ML18029A390

Proposed Tech Specs Deleting Refs to RHR Sys inter-unit Crosstie Capability

ML18029A390
Person / Time
Site:	Browns Ferry
Issue date:	02/25/1985
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML18029A389	List: ML18029A388 ML18029A390
References
NUDOCS 8503040278
Download: ML18029A390 (23)

Text

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I.IHITIHG COtlOLTLOHS FOR OPKRATIOH BURURILLLec~ RKIRUIRRIRRP'i 3,5.8 ResIdual Heat Ree(oval S ste(s

~RHRS (LPC( and Centainnent Cooling)

B.S,B R-. I leal

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~RIIR" (LPCI and Cnntitnn nt Cool inp)

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LIMITING CONDITlONS FOR OPERATION SURVEILLANCE RE UIREHENTS 13.

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. DELETED 14.

All recirculation pump discharge valves shall be operable prior to reactor startup {or closed if permitted elsewhere in these specifications).

All recirculation pump'ischarge valves shall be tested for operability

, during any period nf reactor cold shutdown exceeding 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. if operability tests have not been performed during the preceding 31 days.

150

3

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PA SRS r

Should onc lrllR pump (cnntsinmcnt cooling modr ) brea m.. lnnparsble, a com-p)cmrnt of chrcc full capacity concsfnrncnt heat removal rrystc'ms is still rrvailablc.

Any tvo of the rcnraining prrmps/hcnt exchanger comb)nations would provide morc than adequate containment cooling. for any abnormal or post accident situation.

Because of thc availability of equipment in access oE normal redundancy requirements, which is demonstrated to be operable. immediately and with specified subsequent perfonnance, a 30-day repair period is )ustified.

Should two RHR pumps (containmcnt cooling mode) become inoperable, a Eull liest removal sysccm is still availablc.

The remaining pump/heat exchanger combinations would provide adequate containment cooling for any abnormal poet accident situation.

Because of the availability of a Eull cornplemcnc of heatr removal equiprncnt, yhicIr is demonstrated to be operable immediately and wich sl~ccified performance, a 7-day repair period is )ustified.

I (observation of thc stated requirements for the containment cooling mode assures that chc suppression pool and the drywcll will bc sufficiently

cooled, following o; loss-of-coolant accident, to prevent primary contain-m'cnt ovcrrpreosurisation.

Thc containrncnc cooling function of the RHRS is permit;tcd orrly after the core has ref loodcd co thc cwo-thirds core hciyht lcvcl.

This prevents inadvertently diverting wrccr necdcd for core flooding to the less urgent task of contsinrncnt cooling.

The two-thirds cote height level interlock may be manually bypassed by a keylock switch.

Since the RHRS is filled with lov quality water during power operation, it is planned that the system be filled vith demineralited (condensate) water before using She shutdovn cooli'ng function of the RHR system.

Since it ie desirable to have the RHRS in service if a "pipe-break" type qf accident should occur, it is permitted to be out oE operation Eor only a restricted amount of'.time and vhen the system'ressure is lov.

At least one-half of the containment cooling function must remain operable during this time per)ed.

Requiring tvo operable CSS pumps during cooldown alloys for flushing the RHRS even if the shutdown vere caused by inability to meet the CSS specifications (3.5.A) on a number of operable pumps.

Mhen the reactor vessel pressure is atmospheric, the limiting conditions for operation arc less restrictive.

Ac atmospheric

pressure, thc minimum rcquircmenf is for onc supply of makeup water to the core.

Rcqui.ring cwo opernblc RHR pumps and onc CSS pump provides redundancy co ensure makeup

(

water availab'ility.

161

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REFERENCES 1.

Residual Heat Removal System.(BFHP FSAR subsection 4.8) 2.

C<<re Stan<)by Cooling Systems (BFHP t

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3. n.C RER Sc v<c" r~leacr S "e n ane

<Cnev ecc FSAR Section 6)

E< hinmont Coo< in! !"ater "vne'c<<<

(El:CWS)

There are two EECW headers (north and south) with four automatic starting RHRSW pumps on each header.

All components requiring emergency cooling water are fed from botg headers thus assuring continuity of operation if either header is operable.

Each header alone can handle. the flows to all t components.

Two RHRSW pumps can supply the full flow requirements of all essential EECW loads for any abnormal or postaccident situation.

There are four RHR heat exchanger headers (A, B, C, 6 D) with one RHR heat exchanger from each unit on each header, There are two RHRSW pumps on each header; one normally assigned to each header (A2, B2, C2, or D2) and one on alternate'ssignment (Al, Bl, Cl, or Dl),

One RHR heat exchanger header can adequately deliver the flow supplied by both RHRSW pumps to any two of thy three RHRSW heat exchangers on the header.

< One RHRSW pump can "supply the full flow requirement of one RHR heat exchanger.

Two RHR heat exchangers can more than radequately handle'the cooling requirements of one unit in any abnormal or postaccident situation, 1

The RHR Service Water Systems was designed as a shared system for three

units, The specification, as written, is conservative when consideration is given 'to particular pumps being out of service and to possible valving arrangements.

If unusual operating conditions arise such that more pumps are out of service than allowed by this specification, a special case request may be made to the NRC to allow continued operation if the actual system cooling 'r'equirements can be assured.

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Snoqld onc of the,two RHRSW pumps normally cr alternately assigned to the RHR heat exchanger header su'pplying the standby coolant supply connection become inoperable, an equal capability'or long-term fluid makeup to the unit reactor sad for cooling of the unit containment remains operable.

Because of the availability of an equal makeup and cooling capability which is demonstrated to be operable immediately and with specified subsequent surveillance, a 30-day repu'<r period is Justig.ed.

Should the capability to provide standby coolant supply be lost, a 10-day repair time is )ustified based on the low probability for ever needi'ng the standby coolant supply.

I 164

UNIT 2 PROPOSED SPECIFICATIONS 3'

LIHITIHC COHDLTIOHS FOR OPERhTIOH SURVEILLANCE UIREHFHTS r

3.S.B Reeidual Heat Removal Svstaa

~RHRS (LPC( and Cancadnncnc Cooling) 0 ~ 5 ~ B Reai(lual float Roll(RPVa I,CVIP ) ".III

'IUIRS (LPCI and Cnncacancnc Cooling) n, 12.

149

LIMITING CONDITIONS FOR OPERATION SURVEILlANCE RE UIREMENTS 13.

13.

14.

Al 1 recirculation pump discharge valves shall be operable prior to reactor startup (or closed if permitted elsewhere in these specifications).

14. All recirculation 'pump discharqe valves shall be tested for operability during any period of reactor cold shutdown exceeding 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, if operability tests have not been performed during the preceding 31 days.'5O

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AASVS Sl>ou]d nnc IIIIR pump (<nntainmcnt coolIng L'ode) bccnm" Inoperable, o corn-plcmrnt of three full capacity concsfnmcnc hest remnval syscc'mo ts still svailablc.

Any Cwo o t

e rema n

i. I l A

f ch

. remaining pumps/hcnt exchanger combinations cauld provide note chan adequate containmcnt cooling for any abnormal or post accident situation.

Because of thc availability of equipmcnc n

'access of normal redundancy requirements, which is demonstrated to be operable immediately and with specified subsequent performance, a

3 - ay

~ repair period is )ustified.

Should two RHR pumps (containment cooling mode) become inoperable, a full

'eat removal system io still available.

The remaining pump/heat exchanper combiner;ions would provide adequate containment cooling for any abnormal post sccFctent situation.

Because of the availability of a full complement of heat removal equipmcnt, which is demonstrated to be operable immediately and with specified performance, a 7-day repair period is 5ustificd.

(bocrvation of thc stated requirements for the containment cooling mode assures chat the suppression pool and the drywcil will be sufficiently

cooled, following o loss-af-coolant

accident, to prevent primary contain-ment ovcrpressurirotion.

Thc conteinmcnc cooling function of the RHRS is permitted only after the core hns ref loodcd to thc two-cbirds core height lcvcl.

This prevents inadvertently divertinp water needed for core flooding to the less urgent task of containment cooling.

The two-thir'ds core height level interlock may be manually bypassed by a keylock switch.

Since the RHRS is filled with Iow quality water during power operation, it is planned that the system~be filled with demineralized (condensate) wacer before using the shutdown cooli'ng function of the RHR system.

Since it is desirable to have the RHRS in service if a "pipe-break" type of accident should occur, it is permitted to be out of operation for only a restricted amount of time and when the system pressure is law.

ht least one-half of the containment cooling function must rema'perable during this time period.

Requiring two operable CSS pumps during cooldown allaws for flush ng the RHRS even if the shutdown were caused by inability to meet the CSS specifications (3.5.h) on a number of operable pumps.

Mhen the reactor vessel pressure is atmospheric, the limiting conditions for operation are less restrictive.

At acmosphcxic

pressure, the minimum rcquircmenc is for onc supply of makeup wacer to the core.

Requiring two operable RHR pumps and onc CSS pump provides redundancy to ensure makeup water availability.

161

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~3.,

BASES REFEHEiaCES l.

Residual Heat..Removal System (BFHP FSAR subscct,ion 4<<8) 2.

CIBre Standby Cooling Syst.ebs (BFliP FSAR Section 6) 3.'!'.C RIIR Sa.ata" I~IetCr S "te:a ana Ieger en<<V E <<tenant Caa!In:

': <<tar.'."V::I:!.a (I'I'.C'v:. )

There are two KECK headers (north and south) with four automatic starting RHRSW pumps on each header.

All components requiring emergency cooling water are fed from both 'headers thus assuring continuity of operation if either header is operable.

Each header alone can handle the flows to all components.

Two RHRSW pumps can supply 'the full flow requirements of all essenti,al EECW loads for any abnormal or postacci,dent situation.

There are four RHR heat exchanger headers (A, B, C,

6 D) with one RHR heat exchanger from each unit on each header.

There are two RHRSW pumps on each header; one normally assigned to each header (A2, B2, C2, or D2) and one on alternate assignment (Al, Bl, Cl, or Dl).

One RHR heat exchanger header can adequately deliver the flow supplied by both RHRSW pumps to any two of the three RHRSW heat exchangers on ther header.

One RHRSW pump can supply the full flow requirement of one RHR heat exchanger.

Two RHR heat exchangers can more than adequately handle the cobling requirements of one unit in any abnormal or postaccident situation.

4 The RHR Service Water Systems was designed as a shared system for three units.

The specification, as written, is cohservative when consideration I

is given to particular pumps being out of service and to possible valving arrangements.

Zf unusual operating conditions arise such that more pumps are out of service than allowed by this specification, a special case request may be made to the NRC to allow continued operation if the actual system cooling requirements can be assured.

Should three of the four RHRSW pumps normally cr alternately assigned to the RHR heat exchanger headers

. supplying the standby coolant supply connection become inoperable, capability for long-term fluid makeup to the unit reacto:

and for cooling of thc unit containment remains operable.

Because of'he 1

availab'lity of

makeup and cooling capability which is demonstrated to bc operable,immediately and with specified subsequent surveillance' 3p-d y 3 cpa'.r period fs Just.ified.

Unit 2 may bc supplied standby oolant from either of four pumps M, 9:!, Dl, nr D2.

Should the capability to provide standby coolant supply be lost, a 10-day repair time is )ustified based on the low nrobability for ever needing the standby coolant supply.

164

UNIT 3 PROPOSED SPECIFICATIONS

LtHITING CONDITIONS FOR'PERATION SURVEILLANCE REQUIREMENTS 3 ~ '5 CORE AND CONTAINMENT COOLING SYSTEMS 4 ~ 5 CORE AND CONTAINMENT COOLING SYSTEMS 8.

If specifications 3.5.B.1 through 3.5.B.7 are not met,

" an orderly shutdown shall be initiated and~the reactor shall be shutdown and placed in the cold condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

9.

-when the reactor vessel pressure is atmospheric and irradiated fuel. is in the reactor vessel at least one RHR loop with two pumps or two loops with one pump per loop shall be operable.

The pumps I associated diesel generators must also be operable.

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10. If the conditions of specification 3.5.A.5 aie'et, LPCI and containment cooling are not required.

8 ~

9.

10, second operable access path for the same phase of the mode (drywell sprays,'uppression chamber sprays and suppression pool cooling) shall be demonstrated to be operable daily thereafter until the second path is returned to normal service.

No additional surveillance requir ed.

When the reactor vessel pressure is atmospheric, the RHR pumps and valves that are required to be operable shall be demon>>

strated to be operable monthly.

No additional surveillance required.

153

0 t

I LIMITING CONDITIONS FOR OPERATION

'URVEILLANCE REQUIREMENTS

=

1 ~ 5 CORE AND COPPAINMENT COOL'I:iG SYSTEMS 0'

CORE AND CONTAINMENT COOLIN SYSTEMS j

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13.

l3o 14.

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All recirculatiqn pump discharge valves shall be operable prior to reactor startup (or closed if permitted elsewhere in these Specifications).

ity exceeding 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, if operability tests have not been performed during the preceeding 31 days.

14.

All recirculation pum disc harge valves shal be tested for operabil during any period of reactor cold shutdown

J, 5 f)hf>Ei b'av~

th>> PllRS xn service if a "pipe-break" type of accident uh~iuld occur, it is permitted to be out of operation for only restricted amount of time and when the system pressure is low.

At least one-half of the containment cooling function must remain operable during this time period.

Requiring two operable CSS pumps during cooldown allows for flushing the RHRS even if the shutdown were caused by inability to meet the CSS specifications t3. 5.A) on a number of operable pumps.

Qhen the reactor vessel pressure is atmospheric, the limitinq conditions for operation are less restrictive.

At atmospheric

pressure, the niinimum requirement is for one

.supply of makeup water to the core.

Requiring two operable

'RHR pumps and one CSS pump provides redundancy to ensure makeup water availability.

. k'&ttaIX.""Ci~f~

t The suppression chamber can be drained when the reactor vessel pressure is atmospheric, irradiated fuel is in the reactor vessel, and'work is not in progress which has the potential to drain the vessel.

By requiring 4he fuel pool gate (o be open with the vessel head

removed, the combined water inventory in the fuel pool, the rqacgor cavity, and the separator/dryer pool, between the fuel pool low level alarm and the reactor vessel flange, is about 65,800 cubic feet (492,000 gallons).

This will provide adequate low-pressure cooling in lieu of CSS and RHR (LPCZ and containment cooling mode) as currently required in specifications 3.5.A.4 and 3.5.B.9.

The additional requirements for provididng standby coolant supply available will ensure a redundant supply of coolant supply.

Control rod drive maintenance may continue during this period provided no more than one drive is removed at a time unless blind flanges are installed during the period of time CRD' are not in place.

170

ENCLOSURE 2 Descri tion DESCRIPTION AND JUSTIFICATION AND SAFETY ANALYSIS (TVA BFNP TS 207)

Pages

149, 150,

161, and 164 for units 1 and 2 and pages

153, 154, and 170 for unit 3 are being changed to delete sections 3.5.B.11, 4.5.B.11, 3.5.B.12, 4.5.B.12, 3.5.B.13, 4.5.B.13, and the associated bases.

These sections specify operabili'ty and surveillance requirements for the RHR interunit crosstie capability.

Justification The RHR crosstie capability at Browns Ferry allows each unit access to one RHR loop (2 pumps and 2 heat exchangers) belonging to its physically adjacent unit~

by providing both suction and discharge piping between units.

Current limiting conditions for operation associated with this feature prohibit ma)or outage modification and maintenance work on RHR loops in some cases without requiring operating two units to be placed in cold shutdown.

The existence o

technical specifictaion limiting conditions for operation covering this type of plant feature is overly restrictive and not typical of other BWRs.

Safet Anal sis The RHR crosstie and standby coolant supply features, as described in FSAR section 4.8.6.4, provide added long-term redundancy to other emergency core and containment cooling systems and are designed to accommodate certain unlikely situations which could Jeopardize these systems.

The RHR unit crosstie is not part of the safety design basis for the RHR system stated in section 4.8.3 of the FSAR.

The RHR service water crosstie (standby coolant supply) is included in the safety design basis and is not affected by this proposed amendment.

No credit is taken for the RHR crosstie feature in design basis accident analyses; and therefore, its elimination as a technical specification requirement does not reduce any analyzed safety margin. It should be noted that the RHR crosstie feature is not being eliminated from the plant design.

't will continue to be maintained in the same manner as other design features, t which are described in the FSAR and provide additional plant safety but are not part of the safety design basis or technical speoifications.

ENCLOSURE 3

PROPOSED NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION (TVA BFNP TS 207)

The Commission has provided guidance concerning the application of the standards in 10 CFR 50.92 by providing certain examples (48 FR 14870, April 6, 1983).

One of the examples (vi) of actions not likely to involve a significant hazards consideration relates to change which either may result in some increase in the probability or consequences of a previously analyzed accident or may reduce in some way a safety margin, but where the results of the change're clearly within all acceptable criteria with respect to the system or component specified in the Standard Review Plan.

The proposed changes remove limiting conditions for operation for the RHR crosstie

'capability.

This capability is not required by Standard Technical Specifications (NUREG-0123) or the Standard Review Plan.

The featur e itself is not being removed from the plant design.

Therefore,~ since the changes are within the Standard Review Plan, TVA propos>,

to determine that the proposed changes would not involve a significant hazar cdnsideration determination in that they:

(1) do not involve a significant increase in the probability or consequences of a previously evaluated accident; (2) do not create the possibility of a new or different kind of accident from any accident previously evaluated; and (3) do not involve a significant reduction in a margin of safety.

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