ML20151D286

Safety Evaluation Supporting Amends 69 & 61 to Licenses DPR-77 & DPR-79,respectively

ML20151D286
Person / Time
Site:	Sequoyah
Issue date:	04/04/1988
From:	NRC OFFICE OF SPECIAL PROJECTS
To:
Shared Package
ML20151D281	List: ML20151D286
References
NUDOCS 8804140101
Download: ML20151D286 (3)

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0 UNITED STATES

!) 3 s., { h NUCLEAR REGULATORY COMMISSION l

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a f.j SAFETY EVALUATION BY THE OFFICE OF SPECIAL PROJECTS h

SUPPORTING AMENCMENT NO. 69 TO FACILITY OPERATING LICENSE NO. OPR-77 q

AND AFFNOMENT NO. 61 TO FACILITY OPERATING LICENSE N0. DPR-79 h

TENNESSEE VALLEY AUTHORITY g

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SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 i:

DOCKET NOS. 50-327 AND 50-328 f

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1.0 INTRODUCTION

f By letter dated April 8,1987, Tennessee Valley Authority (TVA), submitted a l

proposed change to the Technical Specifications (TS) for Sequoyah, Units 1 and 2.

The proposed change to Section 3/4.6.2 would specifically require the operability of residual heat removal (RHR) spray and clearly specify the surveillance requirements for both the RHR and containment spray trains. The E

applicability statement would be revised to exempt the operability require-

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ments for RHR spray in Mode 4 (hot shutdown).

In addition, two minor typographical d

errors in the Unit 1 TS would be corrected.

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2.0 DISCUSSION L

The spray system at each unit of Sequoyah has four headers; two of these are used for containment spray (each with a dedicated pump and heat exchanger) which is automatically initiated on high-high containment pressure. The other two headers are for the RHR spray system; this system is initiated by l

manual valve manipulations. The RHR system is an emergency core cooling systen (ECCS) and is also used for shutdown docay heat removal in Modes 4 u

and 5.

As discussed in the Final Safety Analysis Report (FSAR), one train i.

of RHR spray is needed to mitigate a loss-of-coolant accident (LOCA) if only b

one train of containment spray)is available. TS 3.5.2 requires operability of both trains of RHR (as an ECCS during Modes 1, 2 and 3.

TS also address RHR l,

h requirements for decay heat removal in Modes 4, 5 and 6.

Operability of the contair. ment spray system is required for Modes 1 through 4 by TS 3.6.2.1.

l However, specific requirements on the RHR spray are not identified in the TS.

TVA proposes to subdivide TS 3.6.2.1 to address containment spray and RHR spray l

cyplicitly.

3.0 EVALUATION P

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The revised limiting condition for operation for TS 3.6.2.1 would require two R

independent trains of both containment spray and RHR spray and defines what p

a train consists of.

In particular, a train comprises an CPERABLE purp, an 3

OPERABLE heat exchanger and an OPEPABLE flow path.

The containment spray flew h

path must be capai,le of suction from the refueling water storage tank and then from the sump; the RHR spray path is from the sump only. These requirer'ents are consistent with necessary functions of these system as discussed in the 7

safety analysis. The action statement for an inoperable RHR spray train or a y

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containment spray train would remain as presently in the TS. A surveillance requirement for RHR spray train is added.

The type and frequency of testing

?j of the RHR spray is consistent with that required for other RHR (ECCS) and j

containment spray trains.

Thereford, the staff finds these TS changes acceptable.

TVA also proposes that operability of the RHR spray trains not be recuired for 3

Mode 4 The basis for this is discussed below.

General Operating Instruction (G01)-3, "Plant Shutdown from Minimum Lead to Cold Shutdown," stipulates a cooldown rate of 50'F per hour. Thus, it would q

take four hours to get from a shutdown from normal temperature (Mode 1) to Mode 4 The Function Restoration Guidelines, which establish the basis for 0

emergency operating instructions, proHbit the use of RHR spray for at least one hour after initiation of a 1.0CA.

Thus, the earliest time that RHR spray could be called upon following plant shutdown for a LOCA in Mode 4 would be 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />. At that time, the decay heat rate is only 61% of the decay heat rate at I hour.

Since a containrent spray train alnne has 70% of the capacity of the combined ficw of one containment spray train and one RHR spray train, the RHR spray train would not be needed.

Further, the blowdown energy released to containment for a LOCA in Mode 4 would be significantly less than for a design basis LOCA from full power and terperature. Therefore, +.he staff concludes that operability of RHR spray is not required in Mode 4 ard that the proposed TS are acceptable.

n energency operating procedure (FR-Z.1) posed charge, the staff reviewed the In the course of our review of this pro associated with operation of RHR spray.

The procedures do not clearly addrefs the situation when only one RHR purp is operable ard providing flow to both the safety injection pump suction and to the RHR spray header. The staff believes that n part of your implementation of this TS change. TVA should clarify the procedures regarding verification of proper flow balance.

4.0 ENVIRONMENTAL CONSIDERATION

These amendments involve a change to a requirerent with respect to the (3

installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes to the surveillance requirements. The staff has detennined that the amendments invclve no significant increase in the arounts, and no significant change in the types, of any effluents that ray be released offsite, and that there is no significant increase in indivic'ual or cumulative occupational radiation exposure. The Comission has previously issued a proposed finding that these amendments involve no significant ha:ards consideration and there has been no public corrent on such finding, Accordingly, 3

the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).

Pursuant to 10 CFR 51.2C(b), no environmental inpact statement ror envircrrental assessnent need be prepared in connecticn with the issuance of these amendments, i

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5.0 CONCLUSION

4j We have concluded, based on the considerations discussed above, that:

(1) there is reasonable assurance that the health and safety of the public 3

l will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance wit:1 the Comission's regulations, y!

and the issuance of the amendnnts will not be inimical to the comon defense and security nor to the health and safett of the public.

Principal Contributor:

E. McKenna l

Dated:

April 4. 1988

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