ML19256B541
| ML19256B541 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 07/26/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Short T OMAHA PUBLIC POWER DISTRICT |
| References | |
| NUDOCS 7908060021 | |
| Download: ML19256B541 (1) | |
Text
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'e NUCLE AR REGUL ATORY COT,1?.119S10PJ
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if' AHLING TON,1 C XAS 72;912 July 26, 1979 Nchet I:o.
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- i. ;. ;; :t G:aeral ' r ager 1623 Ilarn: y Street 0:aah a, !!eoraska 68102 Ce n t l.ene n :
The enclosed IE nulleti.n i9-05C and 79-06C la forwarded to you for action.
.ir it t en respoane. are required.
If you den tre addit ional :inforr.at ion r e;.a rd i ng th i.n ma t t e r, please coatact this office.
Sincerely,
- }..m a 4,-l.hb TU. ' '
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a' Khrl V.
Seyfrit s
s,Ili rec to r 1:n c l o n u r e..
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I!: Bu l le t i n I:o r..79-05C & 79-06C
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'f i Bulletinr. 1: ';ued in the 1.a s t I? %nt ha ce 11.
L. Andreus, ::a n ager l'o r t Calhaun Station Pont Oftice Ho:. 98 l'o r t Ca lho n't, tiebraska 68102 790808o o ay
UNITED STATES NUCLEAR REGULATORY C0315!ISSION OFFICE OF INSPECTION AND ENFORCEt!ENT WASilINGTON, D.C.
20555 IE Bulletin Nos.79-05C & 79-06C Date: July 26, 1979 Page 1 of 3 NUCLEAR INCIDENT AT TIIREE MILE ISLAND - SUPPLEMENT Description of Circumstances:
Information has become available to the NRC, subsequent to the issuance of IE Bulletins 79-05,79-05A, 79-05B, 79-06,79-06A, 79-06A (Revison 1) and 79-06B, which requires modification to the " Action To Be Taken By Licensees" port ion of IE Bulletins79-05A, 79-06A and 79-06B, for all pressurized water reactors (PWRs).
Item 4.c of Bulletin 79-05A requtred all holders of operating licenses for Babcock & Wilcox designed PWRs to revise their operating procedures to specify that, in the event of high pressure injection (llPI) initiation with reactor
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coolant pumps (RCPs) operat.ing, at least one RCP per loop would ronai.n operating.
Simi l a r requi rements, applicable to reactors designed by other PWR vendors, were contained in Item 7.c of Dulletin 79-06A (for Westinghouse designed plants) and in Item 6.c of flulletin 79-06B (for Comhustion Engineering desio,ned plants).
Prior to the incident at Three !!ile Island Unit. 2 (Ttli 2), Westinghouse and its licensee:. generally adopted the position chat the operator should promptly trip al1 operating RCh in the loss of coolant accident (LOCA) situation. This Westinghouse postion, has led to a series of nu. Lings between the NP.C staf f and Westinghouse, as well as with other PUR vendors, to discuss this issue.
In addit ion, more detailed anal'jses concerning 1.his natter were requested by the NRC.
Recent preliminary calculations performed by Babcock & Wilcox, Westing-house and Combustion Engineering indicate that, for a certain spectrum of small breaks in the reactor coolant system, continued operation of t he.RCPs can increase the mass lost through the break and prolong or aggravate the uncovering of the reactor core.
The damage to the reactor core at TMI 2 followed tripping of the last operat.ing RCP, when two phase fluid was being pumped through the reactor coolant system.
It is our current understanding that all three of the nuclear steam system suppliers for PWRs now agree that an acceptable action under LOCA symptoms i:, to trip all operating RCPs immediately, before significant voiding in the react or coolant system occurs.
Action To Be Taken By Licensees:
In order to alleviate the concern over LOCA, all holders of operating licensee DUPLICATE DOCUMENT following actions:
Entire document previously entered into system under:
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