AECM-86-0052, Application for Amend to License NPF-29,changing Tech Specs to Lower Requirement for Standby Gas Treatment Sys Heaters in Surveillance 4.6.6.3.d.5 to 50 Plus/Minus 5 Kw

Application for Amend to License NPF-29,changing Tech Specs to Lower Requirement for Standby Gas Treatment Sys Heaters in Surveillance 4.6.6.3.d.5 to 50 Plus/Minus 5 Kw

ML20141G127
Person / Time
Site:	Grand Gulf
Issue date:	02/17/1986
From:	Kingsley O MISSISSIPPI POWER & LIGHT CO.
To:
Shared Package
ML20141G088	List: AECM-86-0052, Application for Amend to License NPF-29,changing Tech Specs to Lower Requirement for Standby Gas Treatment Sys Heaters in Surveillance 4.6.6.3.d.5 to 50 Plus/Minus 5 Kw L-86-002, Forwards Application for Amend to License NPF-29,changing Tech Specs to Lower Requirement for Standby Gas Treatment Sys Heaters in Surveillance 4.6.6.3.d.5 Per NUREG-0588.Fee Paid ML20141G084 ML20141G173
References
AECM-86-0052, AECM-86-52, TAC-60700, NUDOCS 8602260167
Download: ML20141G127 (4)

Text

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BEFORE THE UNITED STATES NUCLEAR REGULATORY COMMISSION LICENSE NO. NPF-29 DOCKET No. 50-416 IN THE MATTER OF MISSISSIPPI POWER & LIGHT COMPANY and MIDDLE SOUTH ENERGY, INC.

and SOUTH MISSISSIPPI ELECTRIC POWER ASSOCIATION AFFIRMATION I, O. D. Kingsley, Jr., being duly sworn, stated that I am Vice President, Nuclear Operations of Mississippi Power & Light Company; that on behalf of Mississippi Power & Light Company, Middle South Energy, Inc., and South Mississippi Electric Power Association I am authorized by Mississippi Power & Light Company to sign and file with.the Nuclear Regulatory Commission, this application for' amendment of the Operating License of the Grand Gulf Nuclear Station; that I signed this application as Vice President, Nuclear Operations of Mississippi Power & Light Company; and that'the statements made and the matters set forth therein are true and correct to the t of my knowledge, information and belief.

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O. W./ king e-STATE OF MISSISSIPPI COUNTY OF HINDS SUBSCRIBED AND SWORN TO before me, a Notary Public, in and for the County and State above named, this /7//, day of Fe' 6 r y. u

, 1986.

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Att chment I to' 4

AECM-86/0052 l

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SUBJECT:

NPE-86/003-

- Technical Specification' Surveillance Requirement 4.6.6.3.d.5; K

.page 3/4-6-56" DISCUSSION:

Surveillance Requirement'4.6.6.3.d.5 requires that at least V'

once per 18 months the standby gas treatment: system heaters are

= verified to. dissipate 50 1-5.0 KW when tested in'accordance Mth ANSI N510-1975 :(except for"the phase balance criteria; stated'in'Section 14.2.3)..These1 heaters were tested in March 1985fand were found to dissipate greater than 45 KW.

Sa veillance Requirement 4.6'.6.3.d.5 was again performed,on

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February 15,.1986 for B Train. -The test results showed~a heat.

dissipatio'n of;1ess than145-KW, which-does'not meet the surveillance requirement.. As a result,.the,B Train;of the-standby'~ gas treatment' system was declared inoperable and entry into' Operational ~ Conditions'1,.2,t 3 and

• was prohibited..

MP&L is requesting by this proposed change that Surveillance.

Requirement 4.6.6.3.d.5.be revised to reflect a' heat-dissipation requirement of 48 SKW.-

JUSTIFICATION: The operability of the standby gas treatment systems within secondary' containment.' ensures that' sufficient iodine removal;

't carability will be available in-th'e eventL-of a LOCA.' 'The f[, l ireduction in containment iodineT nventory reduces.the.resulting i

J site boundary radiation doses associated with containment leakage. The operation of this: system and resultant iodine removal capacity are consistent with the assumptions used in i

the LOCA analyses. Continuous' operation of-the system with thei heaten/ operable for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> over a 31-day 1 period is' sufficient to rede'ce the buildup of moisture on-the-adsorbers and'HEPA-filters.

..The heaters originally ins *o 1.ad'in the standbyLgas treatment h

system were 50KW nominal W +.pplied by vendor CVI.- These-y heaters were not qua*1 % r the' requirements:of NUREG 0588 and s

were subsequently red.:.at'

,- March 1985 with 48 KW nominal'

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. heaters-supplied by. vendor Ellis and Watts that'were qualified..

The size;(50 KW nominal)'of the originally.' installed: heaters I

should not be-used as the basis for_the' heat dissipation requirement presently in Surveillance Requirement 4.6.6.3.d.5..

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The s' ire ~(48KW nominalc) of. the presently l installed heaters /

should be'used.to form the' basis forJthe value used;in;this o?

surveillance. For the SBCT system the'new. heaters'have'been-marginal when:trying to' comply with: Surveillance Req'uirement-4.6.6.3.d.5 to meet:50.i'.5 KW heat. dissipation.$ Alsmall' drop;in:

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' incoming line voltage can mean'theJdifference'in p'assingcor failing the; surveillance.

In' order to' solve this problem, MP&L 3

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has; performed a calculation-to' determine ~the minimum heat' dissipation.requiredffor'the SBGT system'in order'to meet ~ design; requirements. JAs explained;below, the: calculation demonstrates; that a minimumLof approximately 21.5 KW heat dissipation inteach

SBGT train will reduce the relative; humidity of the air leaving l

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the heaters to 70%..The proposed, change:to'48 i 5KW will ensure that design ~ conditions are met.;

The calculation to datermine needed heater' size for SBGT assumes;

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an incoming air temperature of.150'F with 100% relative humidity.

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and a SBGT system flowrate of 4500 CFM (4000 CFM required).>-The;

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heaterisize required to reduce.the relative-humidity offthe'

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air, leaving the-heaters;to 70% is approximately.21.5 KW.; The requirement to reduce-the' relative humidity from 100%.to'70%f under worstJease DBA conditions is.specified~in Regulatory. Guide'

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SIGNIFICANT HAZARDS CONSIDERATION:

The proposed change,to'the technical specifications reduces the-heat dissipation requirement of'the heaters in theLSBGT system from 50

~5 KW to 48 5 KW.

The 50 2 5 KW is based on.the heaters originally installed and.not on the heaters presently:

installed. Regulatory Guide-1.52~ Revision 1. requires"a heater sized to reduce the relative humidity of the incoming air from 100% to 70%.dur'ing postulated DBA conditions.'.The proposedy48-1.

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. 5~KU heat dissipation exceeds these design requirements since a-minimum of approximately 21.5 KW is all that is required'to':

ensure 70% relative humidityfair leaving the heaters.-

The proposed change does-not involve a significant increase in the probability or consequences of anJaccident.previously evaluated because the propos~ed change to a 48'i 5 KW

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meets the' design requirement to lower the~ relative humidity of-the incoming air from 100% to 70% under worst possible DBA.

conditions. This-change reflects'present.as-built system designiwhile still ensuring:that worst case DBA specification

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requirements are met' ~Since thisichange'doesLnot ' adversely-

- affect. previous accident analyses requirements, there is no increase-in the probability or consequences;of an accident:

previously evaluated.'

The proposed change,does not c,reate.the possibility,of a new or different. kind of accident 4from any accident previously,.

-evaluated because: calculations indicate that a minimium of.

approximately'21.5 KW is' adequate to ensure 70%. relative

~ humidity air leaving-the heaters. This change' doe's not affect-1 the performance or design intent of'the'SBGT system. heaters.

i Therefore, this change does notiadversely affect the accident analysis and does~not create the' possibility of-a new or different kindiof accidentefrom~any accident.previously evaluated.

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~Attschm:nt l'to AECM-86/0052' h:,

The proposed change does not involve.a significant reduction in the. margin of safety because calculations demonstrate that a.

minimum of.approximately 21.5 KW heat dississipation.ic all that is required to ensure-70% relative humidity air = leaving the heaters. The calculation conservatively assumes a SBGT flowrate of 4500 cm when only 4000 CFM is required 'by FSAR.

analysis'_ assumptions. Therefore,.the proposed minimum of 48 1.5 KW is a conservative number with respect.to requirements'and the margin'of safety is not reduced.

Therefore, the proposed change involves no significant hazards considerations.

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