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Application for Amend to License NPF-86,revising TS 3.9.4 That Addresses Containment Bldg Penetrations to Allow Use of Alternate Containment Bldg Penetration Closure Methodologies for Postulated Accident Scenarios During Core Alterations
	ML20082L500
Person / Time
Site:	Seabrook
Issue date:	04/17/1995
From:	Drawbridge B; NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO)
To:	; NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20082L492	List: ML20082L490; ML20082L500; ML20082L521;
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	NUDOCS 9504210191
	Download: ML20082L500 (8)
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SEABROOK STATION UNIT 1 Facility Operating License NPF-86 Docket No. 50-443 License Amendment Request No. 94-06 Revision to Technical Specification 3.9.4, Containment Building Penetrations This License Amendment Request is submitted by North Atlantic Energy Service Corporation pursuant to 10CFR50.90. The following information is enclosed in support of this License Amendment Request:

Section 1 - Introduction and Safety Evaluation for the Proposed Changes Section 11 - Markup of Proposed Changes Section ill -

Retype of Proposed ChangesSection IV - Determination of Significant Hazards for License Amendment Request 94-06 Proposed ChangesSection V -

Proposed Schedule for License Amendment issuance and EffectivenessSection VI -

EnvironmentalImpact Assessment !

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l Swom and Subscribed l to be ore me this i

/7 I day of MM ,1995 l NdU "

kf&, Bruce/ AJ/ L. Drawbridg[

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(./ Notary Public Executive Director - Nucledr Production 9504210191 950416 PDR ADOCK 05000443 P PDR

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lJ. ,,, Introduction and Safety Evaluation for the Proposed Chances A. Introduction The purpose of License Amendment Request 94-06 is to propose two changes to the Seabrook Station Technical Specifications that address containment building penetrations. The first change is to allow the use of alternate closure methods for containment building penetrations during core '

alterations or movement of irradiated fuel within containment. The second change would allow both personnel airlock doors to be open during core alterations or movement ofirradiated fuel j within containment. In addition the Bases for Technical Specification 3.9.4 would be revised to j include a discussion for both changes.

Chance 1 - Containment Penetrations l

Technical Specification 3.9.4.c (penetrations) states that each penetration providing direct access from the containment atmosphere to the outside atmosphere shall be closed by an isolation valve, ,

I blind flange, or manual valve. These requirements are applicable during core alterations or movement of irradiated fuel within the containment.

The proposed change would include a third alternative to technical specification 3.9.4.c for assuring containment closure capability. The third alternative would require that the penetration be capable of being closed by a designated individual available at the penetration. In addition, j the use of methods " equivalent" to closed valves and blind flanges to achieve containment closure j are included in the proposed change. The use of " equivalent" methods are included in the j Westinghouse Standard Technical Specifications (NUREG-1431) and must be approved by an i engineering evaluation. The equivalent methods will provide an atmospheric pressure and ventilation barrier and will ensure that penetrations providing direct access from inside containment to outside containment are capable of restricting a release of radioactive material to the environment. This change would provide flexibility in the scheduling of certain outage activities during periods when containment closure is required.

An example of an activity that would benefit from the presence of a dedicated individual available to close a penetration is steam generator sludge lancing. Steam generator sludge lancing is l performed to remove sludge, which accumulates during power operation, from the tubesheet on l the secondary side of the steam generators. This is currently accomplished by routing hoses from an area outside of containment to a sludge lance outage fixture attached to a spare outside containment penetration. The sludge lance outage fixture is fabricated from a blind flange with threaded sleeve ports. The sleeve ports provide connection points for sludge lance hoses. The connection points for the sludge lance hoses are equipped with quick closing ball valves for isolation. During core derations or movement ofirradiated fuel within the containment, sludge lancing operations are stopped and the manual isolation valves closed. j 1 \

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Because the containment must be closed pursuant to Technical Specif' cation 3.9.4.c.1, sludge lancing must currently be performed during a time when there are no core alterations or movement of irradiated fuel within containment. This does not allow flexibility in the performance of sludge lancing, since there are only short periods of time during a typical refueling

outage, in which the technical specifications will allow the containment to be open to the I

atmosphere.

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,' [, Containment closure capability means that all potential escape paths from the containment are .

closed or capable of being closed. it is being proposed that an alternate closure methodology be utilized to provide containment closure capability for postulated accident scenarios during core alterations or movement ofirradiated fuel within containment. The alternate containment closure i method would include the use of a administrative controls and a designated individual to close the i isolation valves in the event of a Fuel 11andling Accident. Referring to the example, this would allow steam generator sludge lancing to continue during times when containment closure is ;

required which will simplify outage scheduling and assist in reducing the length of refueling !

outages. !

A similar TechnicalSpecification change has been approvedfor the Wolf Creek Nuclear Power :

Station (Amendment 74 to NPF-42). :

Chance 2 - Personnel Airlock Doors Technical Specification 3.9.4.b (personnel airlock doors) states that a minimum of one door in l each airlock, as well as other containment penetrations, be closed during core alterations or movement of irradiated fuel within the containment. As described in Technical Specification ;

Bases 3.9.4, the purpose of this requirement is to ensure that a release of radioactive material within containment will be restricted from leakage to the environment. ,

For the purposes of this License Amendment Request, " personnel airlock doors" refers to the main .

personnel airlock doors or the equipment hatch personnel airlock doors. Only one set of personnel i airlock doors may remain open during core alterations or movement of irradiated fuel within ;

containment. The proposed change would allow both personnel airlock doors to be open during ,

core alterations or movement of irradiated fuel within containment. The following changes are ,

proposed to Technical Specification 3.9.4.b, " Containment Building Penetrations". ,

b) "A minimum of one door in each airlock is closed, however, both doors of one personnel i airlock may be open if:

1) one personnel airlock door is capable of being closed, and :

2) a designated individual is available outside the personnel airlock to close the i door" During a refueling outage, other work in the containment does not stop during fuel movement and ,

core alterations. This requires that personnel operate the personnel airlock (PAL) doors to enter and exit the containment. During a refueling outage, when containment closure is required for fuel movement, the PAL doors are operated up to several hundred times per day for access into containment. Such heavy use of the PAL doors was not anticipated during its design. As a result j of this heavy use, failures of the door hinge pin, the door seals, and other components have occurred. Trained, dedicated door operators have been used in an effort to mir,imize damage to !

the door, but problems have persisted. These failures of the PAL doors raise the concern that the ,

PAL might not be able to be closed in the event of an accident.

From a practical standpoint, Specification 3.9.4 will not prevent all radioactive releases from the '

containment following a Fuel llandling Accident. There are a large number of people in the containment during a refueling outage, even during fuel movement and core alterations. Should j a Fuel llandling Accident occur, it would take a number of cycles of the airlock doors to evacuate !

personnel from the containment. With each PAL cycle, more containment air would be released.

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F a-l[ [,While waiting for their turn to exit,' the workers would be exposed to the released activity.

Alternatively, the Shift Superintendent could invoke 10 CFR 50.54(x), and order both PAL doors opened while the personnel in the containment are evacuated, and then close the doors. In either case, there could be a release of activity into the atmosphere. Under the proposed change, the containment could be evacuated without invoking 10 CFR 50.54(x) and then the airlock closed.

This would reduce dose to station workers in the event of an accident while maintaining acceptable doses to the public.

A similar Technical Specification change has been approvedfor the Calvert Cliffs Nuclear Power Plant, Units 1 & 2, (Amendment 174 to DPR-53 and Amendment 171 to DPR-69) and South Texas Project, Units 1 & 2, (Amendment 69 to NPF-76 andAmendment 58 to NPF-80).

H. Safety Evaluation for Proposed Changes The following changes are proposed to Technical Specification 3.9.4.c, " Containment Building Penetrations"-

Chance 1 - Containment Penetrations Technical Specification 3.9.4.c (penetrations) is revised by adding a third alternative,3.9.4.c.3 for assuring containment closure capability. The proposed changes to Technical Specification 3.9.4.c.3 read:

3) "Be capable of being closed by a designated individual available at the penetration" In this discussion, "Available" is defined as: Stationed at the penetration or performing activities controlled by a procedure on equipment associated with the penetration.

Surveillance Requirement 4.9.4 is revised by replacing the requirement to verify that the containment building penetrations are in their " closed / isolated" positions to verifying that the containment building penetrations are in their " required" positions. The proposed revision to surveillance requirement 4.9.4 allows for the provision for alternate or equivalent closure methods and is consistent with the wording contained in NUREG-1431, " Standard Technical Specifications for Westinghouse Plants" The addition of a third option to Technical Specification 3.9A.c describes a method other than the explicit use of isolation valves, blind flanges, or manual valves that is acceptable to ensure that containment closure capability is achieved for postulated accident scenarios during core alterations or movement ofirradiated fuel within containment. The alternate closure methodology will ensure that penetrations providing direct access from inside containment atmosphere to outside containment are capable of restricting a release of radioactive material to the environment. The alternate closure methodology consists of a designated individual available to close the penetration for openings up to an equivalent 12" in diameter. The radiological evaluation assumed two scenarios; first, a 0.5 hour5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months closure of the penetration and second, that the penetration remained open aller 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months . The evaluation also assumes that a door in each personnel airlock is closed, since the case with both doors in a personnel airlock open is the limiting case for calculating offsite dose. The radiological evaluation resulted in a maximum offsite dose of 24 Rem to the thymid and 0.74 Rem to the whole body with no credit for penetration isolation. The Standard Review Plan guidelines are 25% of the 10 CFR Part 100 limits, e.g.,75 Rem to the thyroid and 6 Rem to the whole body. Calculated 30 day control room doses are 3.8 Rem to the thyroid and Page 3 l

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,[,0.8 Rem to the whole body and are within the acceptance limit of 5 Rem whole body, or equivalent organ dose of GDC 19. The assumptions and results of the evaluation are included in Attachment 1.

The radiological evaluation confirms by analysis, that the maximum offsite doses are well within the limits prescribed by 10 CFR Part 100, as described in the Standard Review Plan, Section 15.7.4, Revision 1.

In addition, the use of methods " equivalent" to closed valves and blind flanges to achieve containment closure are included in the proposed change. The use of " equivalent" methods are included in the Westinghouse Standard Technical Specifications (NUREG-1431) and must be approved by an engineering evaluation. The equivalent methods will provide an atmospheric pressure and ventilation barrier and will ensure that penetrations providing direct access from inside containment to outside containment are capable of restricting a release of radioactive material to the environment.

Based on the above, the proposed changes to Technical Specification 3.9.4, Surveillance Requirement 4.9.4 and their Bases have been shown to not significantly impact the probability or consequences of an accident previously analyzed.

Chance 2 - Personnel Airlock Doors The proposed change would allow both personnel airlock doors to be open during core alterations or movement of irradiated fuel within containment. The following changes are proposed to Technical Specification 3.9.4.b, " Containment Building Penetrations" and its Bases:

b) "A minimum of one door in each airlock is closed, however both doors of one personnel airlock may be open if:

1) one personnel airlock door is capable of being closed, and

2) a designated individual is available outside the personnel airlock to close the door" Surveillance Requirement 4.9.4 is revised by replacing the requirement to verify that the containment building penetrations are in their " closed / isolated" positions to verifying that the containment building penetrations are in their " required" positions. The proposed revision to surveillance requirement 4.9.4 allows for the provision for alternate or equivalent closure methods and is consistent with the wording contained in NUREG-1431, " Standard Technical Specifications for Westinghouse Plants".

The Basis for Technical Specification 3.9.4 is revised to include a discussion of the containment building penetrations and the personnel airlocks, as follows: i The Limiting Conditionfor Operation (LCO) limits the consequences of afuel handling accident in containment by limiting the potential escape paths forfission product radioactivity released within containment. The LCO requires anypenetration providing direct accessfrom the containment atmosphere to the outside atmosphere to be closed except for the OPERABLE containment purge and exhaust penetrations. the approved alternate closure method and the containment personnel airlock. l Page 4 l

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. .' i For the approved alternate closure method, the LCO requires that a designated individual must be available to close or direct the remote closure of the penetration in the event of afuel handling accident. "Available" means stationed at the penetration or performing activities controlled by a procedure on equipment associated with the penetration.

For the personnel airlocks (containment or equipment hatch), the LCO ensures that the airlock can be closed after containment evacuation in the event of afuel handling accident. The requirement that the airlock door is capable of being closed requires that the door can be closed and is not blocked by objects that cannot be easily and quickly removed. As an example, the use of removable protective covers for the door seals and sealing surfaces is permitted. The requirementfor a designated individual located outside of the airlock area available to close the doorfollowing evacuation of the containment will minimi:e the release of radioactive material.

The fuel handling accident analysis inside containment assumes both of the personnel airlock doors are open and an additional 12" diameter penetration (or equivalent area) is open.

The analysis is bounded by these assumptions since all of the available activity is released within a 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months period.

The purpose of the current requirement to have one containment PAL door closed during core alterations and fuel movement is to restrict the escape of radioactive material in the event of a Fuel llandling Accident. This assumption is redected in the analysis for this accident as documented in the Seabrook UFSAR, Section 15.7.4, " Fuel 11andling Accident" A new Fuel llandling Accident analysis was performed which does not assume that the contaiunent PAL doors are closed at the time of the accident.

The offsite dose results of this new analysis are well within the limits of 10 CFR Part 100, as described in Standard Review Plan Section 15.7.4, Revision 1. The analysis results in a maximum offsite dose of 62.7 Rem to the thyroid and 2.0 Rem to the whole body with no credit for isolation. Calculated 30 day control room doses are 6.7 Rem to the thyroid and 0.29 Rem to the whole body and are within the acceptance limit of 5 Rem whole body, or equivalent organ dose of GDC 19. The assumptions and results of the evaluation are included in Attachment 1. The requirements of the Limiting Condition for Operation (LCO) 3.9.10, " Water Level - Reactor Vessel", and the minimum decay time of 100 hours0.00116 days 0.0278 hours 1.653439e-4 weeks 3.805e-5 months prior to core alterations (LCO 3.9.3, Decay Time) ensure that the release of fission product radioactivity, subsequent to a fuel handling accident, results in doses that are well within the acceptance limits specified in 10 CFR Part 100.

Actual ofTsite and control room doses in the event of a Fuel Handling Accident will be less because the PAL door will be closed following evacuation of the containment. The revised analysis assumes that the release continues for a full 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months and that all of the source term is released to the environment in that time. Therefore, the analysis assumes that the airlock can remain open indefinitely and that there is no credit taken for closing the doors. Requiring that a designated individual to be available outside of the airlock area to close the door following evacuation of the containment will minimize the release of radioactive material. The position of the 12" diameter penetration proposed in change 1 does not affect the offsite dose calculation for this change because all of the source term is assumed to be released through the personnel airlock.

The current Fuel llandling Accident analysis (UFSAR Section 15.7.4) in containment assumes no ofTsite dose because the containment is closed.

The dose remains well below the 10 CFR Part 100 limits and its overall significance will be offset by the decreased potential radiation dose to workers in the event of a Fuel Handling Accident, and the increased reliability of the PAL doors in the event of an accident.

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ased on the above, the proposed changes to Technical Specification 3.9.4, Surveillance Requirement 4.9.4 and their Bases have been shown to not significantly impact the probability or consequences of an accident previously analyzed. ;

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fL ,, klarkun of Proposed Channes l See attached markup of proposed changes to Technical Specifications. . The attached markup reflects the currently issued revision ofTechnical Specifications. Pending Technical Specifications ;

or Technical Specification changes issued subsequent to this submittal are not reflected in the enclosed markup.

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