ML20067C897

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Proposed Tech Specs 3.6.1.2 & 3/4.6.1.2 Re one-time Extension of Surveillance Requirements for Containment Sys
ML20067C897
Person / Time
Site: Summer South Carolina Electric & Gas Company icon.png
Issue date: 02/04/1991
From:
SOUTH CAROLINA ELECTRIC & GAS CO.
To:
Shared Package
ML20067C891 List:
References
NUDOCS 9102120242
Download: ML20067C897 (9)
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ATTACHMENT 1 MARKED-UP TECHNICAL SPECIFICATION PAGES P_a,jg Specification Chanqe Description 3/4 6-2 3.6.1.2 One Time Extension to Surveillance Requirements B 3/4 6-1 3/4 6.1.2 One Time Extension to Surveillance Requirements e

1 9102120242 910'204 P,DR j ADOCK0500t.~g5

CONTAINMENT SYSTEMS CONTAINMENT LEAKAGE LIMITING CONDITION FOR OPERATION 3.6.1.2 Containment leakage rates shall be limited to:

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a. An overall integrated leakage rate of:
1. Less than or equal to L 0.20 percent by weight of the contain-ment air per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> at,P,, 47.1 psig, or
2. Less than or equal to L 0 ment air per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> ak,a r.10 percent educed by weight pressure of P of the contain-

. 23.6 psig, t

b. for all penetrations and A combined valves subject leakage to Type B rate and Coftests, lesswhen than 0.60 Llressurized ,.

to P APPLICABILITY: MODES 1, 2, 3 and 4.

ACTION: .

1 With either (a) the measured overall integrated containment leakage rate or 0.75 L , as applicable, or (b) with the measured combined exceeding leakage rate0.75 for L,all penetrktions and valves subject to Types 8 and C tests restore the overall integrated leakage rate to less than or exceeding equal to 0.750.60L L,o,r less than or equal to 0.75 L , as applicable, and the combined leakagl rate for all penetrations subjekt to Type B and C tests to less than 0.60 L, prior to increasing the Reat. tor Coolant System temperature above 200*F.

SURVEILLANCE REQUIREMENTS 4.6.1.2 The containment leakage rates shall be demonstrated at the following test schedule and shall be determined in conformance with the criteria spect-fied in Appendix J of 10 CFR 50 using the methods and provisions of ANSI N45.4-1972:

a. Three Type A tests (Overall Integrated Containment Leakage Rate) shall be conducted at 40 2 10 month intervalsiduring shutdown at either P, (47.1 psig) or at P1 (23.6 psig) during each 10 year

, service period. The third test of each set shall be conducted

! during the shutdown for the 10 year plant inservice inspection.

-)e A one time extension of the test interval is allowed for the third Type A test within the first 10-year service period, provided unit shutdown occurs no later than June 1,1993 and performance of the Type A test occurs prior to unit restart following RF7.

I i SUM ER - UNIT 1 3/4 6-2 l

3/4.6 i.ONTAINMENT SYSTEMS BASES 3/4.6.1 PRIMARY CONTAINMENT -

3/4.6.1.1 CONTAINMENT INTEGRITY Primary CONTAINMENT INTEGRITY (1sures that the release of radioactive materials from the containment atmosphere will be restricted to those leakage paths and associated leak rates assumed in the accident analyses. This restric-

tion, in conjunction with the leakage rate limitation, will limit the site boundary radiation doses to within the limits of 10 CFR 100 during accident conditions. l l

1 3/4.6.1.2 CONTAINMENT LEAKAGE l The limitations on containment leakage rates (including those used in i demonstrating a 30 day water seal) ensure that the total containment leakage l

. volume will not exceed the value assumed in the accident analyses at the peak '

accident pressure, P . As an added conservatism, the measured overall inte- 1

- grated leakage rate is further limited to less than or equal to 0.75 L or 1 0.75 L asapplicable,duringperformanceoftheperiodictesttoacc8untfor 1

, possibie,degradationofthecontainmentleakagebarriersbetweenleakagetests.

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The surveillance testing for measuring leakage rates are consistent with the requirements of Appendix "J" of 10 CFR 50.#

-3/4.6.1.3 REACTOR BUILDING AIR-LOCKS The limitations on closure and leak rate for the reactor building air locks are reauired to meet the restrictions on CONTAINMENT INTEGRITY and containment leak rate. Surveillance testing of the air lock seals provide assurance that the overall air lock leakage will not become excessive due to seal damage during the interval

  • het een air lock leakage tests.

--ye A one time extension of the test interval is allowed for the third Type A test within the first 10-year service period, as required by Surveillance Requirement 4;6.1.2.a and by section III.D.1.(a) of Appendix J. of 10CFR50, provided unit shutdown occurs no later than June 1,1993 and performance of the Type A test occurs prior to unit restart following RF7.

SUMMER - UNIT 1 B 3/4 6-1 Amendment No. 47

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ATTACllMENT 2 DESCRIPTION OF AMENDMENT REQUEST AND SAFETY EVALUATION l

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i Attachment 2 to Document Control Desk Letter TSP 910001 Page 1 of 2  ;

O PROPOSED TECHNICAL SPECIFICATION CHANGE AND SAFETY EVALUATION FOR THE VIRGIL C. SUMMER NUCLEAR STATION DESCRIPTION OF AMENDMENT REQUEST SCE&G proposes to modify the VCSNS Technical Specifications to request a one-time extension of the 40 +/- 10 month, type A, test schedule as described by conteinment system sur'.eillance requirement (SR) 4.6.1.2.a. The proposed change would permit the third containment integrated leak rate test (ILP,T) to be performed during refueling outage 7 (RF7). The current SR 4.6.1.2.a states:

"Three Type A tests (0verall Integrated Containment Leakage Rate) siall be conducted at 40 +/- 10 month intervals during shutdown at Pa (47.1 psig) or Pt (23.6 psig) during each 10-year service period. The third tert of each set shall be conducted during the shutdown for the 10-year plant inservice inspection."

SCE&G proposes to add a footnote to allow a one-time utension of the current test interval. The footnote reads as follows: "A one-time extension of the test interval is allowed for the third Type A test within the first 10-year service period provided unit shutdown occurs no later than June 1, 1993, and performance of the Type A test occurs prior to unit restart following RF7."

REASON FOR CHANGE in accordance with the 40 +/- 10 month test interval, VCSNS would be required l to perform its third periodic Type A test on or before February 9, 1993 (50 l months). Application of the 40 +/- 10 month rule would require SCE&G to perform a Type A test during RF6 (presently scheduled for fall of 1991) and then repeat it during RF7 (presently scheduled for spring of 1993) since the third Type A test (ILR') is required to be performed during the shutdown for the 10-year plant inse vice inspection.

The proposed modification to the Type A test schedule is a one-time exemption to the required test interval. The proposed extension of tne 40 +/- 10 month test interval would enable VCSNS to complete its seventh fuel cycle without having back-to-back refueling outages requiring Type A tests. Considering that all plant maintenance activities and modifications are implemented l under plant administrative control combined with the fact that no operational i transients have occurred that would have adversely affected containment l integrity, SCE&G finds no reason to suspect degradation in the containment since the last Type A test was completed.

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Attachment 2 to Document Control Desk Letter TSP 910001 Page 2 of 2 SAFETY EVALVATION:

The results of the pre /ious two Type A test have shown the overall leakage from the containment building has remained at very low levels, Based on the test data (test data has 95% upper confidence level) from the previous two Type A tests. 0.094 percent per day-(Type A test performed in October 1984) and 0.1057 percent per day (Type A test performed in December 1988), tne overall leak rate has consistently remained well below' acceptable levels (acceptance criteria for VCSNS Type A tests is 0.15 percent per day). Given these historical margins, combined with the fact that all plant ma'intenance activities and modifications are implemented under plant administrative control and the fact that the containment has not been subjected to any operational trans'ients adversely affecting the containment integrity, SCE&G considers the proposed change ",be justified.

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ATTACHMENT 3 DESCRIPTION OF AMENDMENT REQUEST ARD WO SIGNIFICANT liAZARDS CONSIDERA1'JH n.

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. Attachment 3 to Document Control Oesk letter TSP 910001 Page 1 of 2 DESCRIPTION OF AMENOMENT REQtlEST SCE&G proposes to modify the VCSNS Technical Specifications to request a one-time extension of the 40 +/- 10 month, type A, test schedule as described by containment system surveillance requirement (SR) 4.6.1.2.a. The proposed change would permit the third containment integrated leak rate test (ILRT) to be performed during refueling outage 7 (RF7). The current SR 4.6.1.2.a states:

"Three Type A tests (Overall Integrated Containment Leakage Rate) shall be conducted at 40 +/- 10 month intervals during shutdown at Pa (47.1 psig) or Pt (23.6 psig) during each 10-year service period. The third test of each set shall be conducted during the shutdown for the 10-year plar.t inservice inspection."

SCE&G proposes to add a footnote to allow a one-time extension of the current test interval. The footnote reads as follows: "A one-time extension of the test interval is ?llowed for the third Type A test within the first 10-year service period provided unit shutdown 0; curs no later than June 1, 1993, and performance of the Type A test occurs prior to unit restart following the RF7."

REASON FOR CHANGE in accordance with the 40 +/- 10 month test interval. VCSNS would be required to perfc"m its third periodic Type A test on or before February 9, 1993. (50 months). Application of the 40 +/- 10 month rule would require SCE&G to perform a Type A test during RF6 (presently scheduled for fall of 1991) and then repeat it during the RF7 refueling outage (presently scheduled for spring of 1993) since the third Type A test (ILRT) is required to be performed during the shutdown for the 10-year plant inservice inspection.

The proposed modification to the Type A test schedule is a one-time exemption to the required test interval. The proposed extension of the 40 +/- 10 month test interval would enable VCSNS to complete its seventh fuel cycle without having back-to-back refueling outages requiring Type A tests. Considering that all plant maintenance activities and modifications are implemented under plant administrative control combined with the fact that no operational transients have occurred that would have adversely affected containment integrity, SCE&G finds no reason to suspect degradation in the containment since the last Type A test was completed.

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Attachment 3 to Document Control Desk tetter TSP 910001 Page 2 of 2 BASIS FOR PROPOSED NO SIGN!fICAN! HAZARDS CONSIDERATION:

SCELG has evaluatad the proposed Technical Specification change and determined that ,t does not represent a significant hazards consioeration 1 base on criteria established in 10CFR50.92(c). Operation of VCSNS with the p*nposed amendment will not:

(1) Involv. significant increase in the probability or Consequences of an acciden1, previously evaluated. The proposed change is a one-time extension of the 40 +/- 10 month Type A test interval as contaivo in Surveillance Requirement 4.6.1.2.a. The purpose of the Type A test u to ensure that leakage from the primary containment through systems and cc:npon2nts penetrating primary containment does not exceed allowable leakageratevaluesspecifiedintheTechSpecs(VCSNSlimitis0.75La which equates to 0.15 percent per day). Testing pursuant to SR 4.6.1.2.a was last satisfactorily completed on 12/88 at which time the actual measured Icak rate was well below the required value of the plant's Technical Specifications. SCE&G therefore concludes that extending the surveillance interval would not cause 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 previously analyzed. No new accident scenarios are created by the proposed change because the one-time extension affects only the test frequency and does not affect the physical containment structure, the penetrations or the facility. Previous Type A test results have shov the leak rates have remained well below the 0.75 La (0.15 percent pei day) limit. Because the leakage limit has not been comprc.nised, the requested extension of the test intervel will in no way create the possiH 11ty of a new or different kind of accident from any previously analyzed.

(3) Involve a significant reduction in the margin of safety. The test data (test data has 95% upper confidence level) from the previous two Type A tests, 0.094 percent per day (Type A test performed in October 1984 and0.1057percentperday(TypeAtestperformedinDecember1988)),

the overall leak rate has consistently remained well below acceptable levels (acceptance criteria for VCSNS Type A tests is 0.15 percent per day). Baser, on the previous measured leakap rates combired with the design modification and process control administrative procedures, the one-tine extension of the 40 +/- 10 month. Type A, test interval would not involve a significant reduction in the margin of safety.

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