ML20081E802

Proposed Tech Specs Adding Footnote to 3/4.6.1.7 That Excludes Drywell Purge Supply Valve 2CPS*AOV106 from Leak Rate Requirements of 4.6.1.7.2 & Action Statement 'B' of LCO 3.6.1.7

ML20081E802
Person / Time
Site:	Nine Mile Point
Issue date:	04/29/1991
From:	NIAGARA MOHAWK POWER CORP.
To:
Shared Package
ML20081E780	List: ML20081E779 ML20081E791 ML20081E802
References
NUDOCS 9105020158
Download: ML20081E802 (11)

Text

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i ATTACEMENT A Page 1 of 3 NIARRA NCEAWK POWER J:0RPORATION LICENSE NO. NPF-49 DOCKET No. 50-410 Proposed Chances to the Technical specificati.QAR Replace pages 3/4 6-13 and 6-14 with the revised pages. The proposed revisions are indicated by markings in t.ae margin.

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9105020158 920429 FDR ADOCK 0D000410 PDR P

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E911TAlllEENT MATEMS EA} MARY CQNTAINMENT

'fRIliARY COliTAINMENT PURGE SYSTEM

j. [IMITING CONDITIONS FOR OPERATION 3.6.1.7 The drywell and suppression chamber 12-inch and 14-inch

. purge supply and exhaust isolation valves shall be OPERABLE ands

a. The 12-inch (2 CPS *AOV105, 2 CPS *AOV107, 2 CPS *AOV109, 2 CPS *AOV111) and 14-inch (2 CPS *AOV104, 2 CPS *AOV106, 2 CPS *AOV108, 2 CPS *AOV110) valves in the purge system supply and exhaust lines may be open for up to 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> per 365 days for VENTING or PURGING.*

b. Purge system valves 2 CPS *AOV105 (12-inch), 2 CPS *AOV107 (12-inch), 2 CPS *AOV109 (12-inch), and 2 CPS *AOV110 (14-inch) shall be blocked to limit the opening to 70*. Purge system valve 2 CPS *AOV111 (12-inch) shall be blocked to limit the opening to 60*.

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APPLICABILITY: OPERATIONAL CONDITIONS 1, 2, AND 3.

ACTION:

a. With the drywell and suppression chamber purge supply and/or exhaust isolation valve (s) inoperable, or open for more than 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> per 365 days for other than pressure contro1*,

close the opsn valve (s); otherwise isolate the penetration (s) within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 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 /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, b, With a drywell and suppression chamber purge supply and/or exhaust isolation valve (s) with resilient material seals having a measured leakage rate exceeding the limit of Surveillance Requirement 4.6.1.7.2, restore the inoperable valve (s) to OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 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 /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.**

• The 90-hour limit shall not apply to the use of valves 2 CPS *AOV108 (14-inch) and 2 CPS *AOV110 (14-inch), or 2 CPS *AOV109 (12-inch) and 2 CPS *AOV111 (12-inch), for primary containment pressure control, provided 2GTS*AOV101 is closed, and its 2-inch bypass line is the only flow path to the standby gas treatment system.

• • Action statement "b" does not apply to 2 CPS *AOV106 from April 24, 1991 until the next plant shutdown but not later than September 30, 1991 provided that 2 CPS *AOV104 is closed

, and deactivated and 2 CPS-V6 is locked closed.

NINE MILE POINT UNIT 2 3/4 6-13

CONTAINMENT SYSTEMS PRIMAEl_ CONTAINMENT PRIMARY CORTAINtLERT_fflQE SYSEM SURVEILLANCE R,EQUIREMENTS j 4.6.1.7.1 At least once per refueling outage each drywell and suppression chamber purge supply and exhaust isolation valve of 3

Specification 3.6.1.7.b shall be verified to be blocked to limit the opening to 70' or 60', as applicable:

4.6.1.7.2 At least once per 92 days each 12- and 14-inch drywell and suppression chamber purge supply and exhaust isolation valve with resilient material seals shall be demonstrated OPERABLE by verifying that the measured leakage rate is less than or equal to 4.38 scf per hour per 14-inch valve and 3.75 scf per hout per 12-inch valve when pressurized to Pa, 39.'E psig. Those purge supply and exhaust isolation valves 42sted on Table 3.6.1.2-1 shall be pressurized to 40.0 psig.* l

• Surveillance requirement 4.6.1.7.2 does not apply to 2 CPS *AOV106 from April 24, 1991 until the next plant shutdown but not later than September 30, 1991 provided that 2 CPS *AOV104 is closed and deactivated and 2 CPS-V6 is locked closed.

NINE MILE POINT - UNIT 2 3/4 6-14

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ATTACHMENT B l

, NIAGARA MOHAWK POWER CORPORATION LICENSE No. NPF-69 )

DOCKET No. 50-410 l

SUPPORTING INFORMATION AND NO SIGNIFICANT HAZARDS CONSIDERATION Discussion Containment Purge System (CPS) inboard isolation valve 2 CPS *AOV106 does not meet the leakage rate requirements contained in Technical Specification Surveillance Requirement 4.6.1.7.2.

This renders the valve inoperable. However, 2 CPS *A0V106 has been closed.

Compensatory actions have been taken. The other isolation valve on the same containment purge line, containment purge outboard isolation valve 2 CPS *A0V104, has been satisfactorily leak tested to 0.023 scfh. This test was conducted by placing a vacuum between 2 CPS *A0V104 and the upstream manual isolation valve 2 CPS-v6 and pressurizing the downstream side of 2 CPS *A0V104 to 40 psig. 2 CPS *AOV104 has subsequently been verified closed and deactivated in accordance with Technical Specification 3.6.3. In addition, valve 2 CPS-V6 has been locked shut. Containment Purge System (CPS) valves 2 CPS *A0V104, 2 CPS *A0V106, and 2 CPS-V6 are marked up in the closed position, that is, the position in which the leak test was conducted. The markup ensures that these valves are not inadvertently opened.

As noted, 2 CPS *AOV104 ha6 been leak tested to 0.023 scfh. With 2 CPS *AOV104 and 2 CPS-V6 shut, it is reasonable to assume that the containment leakage through this pathway will be limited to this amount since 2 CPS *A0V104 is the outboard isolation valve for the penetration. The subject Containment Purge System line is a potential secondary containment bypass leakage path. The bypass leakage analysis for these valves assumed that the loakage rate would be at the Technical Specification surveillance limit (4.38 scfh) for each valve. With outboard isolation valve 2 CPS *A0V104 leakage well below the limit and the manual valve closed, the total bypass leakage of the drywell purge inlet line will be less than assumed in the design basis assumptions in the radiological evaluation-of the DBA LOCA as described in Updated Safety Analysis Report (USAR) chapter 15. Therefore the radiological conclusions reached in the USAR will remain valid.

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Page 2 of 6 rail.ur'e of the CPS is not an initiating event for any accident

,previously analyzed in the USAR. The proposed CPS configuration for the drywell purge line identified above will not impact the accident analyses in the USAR. The safety function of the automatic CPS isolation valves 2 CPS *AOV104 and 2 CPS *AOV106 is to shut in the event of an isolation signal to prevent containment leakage via the associated CPS drywell purge penetration. By maintaining these valves shut, an automatic action is not required to effect this safety function. Moreover, given this configuration, a single active failure will not prevent the isolation of the associated CPS penetration. ,

The CPS is classified nonessential and is not required for safe shutdown. The system can, however, be used as a backup to the DBA Hydrogen P,ecombiner system for combustible gas control.

Given a LOCA and a concurrent failure of both category 1 recombiners, three other containment purge supply lines will be available.

The 2 CPS *AOV106 valve is leak rate tested to meet Appendix J requirementn. The initial and highest quantified leakage of 2CPa*AOV106 is 166.990-sef per hour. In accordance with NMP2 T.S. LCO 3.6.1.2.b, the combined leakage rate for all penetrations and all valves listed in Table 3.6.3-1, except for main steam line isolation valves, subject to Type B and C testing when pressurized to Pa of 39.75 psig must be less than or equal to 0.60 La. Valve 2 CPS *AOV106 is listed on T.S. Table 3.6.3-1.

The value for 0.60 La is 494.640 scf per hour. With an initial and highest quantified leakage of 166.990 for 2 CPS *AOV106, the combined leakage for Type B and C testing is currently equal to 314.419 scf per hour. Therefore, it can be concluded that operation with 2 CPS *AOV106 leakage in excess of T.S. criterion specified in T.S. surveillance 4.6.1.7.2 does not lead to non-compliance with LCO 3.6.1.2.b.

The primary containment nitrogen inerting system establishes and maintains an oxygen deficient atmosphere in the primary containment during normal operation. In addition, the primary Containment Purge System is provided to aid in the post acciient cleanup operation. The 2 CPS *AOV106 valve is located on the nitrogen supply line for the drywell. Since an alternate pathway is available within the primary containment Purge System to supply nitrogen to the drywell, the closing of the redundant primary containment isolation valve for 2 CPS *AOV106 does not adversely affect the ability of the primary containment nitrogea inerting system to maintain an oxygen deficient atmosphere nor does it adversely affect the ability of the Containment Purge System to support post accident cleanup operations.

The last time this surveillance was performed on this valve during January, 1991, the initial leakage was unsatisfactory.

However, the leakage went down markedly after flushing the valve internals with air ar.d eventually the leakage was lowered to-within the specification limit following a second purge.

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, Testing for all remaining drywell and suppression chamber purge supply and exhaust isolation valves with resilient material seats was completed by 5:00 a.m. on April 25, 1991.

The valves, their corresponding size, leakage and acceptance criteria are as follows.

Nominal Size of T.S.

Valve Diameter Test Results Acceptance Criteria Yalve Nat (Inches) (sef oer hour) (sef ner hgyr) 2 CPS *AOV104 14 0.023 4.38 2 CPS *AOV105 12 1.424 3.75 2 CPS *AOV107 12 1.603 3.75 2 CPS *AOV100 14 1.874 4.38 2 CPS *AOV109 12 0.818 3.75 2 CPS *AOV110 14 1.291 4.38 2 CPS *AOV111 12 0.785 3.75 If any of these above seven valves fall to pass the acceptance criteria of T.S. Surveillance 4.6.1.7.2 leakage testing, the plant will comply with action statement "b" for LCO 3.6.1.7.

As indicated above, testing was performed on 2 CPS *AOV104, which is the redundant primary containment isolation valve for the affected penetration. After valve 2 CPS *AOV104 was T.S.

Surveillance 4.6.1.7.2 tested, it was left in its as tested closed condition, deactivated, and tagged to prevent inadvertent re-energization. In addition, the inboard valve 2 CPS *AOV106 wac also left in a closed position. A locally operated valve, 2 CPS-V6, which is the first valve upstream of 2 CPS *AOV104, was closed and locked.

After completion of leakage testing, the three valves, 2 CPS *AOV104, 2 CPS *AOV106 and 2 CPS-V6, will not be operated during the period of time for which continued operation of NMP2 requires reliance on the proposed emergency T.S. change.

NMPC believes that increasing the test frequency of T.S.

Surveillance 4.6.1.7.2 for the above seven valves is not appropriate. The basis for this conclusion ist (1) the above test results for the seven valves indicates that the remaining valves are performing their leakage barrier function significantly better than that required by T.S.

Surveillance 4.6.1.7.2.

Page 4 of 6 (2) a review of the testing history, since 1986, of all eight valves indicated that there are no indications of failure trends and that the valves have & high rate of success when tested in accordance with T.S. 4.6.1.7.2.

(3) when the above two items are considered together, it can be concluded that the failure of the Technicel Specification surveillance test for 2 CPS *AOV106 is not indicative of resilient seal degredation on the remaining seven valves.

As previously indicated, all remaining seven drywell and suppression chamber purge supply and exhaust isolation valves with resilient mhterial seats have been tested in accordance with T.S. surveillance 4.6.1.7.2.

The successful completion of this testing demonstrates that the failure of the surveillance test for 2 CPS *AOV106 is not indicative of a common problem associated with the other Containment Purge System valves. A review of the testing history of all eight valves indicated that there are no indications of failure trends and that the valves have a high rate of success when tested in accordance with T.S. surveillance 4.6.1.7.2. Based upon the recent test results of the remaining seven valves with resilient seals and a teview of previous results, it can be concluded that the failure of the surveillance test for 2 CPS *AOV106 is not indicative of early resilient materials seal degradation on the remaining seven valves a.id is evidence that the margin of safety has not been reduced. -

Containment isolation valve 2 CPS *AOV106 will be restored to operable ~

status prior to restart from the next unit outage which will begin no later than September 30, 1991.

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. l Page 5 of 6 Nine Mile Point can be operated with the incorporation of the changes in ,

the proposed amendment. 10CFR50.91 requires that at the time a licensee l requests an amendment, it must provide the Commission its analysis using l tho standards in 10CFR50.92 concerning the issue of no significant hazards i consideration. Therefore, in accordance with 10CFR50.91, the following enalysis.has been performed: 1 Th@ operation of Nine Mile Point Unit 2, in accordance with the proposed ccandment, will not involve a significant increase in the probability or consequences of an accident previously evaluated.

Tho proposed changes will not involve a significant increase in the probability or consequences of an accident previously evaluated. The follure of CPS components is not an initiating event for any accident analyses previously evaluated in the USAR. The proposed CPS configuration will not impact any of the USAR accident analyses. The resultant leakage through the affected containment penetration based on test measurements cnd the combined leak rate .s less than that assumed by radiological ovaluations of design bases events. Therefore, the radiological conclusions in the USAR will remain valid. Moreover, the CPS is classified nonessential wita the exception of the primary containment ponetration and its associated isolation valves and is not required for cafe shutdewn. In the unlikely event the CPS is needed for combustible gas control, three separate CPS purge lines will be readily available.

Tha operation of Nine Mile Point Unit 2, in accordance with the proposed

'ccandment, will not create the possibility of a new or different kind of occident from any previously evaluated.

The proposed change will not create the possibility of a new or different accident from any previously evaluated. No new operational modes will result from the proposed changes. The CPS isolation valves (2 CPS *AOV104 and 2 CPS *AOV106) vill be maintained shut as required in the event an isolation is required. A single active failure will not affect the position of these valves. The remaining CPS isolation valves test results and a review of previous test results since 1986 demonstrate that_ generic rosilient seal deterioration is not indicated such that. a different type of accident is not created.

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-Thaloperation-of.Nine Mile Point Unit 2, in accordance with the proposed; -

icosndment, wil. r-t involve a significant reduction in a margin-of safety.

The proposed amendment will not-involve a significant reduction in the -

margin of-safety. - Given the historical' data for this surveillance on 2 CPS *AOV106 and other CPS isolation valves, seal degradation and subsequent gross failbre'is not' indicated. Each remaining CPS isolation -

valve has been leak tested with results that are well below the surveillance limit. Furthermore, the time period that'the plant is operating-under this proposed change will be limited to the next shutdown

-or-September,30, 1991 whichever is earlier. Containment isolation valve

=2 CPS *AOV106 will'be restored to operable status prior to restart of-the

.unitJfrom;the outage.

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. ATTACHMENT C Page 1 of 1 NIAGARA MOHAWK POWER CORPORATION LICENSE NO. NPF-69 DOCKET NO. 50-410 ,

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Exclanation of why Emergency Occurred and l WhY It Could Not Be Avoided On. April _23, 1991, surveillance testing in accordance with Technical  !

Specification surveillance 4.6.1.7.2 was performed on drywell purge line l inboard isolation valve 2 CPS *AOV106. Tha leakage through the valve was cbove the surveillance limit. Despite attempts at restoring the valve to operable status by flushing the valve internals with air and nitrogen to remove any particles, the leakage could not be reduced below the limit.

Consequently, a normal plant shutdown was specified by action statement "b" of LCO 3.6.1.7. -After discussion with the NRC Staff, a Temporary Waiver of Compliance was granted on Areil 24, 1991. On April 25, 1991,.

Niagara Mohawk submitted a letter (NW1 L1295) documenting its request for tha temporary waiver of compliance. Tous Niagara Mohawk has made timely lcpplication for this emergency amendment.

In the previous surveillance test of this valve in January.1991, a similar-situation developed. Action was taken to flush the valve internals with

-cir. This action was successful in that leakage from 2 CPS *AOV106 was subsequently lowered below the surveillance acceptance criterion. No physical modification or valve seat _ rework was required to pass the Technical Specification Surveillance. None of the other valves experienced this problem at that time. Thus Niagara Mohawk could not anticipate'or avoid the situation leading up to this request.

Niagara Mohawk requests that.this application for amendment be considered-an emergency situation in order for Nine Mile Point Unit 2_to continue oporation in accordance with 10CFR50.91 and that prior notice for opportunity for a hearing be waived.

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Page 1 of 1 ATTACHMENT D NIAGARA MOHAWK POWER CORPORATION LICENSE NPF-69 DOCKET NO. 50-410 Environmental Considerations This amendment involves a change to a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10CFR Part 20. The change is to surveillance requirement 4.6.1.7.2 and action statement "b" of LCO 3.6.1.7 of the Technical Specification for NMP2. The amendment will allow continued operation of NMP2 with 2 CPS *AOV106 leakage in excess of the criterion set forth in 4.6.1.7.2 of the Technical Specification. Compensatory actions include closing and deactivating 2 CPS *AOV104, the redundant primary containment outboard isolation valve for the affected penetration, and locking closed 2 CPS-v6, which is upstream of 2 CPS *AOV104. Leakage testing was performed which demonstrates 2 CPS *AOV104 satisfies the criterion set forth in 4.6.1.7.2. In addition, 2 CPS *AOV106 is also closed. After completion of leakage testing, the three valves, 2 CPS *AOv104, 2 CPS *AOv106 ond 2 CPS-V6, will not be operated during the period of time for which continued operation of NMP2 requires reliance on the proposed emergency T.S. change.

Niagara Mohawk hhs 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 offsite and that there is no significant increase in individual or cumulative occupational radiation exposure.

Niagara Mohawk has determined that this amendment involves no significant hazards consideration. Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10CFR 51.22(c)(9).

Pursuant to 10CFR 51.22(b), no environmental impact statement nor environmental assessment need be prepared in connection with the issuance of this amendment.