ML20150C737

/03L-0 on 781006:Westinghouse Reported 0.5% Error in Apdms Limit Calculations Due to Roundoff & Addl Apparent Error Totaled 1.5%,creating Potential for Exceeding Apdms Limits.Caused by X.Xxx Format of Apdms Calculations

ML20150C737
Person / Time
Site:	Zion File:ZionSolutions icon.png
Issue date:	11/03/1978
From:	Perdikis G COMMONWEALTH EDISON CO.
To:
Shared Package
ML20150C735	List: ML20150C732 ML20150C737
References
LER-78-102-03L, LER-78-102-3L, NUDOCS 7811240208
Download: ML20150C737 (1)

Text

w wo U. S. NUCLE AH REGUL A f 0HY COMlhl% ION (7 77) I LICENSEE EVENT REPORT l CONmOL HLOCK- { l l l l jh (PLEASE PRINT OR TYPE ALL HEQUtnED INI OHMATION)

Io l i_ l [ Il LI ZLI_1 s I lj@l o I o I -l o I oJ_o I o I o I -I ol o l@L4 l11 111 l ll@l I J @

7 8 'J L K,f NSL t COD [ 14 lb l lC L f r..L NuY M H b 't, LtCt Pv5l l YPE JV bl L A1 tib CON'T l o TT'l ."ZM LX_J@l o i 51 o I o [ 01 31 o I 4 l@l 1, o I o I 6171 aj@l li l l ol 3 l 7 l a lg

/- e cu oi pOCa r Nurat h i.a u t v r N1.c A r t _ _la 75 ntPOnT crit n EvtNT otsCHIPTION AND PROUABLE CONSE.GUENCES h LoJi] twontinghnunn renorted a 2,5% erraar in the 12DMs limit calnnlations due toj Fo l a l Lroundof f. Investigation at Zion revealed an apparent additional error f lp

[Tf7'l [f rom the roundof f of actual Pz and the input data of the Kz profile for al LO 15 I [ total error of 1.5%. Westinghouse was informed of the findings.Thus a po j FTiG Ltential for exceeding the APDMS limits was created. APDMS limits contain l l l

lol7lla 12% conservatism.Thus it is unlikely that the FQ limit of 2.04 was ex- l l 1 o le ] [cee.ded.Results of full core flux maps substantiate this conclusion . l 7 8 9 b0 SYS1 E M CAUSE C A US E COMP. VALVE CODE CODL SUSCODi COWONE NT CODL SUBCODE SUBCODE '

10191 7 8 1 Tin l@ la l@ l Al@ l 1I Ni s l Tin I ul@ l Yl@ [Zj @

9 10 12 l

11 13 n 10 2u SEQUEN TI AL OCCURHENCE REFORT "lVISION HTO L RE F OHT r.O. COOL TYPE NO.

O g((.g l 7VENT l 8j YEl-l AR l1l0l2J l/l l0l 3l l Ll l-l l3p 0l 21 22 23 24 20 2; 2n 2 Su 31 ACllON F U TUHF (ffLCT SH UT D O'.'.'N ATT ACHY E NT

• PRD 4 FRP/E COMP. COMPONENT

'IAKEN ACTION ON PLANT M E T H OD HOURS SUUMIT i LO F Gk .i dub. SUPPtifH M ANisF Ae^ r t pr H lJ3Et@LxJ@ J4 IZIO 3a I Zl@

Jb jolol0l

./ 40 l

lNl@

46 l N lg 4) l Nlg l Wll] 2 l0 lg 43 44 47 cAuse oEscmPTION AND CORRECTIVE ACTIONS is duch l i l o l [The cause of this non-conservatismato the fact that APDMS performs j 11 l i l [ calculations with a x. xx format. The re fore there can be a 0.5% non- i

[,;7j l conservatism introduced whenever a roundof f to 2 decimal places is l l l

[r[ T] [pe rforme d. APDMS limi ts we re re duce d by 1. 5% to compensate for these l g ] errors. Future action may be taken pending Westinghouse re commendations .;

I U !) g F ACitlTY -, ULTHOD Of i PUWl H b l A'I t G O l ' ' L H S T /. T U'; Du;;Ovt HY DGCOWHY DESCRIPilON 37 l I1 l 5" I l H l(h I 0l 0 l0'2l@l" NA l l D lgl Notification by Vendor l l ASuvnv C$ r t N i 44 * " 80 nc u Asto or no r W A90UN106 L OCATION OF HE t E ASE @  !

l1 l6llZl@ lZl@l

/ H 9 IJ 11 NA ACTtVnY @l l 44 49 gg l l i t MONr.! l [ Krtut:HLS n NUMuth T N Pt ltI7Jl0l0l0,J@lZl@[DI SCHiPTICN' QNAh l

l

/ ti 9 11 17 13 ,

W.

PiHSU % [t nJUnil5 sQ^

NttVUt H D[LChtPrlON 'd ed" li ls l LoJo 1018l

/ 11 9 11 1/

NA l p ,)

L0 % of DH I; AU At.f T O F ACII I T y 1 i PI Iet ht:HWi )N >

Pl LZJOL M 5.1 'U NA l OUUl H't f y l'AUt i

!Y 8 LN_lh,)l13L5t,IIH'ilON NA l [,Jll gjjll lg 8 9 "i u no ..;

NAW OF EHEpt,H[ p Ge or ae ,C . Pe rdikis _ pngyt_312-746-2084 X-245 {