ML20045D584
| ML20045D584 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 06/18/1993 |
| From: | NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO) |
| To: | |
| Shared Package | |
| ML20045D578 | List: |
| References | |
| NUDOCS 9306290182 | |
| Download: ML20045D584 (5) | |
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I II.
- Markun of Proposed Chances See attached markup of proposed changes to Technical Specifications.
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9306290182 930618 3 a PDR ADOCK 05000443
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-l PLANT SYSTEMS i
! TURBINE CYCLE CONDENSATE STORAGE TANK l l
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. LIMITING CONDITION FOR OPERATION 3.7.1.3 The condensate storage tank (CST) system shall be OPERABLE with
- a. A volume of 212,000 gallons of water contained in the condensate r storage tank, and 'l
- b. A concrete CST enclosure that is capable of retaining 212,000 gal-lons of water.
APPLICABILITY: MODES 1, 2, and 3. .
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With the CST or the CST enclosure ipoperable, within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> restore the CST :
and the CST enclosure to OPERABLE status or be in at least HOT STANDBY within l the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in HOT SHUTDOWN within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
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, SURVEILLANCE REQUIREMENTS ,
i 4.7.1.3 a.The CST =d the CST encle:ure shall be demonstrated OPERABLE at l least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by verifying the contained water volume in the CST is within its limits = d th: CST =cic;ure integrity is a,ainteined, b, 77,e c S7~ en clo sure sAaN As c/e m . ,,di sh cl O P S R /* 81 G" at l east once e r. jg y j, by an 1bo Verify f/af CSY i n sf e ed~ ion
- e. n cl 0.s u re t n rey r thy is M a in fa in c c/.
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SEABROOK - UNIT 1 3/4 7-6 l
III.- Retype of Proposed Channes 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.
Revision bars are provided in the right hand margin to designate a change in the text.
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PLANT SYSTEMS TURBINE CYCLE CONDENSATE STORAGE TANK LIMITING CONDITION FOR OPERATION 3.7.1.3 The condensate storage tank (CST) system shall be OPERABLE with
- a. A volume of 212,000 gallons of water contained in the condensate storage tank, and
- b. A concrete CST enclosure that is capable of retaining 212,000 gallons of water.
APPLICABILITY: MODES 1, 2, and 3.
ACTION: .
With the CST or the CST enclosure inoperable, within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> restore the CST and the CST enclosure to OPERABLE status or 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 HOT SHUTDOWN within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
SURVEILLANCE RE0UIREMENTS 4.7.1.3a. The CST shall be demonstrated OPERABLE at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by verifying the contained water volume in the CST is within its limits.
- b. The CST enclosure shall be demonstrated OPERABLE at least once per 18 months by an inspection to verify that CST enclosure integrity is maintained.
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l SEABROOK - UNIT 1 3/4 7-6 Amendment No. ,
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IV. Safety Evaluation of License Amendment Request 93 09 Proposed Channes i
The purpose of License Amendment Request 93-09 is to propose changes to the Seabrook Station Technical Specifications to reduce the frequency of surveillances which are required to verify the integrity of the Condensate Storage Tank (CST)
Enclosure.
. The Condensate Storage Tank (CST) provides a sufficient volume of water to ensure
' that the Reactor Coolant System (RCS) can be cooled to hot shutdown conditions ,
following a design basis accident. The CST is verified OPERABLE as required by Technical Specification Surveillance Requirement 4.7.1.3 at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by verifying that the contained water volume is equal to or greater than 212,000 gallons.
The CST is protected on its sides by a tornado missile proof concrete structure, the j CST Enclosure, which is designed to ensure the availability of the water volume following the rupture of the CST by a tornado generated missile entering the top of the CST. The CST Enclosure is demonstrated OPERABLE as required by Technical Specification Surveillance Requirement 4.7.1.3 at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by verifying that integrity is maintained.
l The CST Enclosure integrity verification required by Surveillance Requirement 4.7.1.3 is performed each shift by an Auxiliary Operator. The Auxiliary Operator verifies the integrity of the CST Enclosure by observing the immediate concrete enclosure around the tank and the seals associated with the enclosure penetrations do not have work ongoing that may cause degradation. The CST Enclosure and its seals are passive devices that are not exercised during plant operations and which are not subject to transient or cyclical forces from the normal operation of the plant. The most likely failure mode for the penetration seals is long term degradation due to aging. The 12 ;
e hour surveillance frequency would be appropriate for identifying an active condition i or parameter but is not appropriate for a condition that would take many years to ,
develop. l The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> frequency for performance of this surveillance is burdensome to the operating crews in that it diverts an Auxiliary Operator for a short time each shift to perform an activity that does not provide substantial information related to the integrity of the Enclosure. The most likely activity to affect the integrity of the CST Enclosure is maintenance affecting the penetration seals. Maintenance activities on the CST Enclosure seals would be performed in accordance with the Station work control program and if it occurred in MODES 1,2 or 3 it would necessitate entry into the Action Statement of Technical Specification 3.7.1.3 for the Enclosure being inoperable. In all cases, the work control program would require the verification of the Enclosure integrity at the completion of the maintenance activity and prior to entry into MODE 3 when work is performed in MODES 4,5 or 6.
Therefore, LAR 93-09 proposes a revision to Surveillance Requirement 4.7.1.3 to verify that the CST Enclosure is OPERABLE at least once per 18 months by an inspection to verify that CST Enclosure integrity is maintained. The proposed 18 month frequency for performance of the CST Enclosure inspection is consistent with the required frequency for the Containment Enclosure drawdown test (Surveillance Requirement 4.6.5.1 d.4). The Containment Enclosure drawdown test is effectively verifying the leak-tightness of the Containment and the Containment Enclosure.
The inspection of the CST Enclosure and seals will be similar to inspections performed on the containment prior to Type A testing as required by 10CFR50 5
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. Appendir J,Section V.A. The CST Enclosure and CST sealinspection procedure will involve a general inspection of the accessible surfaces to uncover any evidence of enclosure structural deterioration or seal degradation which anay affect either the CST structural integrity or leak tightness. The inspection of the CST Enclosure and seals will be performed by personnel from the Station Technical Support organization, the organization that performs similar inspections of the Containment and Containment Enclosure. The Technical Support personnel possess the requisite expertise and knowledge to detect potential degradation of the CST Enclosure.
Therefore their inspection provides a superior inspection to that performed- by Auxiliary Operators.
In conclusion, the proposed revision to the CST enclosure surveillance frequency will not adversely affect the safe operation of Seabrook Station. The inspection of the CST enclosure will be conducted at an appropriate frequency (e.g.18 months) for j passive devices that are not exercised during plant operation and are not subject to transient or cyclical forces from the normal operation of the plant. '!
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s V. - Determination of Slenifica n t Hazards for License Amendment Reauest 93 09 Proposed Chnnees (1) The proposed changes do not involve a significant increase in the probability or consequences of an accident previously evaluated.
The CST is protected on its sides by a tornado missile proof concrete structure, the CST Enclosure, which is designed to ensure the availability of the water volume following the rupture of the CST by a tornado generated missile entering the top of the CST. Technical Specification Surveillance Requirement 4.7.1.3 requires that the CST Enclosure be demonstrated OPERABLE at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by verifying-that integrity is maintained.
The CST Enclosure integrity verification required by Surveillance Requirement 4.7.1.3 is performed each shift by an Auxiliary Operator. The Auxiliary Operator verifies the integrity of the CST Enclosure by observing the immediate concrete enclosure around the tank and the seals associated with the enclosure penetrations do not have work ongoing that may cause degradation. The CST Enclosure and its seals are passive ;
devices that are not exercised during plant operations and which are not subject to transient or cyclical forces from the normal operation of the plant. The most likely failure mode for the penetration seals is long term degradation due to aging. The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> surveillance frequency would be appropriate for identifying an active condition or parameter but is not appropriate for a condition that would take many years to develop.
The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> frequency for performance of this surveillance is burdensome to the operating crews in that it diverts an Auxiliary Operator for a short time each shift to perform an activity that does not provide substantial information related to the i integrity of the CST Enclosure. The most likely activity to affect the integrity of the CST Enclosure is maintenance affecting the penetration seals. Maintenance activities on the CST Enclosure seals would be performed in accordance with the Station work control program and if it occurred in MODES 1,2 or 3 it would necessitate entry into the Action Statement of Technical Specification 3.7.1.3 for the Enclosure being inoperable. In all cases, the work control program would require the verification of the Enclosure integrity at the completion of the maintenance activity and prior to entry into MODE 3 when work is performed in MODES 4,5 or 6.
Accident analyses assume the availability of a CST water volume sufficient to cool the Reactor Coolant System (RCS) to a temperature of 350*F. The OPERABILITY of the concrete CST Enclosure ensures this availability of water following rupture of the CST by a tornado generated missile. The proposed revision to the CST Enclosure surveillance frequency will not affect the probability of a tornado-induced accident (e.g. Loss of Offsite Power) with a tornado missile striking and rupturing the CST.
The probability of this sequence of events is estimated at 1.1E-7 as documented in the Seabrook Station Probabilistic Safety Assessment (SSPSA), PLG-0300, December 1983. Under this highly improbable sequence of events, the CST Enclosure would be required to preserve the minimum required CST water volume in the CST Enclosure.
l The failure of the CST Enclosure during this accident sequence is itself improbable
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due to the relatively low hydrostatic pressure in the vented CST. The proposed revision to the CST Enclosure integrity verification will not significantly increase the probability or consequences of a tornado-induced accident sequence.
The CST Enclosure 18 month inspection will be more comprehensive than the current inspection which is performed each shift by Auxiliary Operators. The inspection of the CST Enclosure and seals will be performed by personnel from the Station Technical Support organization, the organization that performs similar inspections of 7
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the Containment and Containment Enclosure. The Technical Support personnel possess the requisite expertise and knowledge to detect potential degradation of the CST Enclosure. Therefore their inspection provides a superior inspection to that performed by Auxiliary Operators.
(2) The proposed cbuges do not create the possibility of a new or different kind of I accident from an, accident previously evaluated, t
The CST Enclosure is designed to preserve the CST water volume during a tornado-induced accident sequence as discussed above. The CST Enclosure performs a '
passive function and the proposed revision to the CST Enclosure integrity verification frequency will not affect the design, properties or function of the CST Enclosure nor will it affect the ability of the CST Enclosure to perform its design safety function.
Therefore the change proposed by License Amendment Request 93-09 does not create the possibility of a new or different kind of accident from any accident previously evaluated.
(3) The proposed changes do not result in a significant reduction in the margin of safety.
License Amendment . Request 93-09 proposes a revision to the frequency of the performance of a surveillance requirement to verify the integrity of the Condensate Storage Tank (CST) Enclosure. The proposed revision does not modify or change the plant nor does it revise any aspects of plant operation nor its operating procedures.
The proposed revision addresses only an inspection activity that does not revise any procedures or activities regarding the cycling or operation of plant equipment. The proposed revision does not introduce any new or different failure mechanisms nor potential equipment malfunctions nor does it affect the response of the plant to any operational transient or its response to any accident previously evaluated in the UFSAR. The proposed frequency of CST Enclosure inspections does not invalidate -
any assumptions nor accident analyses presented in Chapter 6 and 15 of the UFSAR. ,
The CST Enclosure is designed to contain the CST water volume in the event the CST
- is ruptured by a tornado missile. The proposed revision to the Enclosure inspection
! frequency does not affect the probability of a tornado missile being generated and it also does not affect or accelerate any failure mechanism for the Enclosure.
The proposed revision to the surveillance frequency does not affect the integrity of the CST Enclosure and does not revise its capabilities and also does not resise the conclusion reached on Page B 3/4 7-2 of the Bases for Technical Specification 3/4.7.1.3, Condensate Storage Tank, nor the description of the Enclosure's functions as described in UFSAR Section 3.8.4.1.g. Therefore, with consideration of the above, LAR 93-09 does not reduce the margin of safety as defined in the Bases 'of the Technical Specifications.
The inspection of the CST Enclosure will be similar to inspections performed on the containment prior to Type A testing as required by 10CFR50 Appendix J, Section V.A. The CST Enclosure inspection procedure will involve a general inspection of the accessible surfaces and penetration seals to uncover any evidence of structural deterioration or seal degradation which may affect either the CST structuralintegrity-or leak-tightness. The CST Enclosure 18 . month inspection will ' be more comprehensive than the current inspection which is performed each shift by Auxilia y Operators. The CST Enclosure 18 month inspection will be developed and performed by North Atlantic Technical Support Department personnel who are experienced in the performance of Type A containment leak rate testing.
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VI. Proposed Schedule for License Amendment issunnee and Effectiveness North Atlantic requests NRC review of License Amendment Request.93-09 and issuance of a license amendment having immediate effectiveness by December 30, 1993.
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V I I .- Environmental Impact Assessment North Atlantic has reviewed the proposed license amendment against the criteria of 10CFR51.22 for environmental considerations. The proposed changes do not involve a significant hazards consideration, nor increase the types and amounts of effluents that may be released offsite, nor significantly increase individual or cumulative 1 occupational radiation exposures. Based on the foregoing, North Atlantic concludes that the proposed change meets the criteria delineated in 10CFR51.22(c)(9) for a j categorical exclusion from the requirements for an EnvironmentalImpact Statement. l l
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