on WCAP-10271 and are, therefore, acceptable, 2.1

SUMMARY

- The changes proposed by this amendment request may be placed in three categories:

1) those that are administrative in nature, 2) those that are covered under one of the generic SERs on WCAP-10271, and 3) those that require a plant-specific analysis. The changes that are administrative in nature have

.no safety significance and are therefore considered acceptable. Of the remaining changes, all but those to f unctional Units 6h and 8a have been determ:ned to be enveloped by the SERs of February 21, 1985, February

?,-1989, and the SSER of April 130, 1990; therefore, these-changes are acceptat The proposed changes to the surveillance requirements on Functional Units ch and 8a have been evaluated by the staff and are considered _ acceptable.

The proposed i-amendment as a whole is therefore considered acceptable.

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3.0 ENVIRONMENTAL CONSIDERATION

This amendment changes requirements in the installatior or use of a facility component located within the restricted area, as defined in 10 CFR Part 20, and changes the surveillance requirements.

The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released off-site, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previoucly issued a proposed finding that this amendment involves no significant hazards consideration, and there has been no public comment on such finding. Accordingly, this amendment meets the eligibility criteria for criegorical exc'usion set forth in 10 CFR 51.22(c)(9).

Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.

4.0 CONCLUSION

The Commission' made a ; roposed ietermination that this amendment involves no significant hazards consideration, which was published in the FEDERAL REGISTER (56 FR 2555) on January 23, 1991, and consulted with the State of South Carolina.

No public comments or requests for hearing were received, and the State of South Carolina did not have comments.

The staff has concluded, based on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with-the Commission's regulations, and (3) the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the

public, tincipalContributor:

G. Wunder Dated: June 18, 1991 1

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