ML17317B539
| ML17317B539 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 08/03/1979 |
| From: | Dolan J INDIANA MICHIGAN POWER CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| AEP-00221A, AEP-221A, NUDOCS 7909180529 | |
| Download: ML17317B539 (14) | |
Text
INDIANAl MICHIGAN POWER COMPANY P. O. BOX 18 80 WLI N G G R E EN STAT ION NEW YORK, N. Y. 10004 August 3, 1979 AEP:NRC;00221A, 4onald C.
Cook Nuclear Plant Unit Nos.
1 and 2
Docket Nos.
50-315 and 50-316 License Nos.
G. Keppler, Regional Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Avenue Glen Ellyn, Illinois 60137
Dear Mr. Keppler:
The attachment to this letter contains the first progress report on the feedwater line data collection program in Unit No.
2 of the Donald C.
Cook Nuclear Power Plant.
The data collection program was described in our AEP:NRC:00221 submittal dated June 15, 1979.
This progress report is submitted in accordance with the com1itment made in our AEP:NRC:00216 submittal dated June 15, 1979.
The AEPSC interprets 10 CFR 170.22 as requiring that no fee accompany this submittal.
JED:em Very truly yours, ohn E. Dolan Vice President CC:
R.
C. Callen G. Charnoff R.
S.
Hunter R.
W. Jurgensen E. Jordan -
NRC T.
E. Campbell - Westinghouse G. J.
Schnabel
- PSEKG q )979
/I4A
!!!I'$00>So~
I'l(()()ItlGli iH'I'UI(T I'ecdwater Lyric Data Collectinr) I')'o~)'a!)
. nt) od>>c t;ior!
A t;est.
I.rogram was
)>>c~;>>ted y in',3:ii.cd o>>
t.~:.~i for!<I.;.-<l.~."..
lines ~f D C.
Coos Ur) t, 2.
Thc pu) I)o e of t,hi program was t,o collec da' on steady state and t;)'ansie>>t cor)~ai t.ions I
nurir>t, r)o mal nlar)t oiieraI.ior> from two.".tear", gc>>c).".',( 1':
a>>:I I
.heir."ssoci"'ed fce<Iwatcr I i ping.
I)ata o>> pipe mo'.in>>s,
",train-, pressu's and t,empcra'.urcs were coll~ctec! from colo shutcown to full power and t) i.p from full lo:!d.
<Ie;;r!!l
'Iestinghouse are collcctive3i in t;hc proc(:.".." of ).educ.! r);
evalua'ir g the data collect.cd.
- reliminary rcvi,cw of the data
')as revealed a cyclic a:::;
steady state tcmperat;ure phenomenon which was unforseen pr.'n) to dat.a gathcrin".
Sample of thi" phenomenon will be pre-sented in this report.
- Heroin, we will describe th ins;ru-mcntation set-up, test procedure and out;line our fut,ure plan" for data reduction and evaluation.
0 Test Instrumentation Test instrumentation was in"tallcd on the <<uxiliary ar)d main feedwater piping a>>d stcam ger!erator ferdwate)'o'les fu) loop'nu!nber one and t;hrcc of U>>it 2.
Thc c loops werc 1.>>strumc>>lcd
~ ~
ident,ically wi t,h rospcct t.o t no, 'quaii'i ty <<riit lo<<:.tiori of to" t; instrument,.i.ion.
'i'}ic loops woi o inst,r>>:::~.>>t,od I>> t.'hi:
- m;inner t;o insure rediri>da>>cy of:informatio>>.
Tho following is a brief summary of.he number and locat'on of t,ho-vari-ous ty;:osof t;ost in: trumont'a'.,ioni Strai n G;i o
~'welve (12) traili g'a j'e cha>>>>ol.
"0 loc>>
wes e utilized t;o obtain d,.ta or.:
hei ldillg ~ torsl 011<ti <<rl..
ial stresses on the si xtoen irich elbow;it; a locat" cn a(.J':-
cent tc t}io elbow lo>>o':zlo wold and bcii..'irig "t: os: o" o>>
t:ho team generator no "zoo. T}:roc (3) str,.in ga,os
. cro u.",cd tii measure loadings on t}iree seismic snubbors.
Accol oromote~.;:
Thirteen (13) accelci omo.or pr r Ioo"..
we. o utilized to moriitor p'os"ible o ci21ations of tho stoa:~
Generator a>>d t'c a sociatod main feed::ator p-pi>>g i: t}ii>>
the contai>>mont.
Acceloromotors were placed at each of tho three feedwater line elbows inside the containmont cuba>>e wall, midway along the vcrtic;il riser and on o>>o of the seismic snubber bases.
T}io>rococo>>nles:
Twerity-three (23) thcrmocouplo
. per loop wore used to me;isure:
circumferontial tom}!erature distrib;i-tion on the noz..le, associat;od weld and pipe elbow, <<':ial temper;iture "dist;ribut;iori aloiig t}io elbow <<iii} vo> t,ic;il r'sor
=and t,he auxiliary fcedwator t,omperaturo.
In addition, t;wo (2) thermocouplos per loop were placed inside the elbow, approxi-mately six inches upstream from the elbow to nozzle wold, at the nine o'lock po"it;ion looking into Lhe st;earn generator.
Pago
?
These t.hermocouJ>l>>:;
w<! <<>>s<<.
1 t<> mca.,>>rr.
t.hc i>>. J<Jc m< 1.:i1 water temJ>eraturc-.
Pre" sure Transducer:
Five
(~j) J>rcssurc an<I four ('~)
dif'f'erential pressur c traris<Iuccrs werc omJ>lo>>c<J to rno>>'.or os.,ible
!at.cr pressu] c or fin;! oscill, tion:; i!ithin th<<el'>o.
and the main fc"Cwater arrd auxil>ary fee<".:!at, or J)iJ>lrlg.
Disnlac<..>o>>t Trans<incor:
Ten (10) Direct;. Current Dif-fcrential Transformers (DCD'2) pcr loop w<.re usc<t t;o stoa "ur e main fee<lwat;er piJ>c displaccmont within thc co>>'inme>it.
In addition t;o the d rta
> ccor<led on thc abov cha>>ne" ",
control room reading of team generat;or
- pressure, ho'n<i cold leg ter.pcrature, main feed;:at;er temncraturc arid flo;., f<.e'>u.rp
- speed, auxil'arv fee<'.water flow and steam generator leve'o~
l'o.h. >.J>s one and three were recorded.
Test Pr ocedur c The test program took place in two parts.
The first te t;
period began on Junc 28 when the react. or was at; cold shutdo:!n and continued until July 4 when the unit attained full load.
During this phase of'he test program aawa was collect. cd during the following sequence of event;":
a) St;art-up of reactor coolar>t pumps.
b) Various intervals during JtCS heatuJ>.
c) Periods of time that coincided with intermittent; injec-tion of auxiliary feedwater flow int.o the steam genera-tor while the unit was at hot-st;andby.
I aHc d) During u>>i t,: tat t->>p, inc1ud.i>>>;:;t. >p of bnth 'hi main feedpumps and main turbine.
e) At roughly every ten p<.scent power lovel up t<> and including full load.
f) During a turbine stop valve tost sc<tu<.ncc.
Durin" thi s phase of thc test progra.":., data was als<: col-lected,durinc an unplannc<l t>ip from lo;o thermal power.
The final phase of the test program took place on J>>1.;.'3
<<nd con-sistcd o
data collection during a planned. trip fin"..) full load.
Data was rccorde<l beginninC wi th th<. trip <<nd con'inue<',
uiiti1 tge unit 'was s eturned.on 1'c.
Preliniir:nr.
<<exult:.",
Preliminary analysi" of the data reveals that when the unit i at hot-standby and dur" ng startup, the elbows a<',yacc>>t to the team generator nozzle.
and the nozzles exhibited larce circumferential temperature gradients which indicates tempera-ture tratification in the water.
This condition occurs during low auxiliary feedwater flow rates, and manifests as the lower portion of the nozzle and adjacent elbow being significantly cooler than the upper portion.
4'hen the water flow rate i" in-
- creased, in or<lcr to maintain steam generator level, thc uppe~
portion of both the nozzle and,elbow; cool.
This results in a cyclic circumferential temperature gradient when the water flow rate is later reduced and the temperatures return to their pre-vious state of stratification.
Pa g(.'
Thi is shown graphically for two (1iffercnt run" in Figure'l-4.
The variation 'in auxiliary fccdw::),cr flow rate i" indi cat.c(1 on the figures.
The thermocouple locations are s)>own on I'igurc Both runs were proceeded by steady low auxiliary feedwater flow throuch the fcedwat.cr line:;> though this flow diffcrc(! for goth runs.
Thi" account for the diffcrcnt initial stratifica-tion. 'Since th:.s data is still prelimin~ry a fcw channels whose calibrations are uncertain during either ran were omitted for the tire in auestion.
As can be seen at minimum flow the elbow an(1 nozzle sce thc most severe stratification.
hs the flow rate i'ncrease('.
the temperature" at the top of the nozzle and ell.ow decay.
The high-er the flow rate the more rapid the decay in tratification.
As flow is reduce(1 thereafter, thc temperature'mmedi(tcly return to a stratified condition.
The observed cyclic circumferential temperature gradient was accompaniea by cyclic reading" from the strain gage The strain gage readings followed the cyclic circumferential tempera-ture gradients.
The nonuniformity in circumferential temperature during low auxiliary water flow is apparently due to thermal stratifi.cation within the horizontal portion of the elbow ana nozzle.
Data taken during two ascension.",
from zero to,?OjJ
))ower.)low(!(l."LI'li-lar temperature fluctuations due to thc frequent variations
-'n I
auxiliary feedwater flow rate.'..
Once the feedwater 3.inc" wore on main feedwater, variation in tcmpcrature->ierc no longer ob"crvcd.
)'age 5 Jieview of the accelcro::;(:ter
()at."i 6i(! not reve;il "i)>>ific;ir:.
pipe mo ion.
On-line pcctra'>>alysi'(>
selccl,ed cha>>n(:l" during t)ic test ri:ide it pos:;"3e to i(lent,ify t,)ie m.>il:il frc-quencins of pi pc motion bilt t)lc d 3,1)l accirlcilt 8 werc iii::i>>i5 3 cali'..
There
~:as nn evi(jencc of th(: -.ipc being (xci'-(~(l 1>>:;!>>v o::;i(!'~
source.
)'iiial3.y, cxaiiiinatioi. of t)i(. )).i.pin;; QL bo
)1 (io3.(i;i>>l~ )i~).
steaii generator coiiditions (lid iiot s)io;i a>>y '>>tci fc: ence or>>r:-
expect.ed movements.
UOIlG1;1 0
.">>rthcr a>>~3.ys.'
rcq " re.", the translatio!i of t)ic dal,'..
cord((: on magnetic tapes.
1lo..ever, the prelimi.".ary:.(.vic;. of the d;ita, inclu()inc t)ic fiilllo:id triii, su)i.",',a>>tiatcs t)ic con-clusion th;it there is a thcri;:il rcl;ite(l problc.-.i th;:t occurs when the vs tci i i:il. )lot-! t<<'.ii(.);.
ili(l coilt Piles l )irolil,)i ilt ilp >
unti'he svstem is transferred "o main fecdwatcr.
Th=s ge>>(irall' occurs somewhere between 4g;~nd 20;. thermal po":ei.
$iestinghouse is presently in the proces. oJ~" ".izing and reduc"ng the data recorded on magnetic tape Xn'ddition, b(.-
cause our strain measurements give us only the change of stra'n, O
rather than the absolute straiii value> lIesting)>ouse
"." (levc3opiiig a three-dimensional stre" analysis model.
Using our men:>urcd
.temperatures as an input the thrcc-dimensio>>. l moacl ;iillyield absolute stress.
This 'will enable us to develop the absolute stresses caused by the differential temperature pattern ana cor-
,-relate the strain changes as indicated by the strain gages.
Page 7
Our schedule presently calls for completion of the data reduction by early to mid September.
At that time we expect to have initial results from the three-dimensional stress model which will yield the absolute magnitude of the induced stresses and their fluctuation.
The final results of the thermal stress analysis is scheduled for mid October with the completion of the evaluation report due by the end of October.
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