ML20036A450

Proposed TS 4.6.1.2.f Re Operability Requirements for Purge Supply & Exhaust Isolation Valves & 3.6.1.7 Re LCO for 8 Inch Containment Purge Supply & Exhaust Isolation Valve

ML20036A450
Person / Time
Site:	Seabrook
Issue date:	05/07/1993
From:	NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO)
To:
Shared Package
ML20036A448	List: ML20036A447 ML20036A449 ML20036A450 ML20036A451
References
NUDOCS 9305110229
Download: ML20036A450 (19)

Text

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Markup of Proposed Chances See attached markup of proposed changes to Technical Specifications.

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i 9305110229 930507 PDR ADOCK 05000443 P-PDR

CONTAINMENT SYSTEMS l

PRIMARY CONTAINMENT CONTAINMENT LEAKAGE i

SURVEILLANCE REOUIREMENTS 4.6.1.2 (Continued) d.

Type B and C tests shall be conducted with gas at a pressure not less than P,, 49.6 psig, at intervals no greater than 74 months except for tests involving:

1)

Air locks, and 2)

Purge supply and exhaust isolation valves with resilient material seals.

e.

The combined bypass leakage rate shall be determined to be less than or equal to 0.60 L, by applicable Type B and C tests at least once per 24 months.

f.

Purge supply and exhaust isolation valves with resilent material seals shall be tested and demonstrated OPERABLE by the requirements of spect -

fication 4.6.1.7,((gr 4.6.1.7.3, as applicable g; g.

Air locks shall be tested and demonstrated OPERABLE by the requirements of Specification 4.6.1.3; and h.

The provisions of Specifications 4.0.2 are not applica"le.

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SEABROOK - UNIT 1 3/4 6-4 i

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CONTAINMENT. SYSTEMS PRIMARY CONTAINMENT CONTAINMENT VENTILATION SYSTEM LIMITING CONDITION FOR OPERATION i

EachAco{3-inch

3. 5.1. 7 ntainment purge supply and exhaust isolation valve shall be i

OPERABLE and Each 36 inch containment shutdown purge supply and exhaust isolatio.

a.

I valve sh 11 be closed and locked closed, and i

The8-inhcontainmentpurgesupplyandexhaustisolationvalve(s)]

b.

hall bg)Lsealed closec except wnen open for purge system operation 7

for pressure control; for ALARA, respirable, and air quality consider-l ations to facilitate personnel entry; and for surveillance tests l

that require the valve (s) to be open.

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

ACTION:

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With a 36-inch containment purge supply or exhaust isolation valve open or not locked closed, close and lock closed that valve 1

or 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 />, otherwise be in' at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in LOLD SHUTDOWN' within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

f With one or more of the 8-inch containment purge supply or exhaust a~

isolation vatve pen for reasons other than given in Specifica-tion 3.6.1.7.b a ove, close the open 8-inch valve (s) or 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 />, otherwise be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

f.

With one or more containment purge supply or exhaust isolation b

valves having a measuredMeakage rate]n excess of the limits of SpecificatiordF4.6.1.7.2 ob 4.6.1.7.J, restore the inoperaole valve (s) to OPERABLE status or isoTate the affected penetration (s) so that the measured leakage rate does not exceed the limits of SpecificatioF M 6.1.7.2 % 4.6.1.7.

within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and close the purge supply if the affected penetra n is the exhaust penetration, otherwise be in at least HOT STANDBY ithin the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

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SEABROOK - UNIT 1 3/4 6-12 f

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CONTAINMENT SYSTEMS r

PRIMARY CONTAINMENT CONTAINMENT VENTILATION SYSTEM SURVEILLANCE REQUIREMENTS i

4.6.1.7.1 Each 36-inch containment purge supply and exhaust isolation valve shall be verified to be locked closed at least once per 31 days.*

4.6.1.7.2 At least once per 6 months on a STAGGERED TEST BASIS, the inboard and outboard isolation valves with resilient material seals in each sealed closed 36-inch containment purge supply and exhaust penetration shall be demonstrated OPERABLE by verifying that the measured leakage rate is less than or equal to 0.05 L when pressurized to P

• a a-4.6.1.7.J.1At least once per 92 days each 8-inch containment 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 0.01 L when pressurized to P,.

a 4.6.1.7.MEach8-inchcontainmentpurgesupplyandexhaustisolationvalve shall be verifi d to be sealed closed or open in accordance with Specifi-cation 3.6.1.7.b at least once per 31 days.

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• Containment entry and verification that the inside 36-inch containment purge and exhaust isolation valves are locked closed is not required until a containment entry is made if no containment entry has been made since the last time the inside 36-inch containment purge and exhaust isolation valves were verified closed.

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SEABROOK - UNIT 1 3/4 6-13 y

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i CONTAINMENT SYSTEMS BASES 3/4.6.1 PRIMARY CONTAINMENT (Continued) 3/4.6.1.5 AIR TEMPERATURE The limitation in containment average air temperature ensures that the containment average air temperature does not exceed the initial temperature condition assumed in the overall safety analysis for a steam line break acci-dent. Measurements shall be made at all listed locations, whether by fixed or portable instruments, prior to determining the average air temperature.

3/4.6.1.6 CONTAINMENT VESSEL STRUCTURAL INTEGRITY This limitation ensures that the structural integrity of the containment steel vessel will be maintained comparable to the original design standards for the life of the facility.

Structural integrity is required to ensure that the vessel will withstand the maximum pressure of 52 psig in the event of a LOCA.

A visual inspection in conjunction with Type A leakage tests is sufficient to demonstrate this capability.

3/4.6.1.7 CONTAINMENT VENTILATION SYSTEM The 36-inch containment purge supply and exhaust isolation valves are required to be sealed closed during plant operation since these valves have not been demonstrated capable of closing during a LOCA or steam line break accident.

Maintaining these valves closed during plant operations ensures that excessive p*5EgT quantities of radioactive materials will not be released via the Contai Purge System.

To provide assurance that these containment valves cannot be b.. 7 inadvertently openeMthe valves are sealed closed in cictordance with Standard'[/

Review Plan dection 6.2.4 which includes mechanical devices to seal or lock the valve closed, or prevents power from being supplied to the valve opera t

The use of the containment purge lines is restricted to the 8-inch purge

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supply and exhaust isolation valves since, unlike the 36-inch valves, the 8-inch valves are capable of closing during a LOCA or steam line break accident.

Thcre-fore, the SITE BOUNDARY dose. guideline values of 10 CFR Part 100 would not be exceeded in the event of an accident during contain, ment PURGING operation.

The total time the containment purge (vent) system isolation valves may be open dur-

, ing MODES 1, 2, 3, and 4 in a calendar year is determined by the actual need for opening the valves for safety-related reasons; e.g., containment pressure control or the reduction of airborne radioactivity to facilitate personnel access for surveillance and maintenance activities.

Leakage integrity tests with a maximum allowable leaka~ge rate for contain-ment purge supply and exhaust supply valves will provide early indication of resilient material seal degradation and will allow opportunity for repair before gross leakage failures could develop. The 0.60 L leakage limit of a

Specification 3.6.1.2b. shall not be exceeded when the leakage rates determined by the leakage integrity tests of these valves are.added to the previously-determined total for all valves and penetrations subject to Type B and C tests.

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SEABROOK - UNIT 1 B 3/4 6-2 4

F INSERT A the 36-inch containment shutdown purge supply and exhaust isolation valves are not utilized during operation in MODES 1, 2, 3, and 4, and a blind flange is installed establishing a Type "B" penetration.

The penetration is surveilled

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in accordance with Surveillance Requirement 4.6.1.la in MODES 1, 2, 3, and 4.

Surveillance Requirement 4.6.1.2d is also applicable to this penetration.

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Retype of Proposed Chances j

See. attached retype of proposed changes to Technical Specifications. The attached retype reflects the ~ currently ' issued version of Technical Specifications.

Pending Technical Specification changes or Technical Specification changes issued subsequent to ~

this' submittal are not reflected in the enclosed retype. The enclosed retype should be checked for continuity with Technical Specifications prior to. issuance.

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Revision bars are provided in the right hand margin to designate a change in the text.

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CONTAINMENT SYSTEMS d

l PRIMARY CONTAINMENT l

CONTAINMENT LEAKAGE

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SURVEILLANCE REOUIREMENTS

4. 6.1. 2 ' (Continued)

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d.

Type B and C tests shall be conducted with gas at'a pressure not l

less than P, 49.6 psig, at intervals no greater than 24 months 1 i

except for tests involving:

1)

Air locks, and 2)

Purge supply and exhaust isolation valves with' resilient material seals.

e.

The combined bypass leakage rate shall be determined to be less than or equal to 0.60 L, by applicable Type B and C tests at least i

once per 24 months.

f.

Purge supply and exhaust isolation valves with resilent material seals shall be tested and demonstrated OPERABLE by the requirements of Specification 4.6.1.7.1.

g.

Air locks shall be tested and demonstrated OPERABLE by the requirements of Specification 4.6.1.3; and h.

The provisions of Specifications 4.0.2 are not applicable.

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SEABROOK - UNIT 1 3/4 6-4 Amendment No.

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n CONTAINMENT SYSTEMS ERIMARY CONTAINMENT CONTAINMENT VENTILATION SYSTEM LIMITING CONDITION FOR OPERATION 3.6.1.7 Each 8-inch containment purge supply and exhaust isolation valve shall be OPERABLE and sealed closed except when open for purge system operation for-pressure control; for ALARA, respirable, and air quality considerations to.

facilitate personnel entry; and for surveillance tests that require the valve (s) to be open.

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

ACTION:

a.

With one or more of the 8-inch containn.ent purge supply or exhaust isolation valves open for reasons other than given in Specifica-tion 3.6.1.7 above, close the open 8-inch valve (s) or 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 />, otherwise be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

b.

With one or more containment purge supply or exhaust isolation valves having a measured leakage rate in excess of the limits of Specification 4.6.1.7.1, restore the inoperable valve (s) to OPERABLE status or isolate the affected penetration (s) so that the measured leakage rate does not exceed the limits of Specification 4.6.1.7.1 within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and close the purge supply if the affected penetration is the exhaust penetration, otherwise be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

SEABROOK'- UNIT 1 3/4 6-12

-Amendment No.

CONTAINMENT SYSTEMS PRIMARY CONTAINMENT CONTAINMENT VENTILATION SYSTEM r

SURVEILLANCE RE0UIREMENTS I

4.6.1.7.1 At least once per 92 days each.8-inch containment 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 i

0.01 L, when pressurized to P,.

t 4.6.1.7.2 Each 8-inch containment purge supply and exhaust isolation valve shall be verified to be sealed closed or open in accordance with Specification 3.6.1.7 at least once per 31 days.

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.SEABROOK - UNIT 1 3/4 6-13 Amendment No.

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CONTAINMENT SYSTEMS BASES 3/4.6.1 PRIMARY CONTAINMENT (Continued) 3/4.6.1.5 AIR TEMPERATURE The limitation in containment average air temperature ensures that the containment average air temperature does not exceed the initial temperature condition assumed in the overall safety analysis for a steam line break acci-dent. Measurements shall be made at all listed locations, whether by fixed or portable instruments, prior to determining the average air temperature.

3/4.6.1.6 CONTAINMENT VESSEL STRUCTURAL INTEGRITY This limitation ensures that the structural integrity of the containment steel vessel will be maintained comparable to the original design standards for the life of the facility.. Structural integrity is required to ensure that the vessel will withstand the maximum pressure of 52 psig in the event of a LOCA.

A visual inspection in conjunction with Type A leakage tests is sufficient to demonstrate this capability.

3/4.6.1.7 CONTAINMENT VENTILATION SYSTEM The 36-inch containment purge supply and exhaust isolation valves are required to be sealed closed during plant operation since these valves have not been demonstrated capable of closing during a LOCA or steam line break accident. Maintaining these valves closed during plant operations ensures that excessive quantities of radioactive materials will not be released via the Containment Purge System. To provide assurance that these containment valves cannot be inadvertently opened, the 36-inch containment shutdown purge supply and exhaust isolation valves are not utilized during operation in MODES 1, 2, 3, and 4, and a blind flange is installed establishing a Type "B" penetration.

The penetration is wrveilled in accordance with Surveillance Requirement.

4.6.1.la in MODES 1 2, 3, and 4.

Surveillance Requirement 4.6.1.2d is also applicable to this penetration.

The use of the containment purge lines is restricted to the 8-inch purge supply and exhaust isolation valves since, unlike the 36-inch valves, the 8-inch valves are capable of closing during a LOCA or steam 1.ine break accident. Therefore, the SITE BOUNDARY dose guideline values of-10 CFR Part 100 would not be exceeded in the event of an accident during containment PURGING operation. The total. time the containment purge (vent) system isolation valves may be open during MODES 1, 2, 3, and 4 in a calendar year is determined by the actual need for opening the valves for safety-related reasons; e.g., containment pressure control or the reduction of airborne radioactivity to facilitate personnel access for surveillance and maintenance activities.

Leakage integrity tests with a maximum allowable leakage rate for containment purge supply and exhaust supply valves will provide early L

indcation of resilient material seal degradation and will allow opportunity for repair before gross leakage failures could develop..The 0.60 L, leakage i

limit of Specification 3.6.1.2b. shall not be exceeded when the leakage' rates determined by the leakage integrity tests of these valves are added to the previously determined total for all valves and penetrations subject to. Type'B

-and C tests.

SEABROOK - UNIT 1 B 3/4 6-2 Amendment No.

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Safety Evaluation of License Amendment Recuest 93-05 Proposed Channes ii The purpose of License Amendment Request 93-05 is to propose changes to the Seabrook l

Station Technical Specifications to permit a modification of the Containment Structure Air Purge and Heating Subsystem (CAP) to provide a more reliable means of containment isolation for the two containment penetrations (containment purge supply and exhaust) i associated with this system. The primary function of the CAP System is to reduce

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airborne activity levels in the containment atmosphere prior to and during personnel entry l

following a reactor shutdown. The system also serves to maintain minimum containment j

temperature during refueling operations. During all other modes of operation (Modes 1, 2, 3 and 4), the CAP System is precluded from operating pursuant to Technical Specification Limiting Condition for Operation 3.6.1.7a. which requires *feJach containment purge supply and exhaust isolation valve shall be OPERABLE and each 36-inch containment shutdown purge supply and exhaust isolation valve shall be closed and locked closed". The containment isolation design for the CAP System in Modes 1-4 currently employs two 36-inch butterfly valves in each penetration as the isolation valves to address -

10CFR50, Appendix A, General Design Criterion 56 requirements. The purge supply i

penetration isolation valves are designated as CAP-VI (outboard) and CAP-V2 (inboard).

j The purge exhaust penetration isolation valves are designated as CAP-V4 (outboard) and -

CAP-V3 (inboard).

Currently, containment isolation for the purge supply and exhaust penetrations is

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provided by a butterfly valve and blind flange for each penetration. Valves CAP-V2 (purge supply, inboard) and CAP-V4 (purge exhaust, outboard) were replaced by blind flanges prior to startup from the second refueling outage due to degradation of their leak l

tightness. The large butterfly valves with their resilient seals are susceptible to seal

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degradation when the valves are intermittently stroked during surveillance testing and

.7 during normal system operation. Alternatively, by replacing the valves with testable blind l

flanges, their concentric O-ring seals will not have been exposed to the dynamic forces L

of valve operation which can. induce seal wear and degrade the leak tightness of the containment penetration.

The CAP System modification planned by North Atlantic will replace the two outboard i

containment isolation valves (CAP-V1 and CAP-V4) with testable blind flanges during l

Modes 1,2,3 and 4. The blind flanges will form the containment pressure 1 oundary for

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the penetrations and will provide primary containment isolation in Modes 1,2,3 and 4.

The isolation valves in the CA P penetrations will no longer be required for containment I

isolation in Modes 1, 2, 3, and 4 The new configuration for the CAP penetrations will

'j comply with 10CFR50, Appendix A, Geucral Design Criterion 50 requirements. During '

Modes 5 and 6, to permit operation of the CAP system, the blind flanges will be removed j

and transition spool pieces will be installed. The isolation valves, CAP-VI and CAP-V4 i

will be permanently reinstalled outboard of the transition spool pieces to be available for j

containment closure in Modes 5 and 6.

The use of testable blind flanges is a more

.l reliable design for CAP penetration isolation than the use of the 36-inch butterfly valves.

i The blind flanges, existing weld neck flanges and bolting material will be classified as l

ASME Section Ill Code Class MC (Metal Containment) which is the same ASME Code

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classification as the equipment and personnel hatches and fuel transfer tube hatch, which l

also utilize resilient seals and are Type B tested. North Atlantic has performed an j

engineering evaluation which establishes the basis for classification of.the CAP penetrations as ASME Code Class MC. A copy of this the engineering evaluation is enclosed (See Section Vill). The CAP penetrations will be tested as Type B penetrations.

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in accordance with the requirements of UFSAR Section 6.2.6.2 and 10CFR50, Appendix I

J,Section III.B.

The pressure sealing design for these blind flanges includes two j

concentric o-rings. Since the blind flanges utilize resilient seals in the design of the i

penetration as part of the pressure boundary,it is required by UFSAR Section 6.2.6.2 and 10CFR50, Appendix J, Section III.G.1, that these penetrations be tested as Type B. The blind flanges have a test port and a groove incorporated into the design to allow for testing between the o-ring seals. Another port, located 180* circumferentially from the j

first port, is provided to verify that no blockage exists in the groove. UFSAR Section j

6.2.6.2 describes the acceptable methods of Type B testing using the pressure decay or the makeup flow method. The frequency of Type B and Type C leakage rate tests are l

specified in UFSAR Sections 6.2.6.2 and 6.2.6.3 respectively. UFSAR Section 6.2.6.2 states that all penetrations requiring Type B testing be tested at a frequency. not to exceed two years. UFSAR Section 6.2.6.3 states that Type C tests be performed.. in no case at intervals greater than two years. The UFSAR specified test frequencies con-ur' with the test frequencies specified in 10CFR50, Appendix J and Technical Specification Surveillance Requirement 4.6.1.2.

Technical Requirement 16, Table 16.3-11, Secondary Containment Bypass Leakage Paths, currently lists CAP System containment penetrations HVAC-1 and HVAC-2 as bypass

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leakage paths. Additionally, these penetrations are listed as bypass leakage paths in.

UFSAR Table 6.2-83.

Th,ese penetrations (including their associated piping and ductwork) presently terminate in the Primary Auxiliary Building, therefore, containment leakage from the subject penetrations would not be processed and cleaned by the Containment Enclosure Emergency Air Handling System (EAH). The two primary j

functions of EAH system as specified in UFSAR Section 6.2.3.2c. are to produce a negative pressure after an accident in the annular, cylindrical volume between the containment and containment enclosure and to collect any leakage into these areas from the containment structure or equipment / systems located within the enclosure so that they q

may be disposed of in a controlled manner. Both of these functions are performed by redundant filter trains, redundant fans, dampers and controls, and a common discharge ductwork system to the plant vent. The planned modification will replace the two CAP 3

system 36-inch butterfly valves located outside of containment with testable blind flanges -

l and will result in these penetrations terminating within the containment enclosure ventilation area (CEVA). Since the subject p*:1.ctrations will terminate in the CEVA, all primry r.nhi,cust ?enby from them -ill de processed through the EAH system. As i

a result, the CAP penetrations are no longer required to be listed as bypass penetrations -

i in Technical Requirement 16, Table 16.3-11.

UFSAR Table 6.2-83, Containment Isolation System Design Information, Sheet 12 of 13, i

lists these containment penetrations as Type I 1ecause they connect directly to the containment atmosphere.

l UFSAR Section 6.2.4.2d.1= applies the following valve arrangement criteria to Type I penetrations:

(a)

One locked-closed isolation valve inside and one locked-closed isolation valve; l

outside containment; or.

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(b)

One automaticisolation valve inside and one locked-closed isolation valve outside E

containment; or 8

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(c)

One locked-closed isolation valve inside and o'ne automatic isolation valve outside -

containment ; or j

(d)

. One automatic isolation valve inside and one automatic isolation valve outside -

I containment.

i These containment isolation provisions are in accordance with 10CFR50, Appendix A, f

General Design Criterion.56.

j The existing plant design for the subject ' penetrations meets criterion (d) of the above design configurations.. The planned modification to the containment isolation provisions -

3 for the CAP System will not rely on containment isolation valves to provide containment' t

integrity for the CAP penetrations. Alternatively,in Modes 1-4, the testable blind flanges

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in the CAP penetrations will form part of the containment pressure boundary and will1 provide primary containment isolation in these Modes. UFSAR Section 6.2.4.1c. specifies j

that sealed closed barriers which replace automatic isolation valves may include blind j

flances and locked-closed isolation vs.'ves. These barriers, which remain closed after a LOCA, will be managed through administrative controls. Additionally, ANSI. N271-1976 l

Section 4,10, which is approved for use by NRC Regulatory Guide 1.141, allows the use 1

of flanged closures under administrative controls as long as the closures are tested to the' provisions of 10CFR50 Appendix J. Since the replacement blind flanges are:(1) designed.

to meet ASME III, Code Class MC, (2) will be administratively controlled during l

operational Modes 1,2,3, and 4, and (3) the penetrations are tested in accordance with 10CFR50 Appendix J; their use will ensure a reliable means of containment isolation for.

the CAP penetrations.

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Determination of Sicnificant llarards for I lcense Amendment Rennest 93-05 Pronosed Chances significant increase in the probability or j

(1)

The proposed changes do not involve a consequences of an accident previously evaluated.

The proposed Technical Specification changes are submitted in support of a planned modification of the Containment Structure Air Purge and Heating Subsystem (CAP). This planned modification replaces the 36-inch Containment purge supply and exhaust isolation valves, CAP-VI and CAP-V4, (located outside containment) with testable blind flanges i

during operational Modes 1, 2, 3 and 4, which will form a part of the containment pressure boundary. The 36-inch butterfly valves in the CAP penetrations will no longer be required for containment isolation in Modes 1, 2, 3, and 4. The replacement of the subject valves with blind flanges provides a more reliable containment isolation design for the CAP penetrations. The alternative design is not susceptible to the resilient seal 1

degradation process that is inherent with the operation of the 36-inch butterfly valves.

During Modes 5 and 6, to permit operation of the CAP system, the blind flanges will bc removed and transition spool pieces will be installed. CAP valves CAP-V1 and CAP-V4 will be permanently reinstalled outboard of the transition spool pieces in order to be available for containment closure in Modes 5 and 6, if necessary. Chapter 15 of the Seabrook Station Updated Final Safety Analysis Report (UFSAR) provides the results of the analysis of a fuel handling accident inside containment where the CAP valves would l

be required for containment isolation. In the event that a fuel assembly is dropped during fuel handling operations inside containment, operating procedures require personnel to leave immediately and operators to isolate the CAP System. In addition, redundant area radiation monitors in the vicinity of the manipulator crane will alarm on high activity and automatically secure the CAP System. The ability of the CAP valves to close within the time assumed in fue!, handling accident analysis will continue to be j

verified during the stroke ' testing or the CAP valves per Procedure "OX1423 24, Certei.m iur Purge Valve Testing, Cold Shutdown". The planned modification and j

proposed Technical Specification changes do not affect any of the initiating conditions i

nor does it affect the consequences of accidents evaluated in Chapter 15 of the UFSAR, therefore neither the probability of an accident nor the consequences of an accident will be increased.

(2)

The proposed changes do not create the possibility of a new or different kind of accident f

from any accident previously evaluated.

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The primary function of the CAP system is to reduce airborne activity levels in the

-f containment atmosphere during refueling operations and prior to and during personnel l

entry following a reactor shutdown. The system also serves to maintain minimum containment temperatures during refueling operations. During all other modes of operation (Modes 1, 2, 3 and 4), the CAP system is idle and not available.for use.

Additionally, power is removed from the containment isolation valves (CAP-VI, CAP-V2, l

CAP-V3 and. CAP-V4). Other than the containment isolation function during operational Modes 1, 2,3, and 4 the CAP System serves no safety related function and does not l

directly affect the operation of any other safety related system. Since the replacement i

blind flanges will provide a superior containment isolation design for the CAP System which meets ASME Code requirements for Metal Containment (MC), and is to be tested in accordance with the requirements of UFSAR Section 6.2.6.2. and 10CFR50, Appendix--

J, Section 111.B, there is no possibility of creating a new or different type of accident than any previously evaluated.

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The proposed changes do not result in a significant reduction in the margin of safety.

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North Atlantic plans to replace the two outboard containment isolation valves (CAP-V1 and CAP-V4) with testable blind flanges to provide a more reliable containment isolation i

design than the current design that utilizes 36-inch butterfly valves. The butterfly valves i

are susceptible to seal degradation when the valves are intermittently stroked during surveillance testing and during normal system operation. Alternatively, by replacing the

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butterfly valves with testable blind flanges, the concentric o-ring seals.on the blind flanges are not exposed to the dynamic forces of valve operation which can induce seal wear' and degrade the leak tightness of the penetration boundary. The blind flenges, existing weld.

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neck flanges and bolting material will be classified as ASME Section III, Code Class MC (Metal Containment) which is the same ASME Code classification as for the equipment and personnel hatches and fuel transfer tube hatch. North Atlantic has performed an.

i engineering evaluation which establishes the basis for classification of the CAP penetrations as ASME Code Class MC. A copy of this the engineering evaluation is i

enclosed (See Section VIII). Additionally, the penetrations will be tested as Type B 4

penetrations in accordance with the requirements of UFS AR section 6.2.6.2 and 10CFR50, Appendix J, Section llI.B (Type B). Since the replacement blind flanges will provide a superior containment isolation design for the CAP System which meets ASME Code.

requirements for Metal Containment (MC), and is to be tested in accordance with the requirements of UFSAR Section 6.2.6.2 and 10CFR50, Appendix J, there is no reduction in the margin of safety, i

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i VI.

Proposed Schedule for License Amendment Issuance and Effectiveness i

North Atlantic requests NRC review of License Amendment Request 93-05 and issuance j

of a license amendment having immediate effectiveness by November 7,1993 with j

implementation required prior to startup from the third refueling outage.

The planned modification to the CAP System containment isolation provisions provides

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a superior design to the current design. The current design utilizes 36-inch butterfly valves for containment isolation in Modes 1, 2, 3, and 4 The butterfly valves are susceptible to seal degradation when the valves are intermittently stroked during l

surveillance testing and during normal system operation. Alternatively, by replacing the.

butterfly valves with testable blind flanges, the concentric o-ring seals on the blind flanges :

l are not exposed to the dynamic forces of valve operation which can induce seal wear and I

degrade the leak tightness of the penetration boundary.

t North Atlantic plans to implement the CAP System modification during the next refueling outage which is scheduled to begin in March 1994.

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l VII.

Environmental !mpact Assessment j

North Atlantic has reviewed the proposed license amendment against the criteria of 10CFR5L22 for environmental considerations. The proposed changes do not involve a significant hazards consideration, nor increase the types and amounts of effluents that j

may be released offsite, nor significantly increase individual or cumulative occupational j

radiation exposures. Based on the foregoing, North Atlantic concludes that the proposed change meets the criteria delineated in 10CFR51.22(c)(9) for a categorical exclusion from lj the requirements for an Environmental Impact Statement.

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VIII. - Supportine Information l

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Engineering Evaluation Number 93-02; "ASME Code Classification for Containment i

Penetrations HVAC-1 and HVAC-2" 1

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