ML17164A940

Forwards Draft Document,Which Was Transmitted by Facsimile from Pp&L,Inc,Providing NRC Staff Advance Info on NRC Regulated Activities

ML17164A940
Person / Time
Site:	Susquehanna
Issue date:	12/31/1998
From:	Nerses V NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
TAC-MA0342, TAC-MA0343, TAC-MA342, TAC-MA343, NUDOCS 9901110319
Download: ML17164A940 (16)

Text

December 31, 1998 MEMORANDUMTO: Docket File FROM:

SUBJECT:

Victor Nerses, Senior Project Manager Project Directorate I-2 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation SUSQUEHANNA STEAM ELECTRIC STATION, UNITS 1 AND 2, DOCUMENTATIONOF ADVANCEINFORMATIONON NRC REGULATEDACTIVITIES(TAC NOS. MA0342 AND MA0343)

The attached draft document, which was transmitted by fascimile from PP&L, Inc.,

provides the NRC staff advance information on NRC regulated activities.

Docket Nos. 50-387 and 50-388

Attachment:

As stated DISTRIBUTION Docket File PUBLIC PDI-2 Reading VNerses OFFICE PD 2/P NAME V erses:r DATE

/~/E /98 OFFICIAL RECORD COPY DOCUMENT NAME: SU0342.MEM 990iii03i9 98i23f PDR ADOCK 05000387 P

PDR

pe REGS

~o Cy I

I Cl0 IVl di O

+~

~O

++*++

MEMORANDUM FROM:

SUBJECT:

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 December 31, 1998 TO: Docket File

'rNe, Senior Project Manager Project Directorate I-2 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation SUSQUEHANNA STEAM ELECTRIC STATION, UNITS 1 AND 2, DOCUMENTATIONOF ADVANCEINFORMATIONON NRC REGULATED ACTIVITIES(TAC NOS. MA0342 AND MA0343)

The attached draft document, which was transmitted by fascimile from PP&L, Inc.,

provides the NRC staff advance information on NRC regulated activities.

Docket Nos. 50-387 and 50-388

Attachment:

As stated

2

~

Robert O. Byrarn senior Vice Pieafdant Generation and Chief Nuclear ONcer Tel. 610.774.7502 Fax 610.774.5019 E~it: rgbyramepapt.corn PPLL, Inc.

'Jwo North NinlliStreet Allentown, PA 16101-1179 Tet, 610.774,5151 httpifwww.ppl.inc.colnf V.S. Nuclear Regulatoty Commission Attn: Document Control Desk Mail Station P 1-137 Washington, DC 20555 SVSQUEHANNASTEAMELECTMC STATION SUPPLEMENTAL INFORMATIONREGARDING CHANGE OF TECHNICALSPECIFICATION FOR ULTIMATEHEAT SINK AVERAGETEMPERATURE (TA@NQS"'.-"5@0342 A89:;MPA'0A'3'~

"""-"-"',='<""~":-"":. i,,"-kfQlteo 'Nbf;

~nese i.~m Zk'l

1) Pl& 4P+d

-"PscP'o'ced Aincndsncnc Noc22TSVo@ensc NPX 24An)r P'coposed Ass)ersdnsens No. 182 To I&jnscNPW32r UltifrjgeHeat,gbrk AveragV~'femperygyrep Pd dnted Junc I, ILr8.

For Addi'tionalXnfoimation Itegardr'ng Change OfTechnr'ca Speci%cntion For Ultimate Ilent Sink Average Temperature, dated October 90, 1998 3)

Pf>-dt99I "Response To Request For Additional Information Regarding Chnnge Of Teclinicnl SpeclJlcatlon For Ultinrate Heat Sink Average Tenrperature," dated October 90, 1998, d)

I.etter dated September 8, 1998 Jrom V. Nerses, Senior Project Manager, NRC to R. G. Byrarnp Senior Vice Prcsr'dentnGeneration, PPZcT., "Request for Additional Information (RAl) Regnrrling Change Of Technical SpeciJication For Ultinrate Heat Sink Avcrngc Temperature for the Susquehanna Steam Electric Station, Units1 and Z."

The purpose ofthis letter is to provide supplemental information supporting our proposed chattgc to the Technical Specification (TS) surveillance requirements for spray pond average water temperature for Susquehanna Steam Electric Station (SSES)

Units 1

and 2, submitted via Reference (1). The follow-up information was identified during a teleconference, Rcfcrcncc (2),

to discuss our response, Reference (3), to your request for additional information, Rcfcrcncc (4).

The supplemental information is contained in Attachment l.

Ifyou require any clarification regarding the attached information, please contact Mr. J. M. Kenny at (610) 775-7535.

Sincerely, R. G. Byram ATZACHMENT

1 ~

~

PLA-XXXX Document Control Desk Attachment copy:

NRC Region I

=Mr. S. L. Hansell, NRC Acting Sr. Resident Inspector, SSES.

'r. V. Nerses, NRC Sr. Project Manager Mr. K. Kerns, Pennsylvania DEP/BRP pg p~

+gl1Htt&~4%

4A'g~

lil II

'NI

'iI vt IIIl4 IllC IIII

~'

SUPPLEMENTAL INFORMATIONREGARDING CHANGF OF "

TKCHNICALSPECIFICATION ZOR ULTIMATEHEAT SINK AVERAGETEMPERATURE

ATTACHMFNT1 TO PLA XXXX Page 1 oM'3 SUPPLEMENTALINFORMATIONREGARDING CHANGE OF TECHNICALSPECIFICATION FOR ULTIMATEHEATSINK AVERAGETEMPERATURE

Background

A telephone conference (telecon) was held on December 1, 1998 between members ofthe NRC staff and the PP8'cL, Inc. (Pp&L) staff to discuss PP&L's response to an NRC request for additional information regarding PP&L's proposed change to the Technical Specification (TS) surveillance requirements for spray pond average water temperature for Susquehanna Stc'am Electric Station (SSES) Units 1 and 2.

Anumber ofquestions were apparently resolved during the telecon, as follows.

1) There was general agreement that PP&L's shiAly surveillance procedure, whereby average spray pond temperature w'as determined 4 times more frequently than required by the TS, was a good practice and provided some assurance that an increase in temperature might bc detected sooner than otherwise.

rd')It>as exp'fgned thatsahort-terr+It.-',worst cdogs'=diesel-t,erirl'ator (DIG)jaittngs'(4'IltO..kw for D5 A-D ancS500 k~tfor DGAp were @surged in the ~pray p'Ond minimum heat 't'ransfer=

(MHT) analyst". which'cr'eppes'%ighergeat 7@d inputWy.'.calculation tffan thc steady sage ratings ($000 kvFpr Doh-D andgfOYkmgor DG Rp. Act'ulal post-LORNA DG loading fbilallDGs~agept at jg beiovTge DGX'-Dsteadj"state r'pg.

is~ al~lcN~tr RgisSSS a<<>PN

~Std~

I'IIIIllllllllI

3) It was explained that the spray pond average temperature measurement error allowance of 0.5 F was incorporated in the MHT analysis by increasing the initial condition temperature for the calculation from 85 'F to 85.5 'F.

4) It was clarified that, upon receipt of the spray pond temperature alarm, the operators take action to cool the pond by running the sprays. In addition, operating procedures instruct the operators to cool the pond when or before the pond temperature reaches the TS survcillancc limit. It also was clarified that the nominal 2 'F margin between the spray pond alarm temperature (83 'F) and the TS average temperature limit (85 'F) should provide suiTicicnt time for operator response.

This is because the alarm can be actuated by any or all of seven resistance temperature detectors (RTDs), five ofwhich are near the surface, whereas thc TS limit is based on the average reading of three RTDs, two ofwhich are deeper in thc pond, Because the surface temperature is expected to be greater than the value of the avcragc temperature reading, the alarm should occur well before the TS average temperature limit is reached.

5) It was explained that process measurement uncertainty was resolved by performing a

calculation to compare average spray pond temperature based on the 3-clement RTD array'o average bulk temperature based on enthalpy, and that the results were within 0.1 'F.

During the course of the telecon, the NRC staff identified the need for some supplemental information. Specifically, the NRC sta6'ndicated that PP&L's estimates of rnaroin due to

ATTACHMENT1 TO PLA XXXX Page 2 of&3 conservatism in analyses of ultimate heat sink (UHS) performance, including the determination of maximum average initial spray pond temperature, needed to be formalized to support the requested change to the Technical Specifications.

Tem erature Limits and I strument Uncertai t PP&L has performed a preliminary calculation based on revised input and modeling assumptions to determine a more realisticbut still conservative analytical limit for initial average spray pond temperature.. Two of the revised assumption's still contain conservatism,,while the other two are considered realistic. The revised'ssumptions are:

1. A more realistic but still conservative average spray pond level is assumed in the MilT analysis, resulting in greater heat transfer by increasing the eFective distance (relative to the previous analysis) that spray'roplets travel through air from the nozzles back to the pond surface.

2.

Ambient heat loss into the. concrete basin has been calculated in the MHT analysis with a conservative assumption regarding thickness of concrete this accounts for some heat rejected from the spray pond to the environment.

3.

Heat trans fe'rpom the Elleanti'+p SW tlupi@Esw anTgiilN+'jmjj1jitjstanl'tsjjnjjolien ts has heels caiculateti'itis the sNff snag]st this tedrgicaljy accujmts fos amhjent heat lo'ss fcom thc EQV and RHRSP sys'tern%~~

4.

Ptlik)p energy jf@osite~to th~orking,giiid in tIi'e:,'MHT iA'ilysisfs assumed t0;bc 95%, which ivplqt'g.<qliQi than.tWip0% pY@jqtlq.~~umed..L.

Based on the preliminary calculations using these revised assumptions, the analytical limit for initial average spray pond temperature for 2-unit operation's 87.5 V. The corresponding requested Technical Specification surveillance limitof 85 'P will provide adequate margin to this analytical limit. Similar calculations, for 1-unit operation with one unit shutdown at least l2 hours and for 1-unit operation with one unit shutdown for at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, show revised analytical limits of 89.5'F and 90.5.'F, respectively.

The requested Technical Specificatioii siirveillance limits of 87 'F and 88 'F, respectively, will provide adequate margin to these analytical limits.

PP&L expects to finalize the calculations by approximately mid-January.

PP&L also has performed a new calculation confirming spray'pond temperature uncertainty. -A -'-

previous calculation had determined temperature loop accuracy to be +2'F, which is consistent with design accuracy.'he new calculation, which takes into consideration accuracy of all loop components, repeatability, readability of indicators, calibration accuracy, and driA, as well as biased accuracy for non-independent (shared or common) components, shows an overall uncertainty of+1.97 'F.

'hc rcviscd assumptions conelatc to consctvative assumptions 10, 12, 13 and 17, rcspcciivcly, in Lciicr Rcfctcncc (3).

~ Two units operating (or one unit operating with one unit in Mode 3 less than 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />).

Loop accuracy calculation performed in 1988 and rc-approved in 1994.

'+2% of 100'P pcr SSES FSAR Table 7.54

r

ATTACHMEH7l TO Pl.A XXXX Page 3 of3 As indicated above, preliminary calculations demonstrate that there is adequate margin bctw'een Spray Pond analytical limits and the corresponding proposed Technical Specification surveillance limits, subject to =confirmation in finalized calculations, and that spray pond temperature uncertainty is bounded by these margins.

p

u A

roach to Calculation ofUncertaint Term for Avcra S irav Pond Tcm craturc

~aea round To comply with the TS surveillance requirement, the operator takes a reading from each ofthrcc tcmpcrature loops (T-0122SE, F and G), which are independent except for a common temperature indicator (TI), and divides the sum of the readings by three to gct the avcragc, which must bc Icss than 85 dcgrccs F. Thc operator uses a handswitch to select which temperature loop hc would like to read. Each loop consists ofan RTD (TE), a temperature transmitter (TT), a signal resistor unit (SRU), an indicating amplilicr (TY), and thc common temperature indicator (II).

g~o~ac l.

Thc GE sctpoint methodology was used to calculate the total loop and calibration uncertainty for onc loop and for the avcragc of three loops.

P%~ y~

2.

Thc methodology us< tne s'qU'Qe zoogo the ofthejquarcs"(@US) to combine thc unceriaint terms, including co@onenL acFuracjf,'alibratijraccura'gy, and ding. Onc<igma numbers are dcrivcd from I ho ma nut'aetuijdte'at'h by d9t'direr the atatert aeetitesr Jrtidtuo. Piant data were used for driit.

3.

Thc SRSS was used N combine the)ndepcndent'.:~raj~

cafi9pation accuracy, and drifttcrins. Thc indcpcndcnt accura~tcrms arc the"yiccuracy te'rms associated ioj1$ indcpcndent components. such as the I'E, TT, SRU, atilt, and the reopc'aIQURy accuxacgfar the%'>A multiplier of 1.645 was used in this calculation to give 95% confidence that thc uncertainty value was calculated with 95%

probabi) ity (95/95).

4.

Tliisvalue was then divided by thc square root of thrcc, based on the Central Linut Theorem of Siatis(ics, to arrives(4y cabined ullgertai~forytpcsycrage oglireescadings (associated with thc indcpcndcnt components).

5.

Thc terms not included in step's 3<ad 4)i,e., thc3jiaseh accuse'~ terms ass@atcd with thc cominon Tl) included the accuracy ternt oftJfc.TI' portl$fYof&ecali@ation accura'cy. assumed to bc attributablc to the Tgassuincii to bc"haP ofthemquircd finafgj-Jclt tolcrapqe value) and a portion oi'lic driftassumed topi'attribiltable toVje Tl (assiimcd to bc hat@/ the historical avcragc as-found loop driitfrom pla5t"Santa)."'Hpcse werc'combined%sing the SRSFttfeoioZ(including thc 1.645 multiplier).

6.

Thc result from step 5 was not divided by the square root ofthree since it is common to all thrcc tcmpcrahirc readings.

~iereo Ng <rn+

wd'Aywo ant rg,.

n'rr tre 7.

Thc results from steps'.pan&".were corn%i'ried using*mt'hc Sos'to arrivo'R) 0>e to'ilfduncertainty, which Accuracy Terms Vayu'c (6);~

e+

33ovrcc DiviilcBy g(3)

Accura ofTE

'b':

.0 584'F P.:"" Roseillount bul e tin

\\e ~

Ycs Rcpcaiability ofTE Accura of Tl'ccura ofSRU Accura ofTY Accurac ofTI Rc catabilit ofTI Rcadabilit ofTI

"'bQ 0&%"max iccPjemt shiit 0 23'F 0 25OF 0.1'F 0.5 F 1.5'F I'

Rosemount'buf) ctin IOM 145 Telccon w/ I&,C Telecon w/ I&,C IOM 119-3

'IOM 119-3 Calc EC-0544578 r ere Ycs Yes Ycs

..No Yes Approach.doc 12/28/98 7:52 AM

4 A ) roach to C Iculation of Uncertainty Tenn for vera e

ra Pond Tern eraturc Calibration Accuracy Terms Final Tolerance ofLoop KeithlyVoltmeter Dccadc Box Value (+)

0.6'F 0.015% reading plus 300 microvolts 0.019 DF) 0.02% setting

+4rnOhrns 0.1D Source ISAAC Ready Data Shccts Telecon w/ IA,C Cal Lab Telecon w/ TEcC Cal lab Divide by g(3)

Half(Halfassumed to o with Tlg Ycs Ycs TE Drift yt Value (+)

~0;08lmmax,i'p'oti"nt':

gesiitangshift

follrtttving 15b0 hours at

"~"-.max s'pacified te eraturh

,.(0.37'ource 8

i~.

"; Ro$crnount by!1etin

( ~ '

Divide by+3~

Ycs Rcmaindcr of loop 1 03d",~> Plant jfttta at M:(Fyoint od"'all"fEloo 's'.-Q)

Half(halfassumed to bc associated with thc Tl) t>>

4(

rr ~

~ (b

~WMxi

>> C~(b

>>r(

I

~

'I(>>

I>>

1(~7.

~fr r <<.1

'Cr( il 4i r~>>

I>>>>r (I (lki>>((+(

~c c

~ t(11 h

c' (I

<<rc

'4>>

~ >>(

~ '!

.+I

Fy~

y, t((I

~

~

I~>>\\

f+c '

/"

VI

&ri<<

HEknr(<<>> r

>> rr(Q>>

M Ir I

<<'b>>di b( Qt'.b'c i',

.r('

<<h I(>>(

r "r

<< II IC'P

~

• yli tD I~yc

'pproach.doc 12/28/98 'l:S2 AM

1 j(i N

I