ML20091D569

License Amend Request 91-08 to License NPF-86,improving PORV & Overpressure Protection Sys Availability,Per Generic Ltr 90-06, Resolution of Generic Issue 70 'Porv & Block Valve Reliability' & Generic Issue 94,'Addl....'

ML20091D569
Person / Time
Site:	Seabrook
Issue date:	10/16/1991
From:	Feigenbaum T PUBLIC SERVICE CO. OF NEW HAMPSHIRE
To:
Shared Package
ML20091D568	List: ML20091D565 ML20091D569 ML20091D571
References
REF-GTECI-070, REF-GTECI-094, REF-GTECI-NI, TASK-070, TASK-094, TASK-70, TASK-94, TASK-OR GL-90-06, GL-90-6, NUDOCS 9110250081
Download: ML20091D569 (6)

Text

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.' SEABROOK STATION UNIT 1

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New Hampshiro Yankee Facility Operating License NPF-80 Docket N. o. 50-443 ,

License Amendment Request No. 91-08 Improvements in PORV and Overpressure Protection System Availability,

-Generic Letter 90-06 This License Amendment Request is submitted by New Hampshire Yankee pursuant to 10 CFR50.90. The following information is enclosed in support of this License Amendment Request:

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. Section 1 - Introduction and Description of Proposed Changes

. Section 11 - Markup of Proposed Changes

. Section ll1 - Retype of Proposed Changes

.Section IV - Safety Evaluation of Proposed Changes

.Section V - Determination of Significant Hararris for Proposed Changes

.Section VI - Proposed Schedule for License Amendrnent issuanco and Effectiveness

. Section Vil -

Other Supporting Documentation l

Sworn and Subscribed to before me his

/% day of C 66tbra ) .1991. f. p l b b f$'6hMW M4/ /2 N/N//[N[) _ Ted C. Folg/nbaum Notary Public President and Chief Executive Officer inC/ A DMC C3 ettj rde t& con m.mn Layw;, L;wu J,1;%

9110250081 911o16 PDR ADOCK ODOon443 P PDR -- - _., -- ,_ ._.

l. Introduction and Description of Proposed chances A. Introduction The purpose of the proposed Technical Specification changes is to revise Specification I 3/4.4.4 ' Relief Valves' and its associated llases and Specification 3/4.4.9.3 ' Overpressure Protection Systems' to adhess the recommendations of USNRC Generic Letter (GL) 90 06, Resolution of Generic issue 70. ' Power Onernted Relief Valve and Block Valve Reliability."

and Generic issue 44. ' Additional Low Temnitature r Overnressure Protection for iinhe Water Renetors'.

" On June 25, 1990, the NRC issued GL 90 06 to advise pressurized water reactor licensees of the Staff's position resulting from the resolution of Generic lasues (Ols) 70 and 94. On the basis of technical studies for Gis 70 and 94, the Staff required that the actions in the Generic Letter (including changes to Technical Specifications) te taken by licent,ees that use or could use powereoperated relief valves (PORVs) to perform safety related functions.

New if ampshire Yankea responded to GL 90-06 on December 21,1990 (Ref NYN 90217 enclosed in Section' Vil). The N!!Y response to GL 90 06 describes NiiY'a complian:e with the hardware related and OA program related requirement 4 on PORVs and block valves. Additionally, the NHY-- response committed to submit the Technical. Specification changes required by GL 90-06. GL 90 06 included snodel Technical Specific.itsuns for Westinghouac, CE and B&W. plants utilizing.two or thice PORW The Technical Specification models, however, did not provide for the use of Residual Heat ,

Removal System suction relief valves for overpressure protectk,n, Therefore, a group of seven utilities formed to . develop a common approach to GL 40-06. Eight plants be affected by this effort. including: Calla vay, .Vogtle, Comanche Peak, htillstcc 3, Wolf .

Creek,.Byrou, Braidwcod, and Seabrook. This group was formed due to the lack ut specific _

guidance in GL 90 06 and a model Technical Sp,:cification for plants that have the . ability to use either the PORVs or the Residual I! cal Removal (RHR) suction relief valves for low temperature overpressure protection. A joint effort was possible due to the similarity of plant types and existing Technical . Specifications. All the plants are -Westinghouse piessurized water reactors which utilize the PORVs and RHR suction rdief valves for low-temperature overpressure protection. The generic letter wu reviewed by the group and a -

proposed Technical Specification developed that reflects the use of either the PORVs or the RHR suction relief valves or a combination thereof.

B. Description of. Proposed Changes The proposed Technical Specifications changes are consistent with- GL 90 06, GL 90 06 necessitates changes to Seabrook Station Technical Specification 3/4.4.4 " Relief Valves" and its associated Bases and Technical Specification 3/4.4.9.3 " Overpressure Protection Systems

• and its associated Bases. :The changes to Technical _ Specification 3/4.4.4 are intended to enhance the availability of the PORVs for RCS transient. mitigation. By maintaining power .

to closed block valves when the PORVs arc exhibiting excessive seat leakage, the block valves can be readily opened to afford use of the PORVs in mitigating a transient, if the block valve (s) are inoperable, the revised ACTION d. provides adequate measures to assure that a PORY will not become stuck open when a block valve is inoperable yet maintains the ability to use the PORVs for transient mitigation.

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a The changes to Technical Specificatian 3/4.4.9.3 provide enhanced operational flexibility ,

through the use of a PORV in combination with an RilR suction relief valve for low ]

temperature overpressurization protection. Each of these relief valves, alone is capable of mitigating a design basis -mass or heat addition transient. The revisions to ACTION b. ,

reduce the allowed outage time for one of the two required overpeessure protection devices l from 7 days to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> when in MODE 5 or 9, because the NRC has determined that the l potential for an overpressure 9ansient is highest in these MODES.  ;

i Technical Specification 3/4 4.4 and Associated Huses: ' Relief Valves

• j The proposed changes to Technical Specification 3/4.4.4 requested by OL 90 06 are described below:

1. The Limiting Condition for Operation (LCO) statement is being clarified by replacing

'All' with "Both" as the Seabrook design includes two PORVs.

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2. ACTION a. _is being revised to include the requirement to maintain power to closed block valve (s) because removal of power would render the block valve (s) Inoperable and the requirements of ACTION d. would apply. Power is maintained to the block j valve (s) so that it is operable and may be subsequently opened to allow the PORV to be - used to control- Reactor Coolant System (RCS) pressure. Closure of the block valve (s) establishes RCS pressure boundary integrity for a PORV that is exhibiting excessive seat ~ leakage. RCS pressure boundary integrity takes priority over the carability of the PORV to mitigate an overpressure event. The NRC noted in OL 90-06 that operation with the block valve (s) closed with power maintained to the block valve (s) is only intended to permit operation of the plant for a limited period of time not to exceed the next refueling outage so that maintenance can be performed on the PORVs to eliminate the seat leakage condition. .

. 3. ACTIONS a., b., and c. are being revised to eliminate the requirement to take the plant to COLD SilUTDOWN. This revision is being msde because the APPLICAlllLITY requirements of the LCO do not extend past the HOT STANDBY MODE.

4. ACTION c. is ' being revised to provide consisteney with ACTION b. Curre ntly, ACTION c. requires that with two inoperable PORVs, due to causes other than excessive seat leakage, both PORVs must be restored to OPERABLE status within one hour or a shutdown must be commenced. Currently, ACTION c. does not credit the restoration of one PORV to OPERABLE status within one hour. If one PORY is restored to a OPERABLE status within one hour, the requirements of ACTION b.

should apply which provides 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to restore an inoperable PCRV.

I 5. ACTION d. is being revised to establish remedial measures that are consistent with the function of the block valves. The primary function of the block valves is the isolation of a stuck open PORV. If the block valve (s) cannot be restored to operable status within I hour, the remedial action is to place the PORV in manual control (i.e.

the control e xitch in the *CLOSE" position) to preclude its automatic opening for _an overpressure event and to avoid the potential for a stuck.open PORV at a time when ,

the block valve is inoperable. The time allowed to restore the block valve (s) to opciable status is the same as the remedial action time limits for inoperab% PORVs per ACTIONS b. and c since the PORVs are not capab.le of automatic mitigation of an overt.ressure event when placed in manual control. ACTION d. does not specify closure of the block valves as is required in ACTIONS b. and c. because such action may not be.possible when the block valve is inoperable. Likewise, ACTION d. does .

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not specify the closure of the PORV, because it would not likely be open, nor does -

it specify the removal of power from the PORV. When the block valve is inoperable, .

placing the PORV in manual control is sufficient to preclude the potential for having a stuck open PORV that could not be isolated because of an inoperable block valve.

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6. Surveillance Requirement 4.4.4.1.b has been revised to require that PORVs be cycled only during MODE 3 or 4. The NRC specified in OL 90-06 that stroke testing of the PORVs should not be performed duting power operation. GL 90 06 requires that the PORVs be cycled in MODE 3 and MODE 4 to simulate the temperature and environmental effects on the PORVs. t

7. The change to Bases page B 3/4 4 2 clasifies PORV operability requirements in MODE 1, 2 and 3. Technical Specification 3/4.4.4 requires that if one PORV is inoperable due to causes other than excessive seat leakage, within one hout the PORV must be restored to operable status or the associated block valve must be closed with its power removed. A PORV is considered inoper Nie if it is not capable of performint; its specified function. As noted in the Bases revision, no credit for automatic PORV operation is taken in the FSAR analysis for MODE 1, 2 and 3 transients, and the PORVs can be considered OPERABLE in either the manual or automatic mode. This clarification is added due to the potential situation where an automatic signal to the PORVs is inoperable, but the PORY is mechanically functional. Since the PORV is still mechanically functional, it is OPERABLE and therefore it is not necessary to close and remove power from the block valve. Thus the PORV remains in a condition where it can be manually opened from the control room if required. This clarification is consistent with the . OPERABILITY requirements for the PORVs in MODE 1, 2 and 3.

Icchnical Soccification 3/4.4.0.3 anu Associated Bases: 'Overotessute Protection Systems" '

The proposed changes to Technical Specification 3/4.4.9.3 are described below:

1, The LCO - statement is being modified to require that at least two overpressure protection devices must be OPERABLIL That is, two PORVs or two RilR suction relief valves or one PORV and one RilR suction relief valve must be operable when cold overpressure protection is required. The NRC found acceptable the use of the l RilR suction relief valves for low-tempcrature overpressure protection in NUREO-0896, ' Safety Evaluation Report related to the operation of Seabrook Station, Units 1 and 2*. Seabrook Station overpressure protection analyses demonstrate that cach RilR i

suction relief valve provides sufficient relicI capacity to prevent exceeding 10 CFR E Appendix G limits during the overpressuriration design bases mass addition event of one charging pump or one safety injection pump operating at full flow with the RCS water solid and loss of Ictdown capability. The analyses also show each RilR suction

- relief valve will prevent exceeding the Appendix 0 limits during the overpressurization design bases heat addition event of a reactor coolant pump start with the steam p

generator secondary temperature 50*F warmer than RCS temperature, it is also noteworthy that the NRC has issued License Amendment No. 3 allowing the deletion of the Residual lleat Removal System suction isolation valves autoclosure L interlock (ACI) function. NilY has implemented the RilR ACI deletion design change during the current refueling outage. This modification enhances RilR system reliability and overpressure protection system availability by precluding spurious RilR suction valve closures caused by potential malfunctions of the ACI circuit. The combination 3

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of PORVs and R11R suction relief valves provides an equivalent level of overpressure  ;

protection with no degradation in the level of safety. Added assurance of overpressure protection system availability is provided by reducing the AUT for an inoperable PORV  :

or RllR suction relief valve from 7 days to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> in MODE 5 and 6. The increased availibility of the overpressure protection system provides an increase in the overall protection of the public health and safety.

2. ACTION a. (as renumbered) is revised to clarify that it is only applicable in MODE 4 The allowed outage time (AUT) for an overpressure protection device in MODE r 5 and MODE 6 is proposed to be reduced as discussed below. ACTION a. is also .;

reformatted to facilitate use by the operators.  !

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3. A 1 TION b. is added to reduce the AOT for one of the two required overpcessure protction devices to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> in MODE ' S or 6. The NRC has considered the '

conditions under which a low temperature overpressure transient is most likely to occur.

While low temperature overpressure protection is required for all shutdown modes, the most vulnerable period of time was found to be MODE 5 with the reactor coolant temperature less than or equal to 200'F .cspecially when water solid, based on the- .

detailed evaluation of operating reactor experiences performed in support of Generic Issue 94. The NRC Staff concluded that the low temperature overpressure protection ,

system performs a safety related function' and inoperable overpressure - protection equipment should be restored to an operable status in a shorter period of time. The ,

f current 7 day AOT is considered by the NRC to be too long under certain conditions, The NRC has concluded that the AUT should be reduced to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> when operating MODE 5 or 6 when the potential for an overpressure transient is highest.

4. ACTION c. (as renumbered) is reformatted to facilitate use by the operators.

5. Surveillance Requirement 4,4.9.3.1 is revised pursuant to GL 90 06 to simplify the Surveillance Requirement by " removing requirements that exist because of the general requirements applicable to all surveillance requirements as specified in Section 4.0 of the Technical Specificatio_ns.' Technical Specification 4.0.4 has the effect of requiring that the ANALOG CHANNEL OPERATIONAL TEST (ACOT) required by Surveillance Requirement 4,4.9.3.1 be performed before the PORV is deemed OPERAlhE for cold overpressure protection, it is not necessary that the surveillance explicitly state that the ACOT is required within 31 days prior to entering a condition in which the PORV is required OPERABLE. Additionally, Surveillance Requirement 4.4.9.3.1 has been revised for consistency with Surveillance Requirements 4.4.9.3.2 and 4.4.9.3.3. -

6. The change 'to Bases page B 3/4 415 allows for the combination of a PORV and R11R suction relief valve for RCS cold overpressure protection, consistent with the changes to Technical Specification 3/4.4.9.3.

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!!, hin:Lun o/ Propored Chnnen See attached matkup of proposed changes to Techuical Specifications.

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