ML18219D857
| ML18219D857 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 12/22/1977 |
| From: | Tillinghast J American Electric Power Service Corp |
| To: | Case E Office of Nuclear Reactor Regulation |
| References | |
| Download: ML18219D857 (8) | |
Text
DISTRIBUTION AFTER ISSUANCE OF OP TING LICENSE NRCFQRM 195 I2 78I U.S. NUC! EAR AEQUI ATORY COMMISS OOC ~QBiW C
NRC DISTRIBUTION FDR PART 50 DOCKET MATERIAL I.E NUMB TO."
Mr>> Edson G ~ Case FROM:
American Elect Power Svc>>
Corp>>
New York, N Y
10004 John Tillinghast DATE OF DOCUMENT 2
2 DATE RECEIVED 12 3
MLETTER
~OR IQINAI ClcoPY ClNOTORIZEO UNCLASSIFIED PROP INPUT FORM NUMBER OF COPIES RECEIVED
'ESCRIPTION Consi sts of evaluhtion regardi a potential limited boron dilution acc't an operatatigg PWR facility due to indadvertent injection of a portion of coolant system.wh1;le the reactor was i cold shutdown condition
~ >>w/att figure 1 of a schematic of the piping arrange from the spray additive tank to its va discharge points, ~ ~ ~ Notorized 12/22/77 ENCI OSURE gdent he the
'he ent ious 2p + 1p BRANCH CHIEF:
7 FOR ACTION/INFORMATION PLAh~ NAME..
DONALD C COOK UNITS 1 & 2 jcm 01/03/78 r&~~M e
INTERNALOISTRIBUTION IJ.
MCGOUG PDR:
-""XTERNALDISTRIBUTION CONTROL NUMBE R m> 't ygua gn>44
~ '
AMERICAN ELEC
~stl@a%P~~R~~
ga) oration 2 Broadway, New York, N. Y.
1000'212) 422.4800 JOHN TILLINGHAST Vice Chairman Engineering and Construction December 22,'977 Donald C.
Cook Nuclear Plant Units Nos.
1 and 2
Docket Nos.
50-315 and 50-316 DPR No.
58 CPPR No.
61 Mr,. Edson G. Case, Acting Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Att: Don K. Davis, Acting Chief Operating Reactors Branch 2.
On September 21,
- 1977, we received Mr. Don K.
Davis'etter dated September 15, which transmitted details of a limited boron dilution accident at an operating PWR facility due to the inadvertent injection of a portion of the coolant system while the reactor was in the cold shutdown condition.
This letter further requested that we perform an analysis to evaluate the potential for and consequences of such a boron dilution accident at the Donald C.
Cook Nuclear Plant.
The above referenced letter indicated that this accident was caused while performing surveillance testing of the NaOH tank isolation valve, with the decay heat removal system lined up for reactor coolant recirculation.
Upon resumption of coolant rec'irculation this NaOH was injected into the reactor coolant system.
In response to the above request we have investigated the potential for such an accident at both units of the Donald C.
Cook Nuclear Plant.
The results of this invest-igation are given below.
Attached Figure 1 is a schematic of the piping arrangement from the spray additive tank to its various discharge points.
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The diagram represents the valving arrangement for the ECCS during recirculation.
The schematic shows that a single valve failure or misposition will not lead to direct injection of NaOH in the Reactor Coolant System.
The spray additive tank contents can only be added to the Reactor Coolant System by the mispositioning of four (4) valves in series,
- namely, tank discharge valve, 2
locked-closed hand valves and the ECCS pump suction valves from the refueling water storage tank.
- Thus, our evaluation has clearly shown that. multiple component failures and/or operation errors would be required to initiate the incident cited by Mr. Davis'etter.
Based on this evaluation, it is concluded that this incident could not occur at Donald C.
Cook Nuclear Plant by the misposition of a single isolation valve or a single active failure of a component.
Hence no corrective action is considered necessary to mitigate the concerns addressed by Mr. Davis'bove referenced letter.
Very truly yours, JT: dp Sworn and Subscribed to before m
this wz"+day. of December 1977 in New York County, New York Notary Public TEILEFN gARR~
y
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f cc G ~ Charn8$ f"'
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R.C. Callen R.W. Steketee R..Walsh R.W. Jurgensen D.V. Shaller Bridgman
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N2 BLANKET~
IO pslg NaOH TNK EL.
58?'.O.
6ll -3 IF1200 2-II2"4 L.C.
PURIFICATION FILTERS IOOgpm 36 I-U2"g sI I 2d 24 III RVIST HEADER 8 gI S.I.
L.C.
L.C, I2"hI RHR CVCS CTS PUMPS IO'III RCS OTHER Sj. PUhIP SZ. PUh)PS RCS RHR PUMPS OTHER RHR FUMP FROM RCS PRrSSURE RANGE 425pslg-IOpsig RCS CVCS PUI.IPS OTHER CVCS PUMP VCT ISpslg k
FIG. 1 POTENTIAI PATHS PROM NOOH TANK TO REACTOR COOLANT SYSTEM
191( DEC 0
iN 9 33