05000339/LER-1980-028-99, /99T-0:on 800624,during Beginning of Core Life, Hot Zero Moderator Temp Coefficient Found More Positive than Required.Caused by Positive Moderator Temp Coefficient Discovered During Startup Physics Testing

/99T-0:on 800624,during Beginning of Core Life, Hot Zero Moderator Temp Coefficient Found More Positive than Required.Caused by Positive Moderator Temp Coefficient Discovered During Startup Physics Testing

ML19318C382
Person / Time
Site:	North Anna
Issue date:	06/26/1980
From:	VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19318C366	List: 05000339/LER-1980-028, Forwards LER 80-028/99T-0 05000339/LER-1980-028-99, /99T-0:on 800624,during Beginning of Core Life, Hot Zero Moderator Temp Coefficient Found More Positive than Required.Caused by Positive Moderator Temp Coefficient Discovered During Startup Physics Testing
References
LER-80-028-99T, LER-80-28-99T, NUDOCS 8007010415
Download: ML19318C382 (3)

LER-1980-028, /99T-0:on 800624,during Beginning of Core Life, Hot Zero Moderator Temp Coefficient Found More Positive than Required.Caused by Positive Moderator Temp Coefficient Discovered During Startup Physics Testing

Event date:
Report date:
3391980028R99 - NRC Website

text

{{#Wiki_filter:- - - - /It LtCENSEE 3 VENT REP 0a r !Q ' t .sw.x L ; f f t

? u

. a m.. ~ r i?; a v._ m. a :.. ;c a., ;. ;,.

s 'iB iT -~ A : NIA!S12 !?! 0 !0 !- 10 l O l O i 010 l I0 i O !C 4 ! 1 I l I l i l,'fi';:P' rn. FTi @ V' i i a M, Ese cc ;s d

s uce.% :u.s

~ - m3 e

..x - >t:I

.'f '.[.( l L !@l 0 ! 51010 10 13 i 319 j@! 016 i 21 41 8 l O '@l o 16 12 16 i s lo l@

'e:E:.r o2ac.$tanou ANu unosa?u?cNNsYNir:cas h oi2i ! Measurement of all rods out, beginning of core life, hot zero power moderator temperaturel a 1:1 l coefficient revealed it was more positive than 0 AK/K/ F as stated in T.S. 3.1.1.4.a. i

- 3 a ia j ; A value of + 1.39 pcm/ F (1.39 x 10 % AK/K/ F) was obtained after Doppler correction.

l ,.,. 3 ; ; The heal.th and safety of the general public were not affected. j aiis!I I O'7!l l oniI I 3 3 0*' SYSTE*1 C A'.;5 5

CAUSE

C G'.*?. VA. v g COOE CCOE SU3 COO 3 OGY30'!!',7 C005 s*,;3 *.0 0 3 sg3;oog oia! I Rl Cl@ l Bj@ l A l@ l Zi Zi Z !Z (Z lZ IQ l Zl@ lZ l@ 2 o n 12 i: u o 550U5.NTI AL OCCU: AENCE R3 70r.T H E NO'8 t ; > 'PO EVi?JT Y3,h 4 R i7 ORT NO. CC92 Tv?i 1:0. @;Njg 18101 1-1 101218I I/l I 919 l lTl l-l 10 l t_ 2 8 22 ?J 2: 25 27 23 2.2 33 3, 32 ACTi,% FUTURE E :ECT 3MU TO O'.*01 AO C'r..: E N T N 2id O-a Pi::V E GG?.17 CC???TriN T T A < fi4 ACTIO.N ONPLANT METHOO HOUas 22 sy3yt TED FO=u dus. SU >?tti t ?.?A':05 ACTU R E R l XI@! X l@ l Zl@ lZi@ [ Ol 0l Ol l lY j@ IN l@ l Z i@ l Z 19 l9 19 l(' u as 3s u 31 m ai <2 a v carn = cascaianon ANo cosascnVE ACDONs h i ta6 i Startup physics testing revealed the presence of a positive moderator temperature coef-ti siil ficient for the hot zero power, all rods out configuration. Rod withdrawal limits were._ ,,,,; instituted to restore a negative MTC. [ !atI i ... I I i , i a OTwf a status g* n c...T, usia00 03 rr:scavEay oncmmon gQ SidTb5 % PO*hEA 0;tCovE9Y ' B j@ l 0 l 010 l@l NA l l B l@l Startup Physics Testing l i I r, j t_ g 0 i9 i2 il 44 43 es 30 ActiviT / CO?4TE?17 O. a!!sas50 ":egitgA33 A?gc l..T C A 4;Tf't;TY 2_3 L7'ATIO! RELI453 i l4 l l Z l @ l Z lgl NA l l NA l e.. ic n 4., c. PIHJG%%51. E APC50G ES

st.*-3 5. t TY/c D E GOR'2TIO?i 2.

! 7 I l_._01 01 0]@i Z l@l NA I i a. ii i2 u Pih$0%'d.,INjubils l'4ll I I 0l@l A I l 1 'J ti 12 E LO s.'sa in O AuMS TC rateLI rY C. Tis ci Cne2rio% s,e i ! al ! Zi@l NA a., i., o P..., i rY ,u.,, :.norn, Q, .we :n onty 2ioi Litjsl N8 0 0 7 010 F/f I i I :I I I I ' i i i ! '.)

9 !* . b. Virginia-Electric and Power' Company Attachment ~1 North Anna Power Station Unit 2 Page.1 of 2 ! Docket No. 50-339 Report No. 80-028/99T-0 POSITIVE MODERATOR TEMPERATURE COEFFICIENT on-6/24/80, analysis of startup physics testing data revealed that' a positive moderator temperature coefficient (MTC) was present for the all rods out, beginning of core life, hot zero thermal power condition. The finalized data indicated an isothermal temperature coefficient of:

- 0.630 pcm/*F, which converts to an MTC of +1.39 pcm/*F when corrected for the Doppler contribution (-2.020 pcm/*F), was present with an RCS boron concentration of 1332 ppm. -The rod withdrawal limits illustrated by.the attached figure have been instituted.

It is estimated that~a core burnup of 3000 MWD /MTU will be required to restore the MTC to within its limits. The withdrawal limits will apply throughout the entire first cycle of the unit or until a negative MTC for the ARO configuration is verified by measurement. D 9 J l l 1

gggetT C0Hi?US l N3 P00R QU W U NORTH ANNA UNIT 2 - CYCIE 1 i MCDERATOR COEFFICIENT PDD WITHDRAWAL PESTRICTIONS 1600 L 100% -._5._ _ j ~~~ 5 CCNTPOL EOD INSERTION LIMITS j --- o% 2:2 F_-; ___.-j ...+ g _._ge 75% ._t - = ~~ q==-- s x4 c----*- .l 1400 __. _._i__ _.,_ ; m --+ 50% .L._ a+ -r r I t + t = 25% J' = + E .__ _ L.. 7 N P t--

• ~

0% m 1200 _ _ _.. -- %._ _.t:. =n_t ;r.. 2...~-_.. __ _ g _...qn., _. =. .x_.d. x__=.=. _..n. r 4__c -- n n.,.. _ __-. ~ ~:: ..._.3 3 .( -=- t ~ n. m h =g_..,=...._x._.-u_. r-- -- - - d-r--r L =_. m

_..._-------l

": t:n -~

,__a._----

p i .....i. _ _ _.*t NOTE: OPERX'"'CN NOT PERMITTED E..._. _...____.i ,.... _. _..-......_a . =.. ; = -. c r =.._ :. _.=.. n..- a. : _:~. ; ABOVE THESE LINES h,..;_=.,.,_.___"m _.T,. 3 __.C_.., +- i. g., =. m.:... ={. =1;_ ;n :. =*:. _ m r: :. n_. _..:; _.... _ g :r --...d..t.a ....=_." - =_."-,. =... :.. _ _-._. ;y ..q.. ......- _._.2 a.._... .....o m...... z i 1000 t =- = n t - -- m.. _. __2 - : : m. _ -- ' : ; m.. _=- %... t, _.. .t.. t =n. =;=_ =._;. y.- s ' = _;...... = --{! -- - 22:;.:2 I '..'::C .'"_._ a' LC : -.J~~*., c I

- urxx ur-- =:=tr_:. =. - - - - - - -

= :. c- =: -cr---l 8 m.;:- x== = = r---. t___ === __ :=== r=nr t.-- In= = t 2:= ~. : -t:2.:

I.__ --i

}. ---_.;. =_._.. = =___; =__...._ t.__.... _ _ _ _ _ _ _ _ _ _ -.1-- ! _~.~ *- ~ C_ C_ _ =_ _C__"_._* t. Z_ _Z..- -. -- __:.'.~.--

-------' _= 2rp=r: :==

n' .__m. =r..._..;... . ; _.;;~ # ~ C. _*_ _.- __- " f -W - !: =_.t--- =_. _.. _ _ _. ___}_-_C.._C'..-.2.____._..- T..O_.*-.. t. i nl.=_ _ _.___ _ - -. :. (.. n.._.n:.:r. u. n..nt=t r_t. =_.t __,._.-..r____ _.:==._=_. =. _ _ r. 1 :=. _.,.=.. t _.._.r.__. ..r ..f"..__._. J..... .~ ;.g. ....._.._.. __ _ ___ [= $ - : r*- t :"' : t :--~-4: '-.~._;.. l ::.m r .=............j. ... i. ;...... I _.;f.,; : ~' t n= -- --r-.:=d ..+__u_.. : t=! _r = r-- q_=.. - ;.. - =. _===: :.: = :. t- - "n:-L: : = " _=--_; ._'~'. ~! :h d. ~ _. 9 ; =.I2t-6---99h*I [-i-~:.M.. :- N!95?Cf.hb2 EC.}C.2 U_CN'N ..._.: = :.. . = -. . = : :_....: i: =---- *z - :. =... i 1 I I i l I t l l t 100 140 180 223 l' _m... i O 40 80 120 160 200 228 i l l l OVERLAP BANK POSITION (STEPS) i i }}