ML19256B548
| ML19256B548 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 07/26/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Stewart W FLORIDA POWER CORP. |
| References | |
| NUDOCS 7908060515 | |
| Download: ML19256B548 (1) | |
Text
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- G ut UNITED ST ATES f
o, NUCLEAR REGULATORY COMMISSION
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AT L ANT A. GEORGI A 30303 h,
In Reply Refer To:
JUL 6 1979 RII:JP0 50-302 Florida Power Corporation Attn:
W. P. Stewart, Ibnager Nuclear Operations P. O. Box 14042, 1611 Stop C-4 St. Petersburg, Florida 33733 Gentlemen:
Written The enclosed Bulletin 79-05C and 79-06C is forwarded to you for action.
responses are required.
If you desire additional information regarding this catter, please contact this office.
Sincerely, i
mm, s.
fig James P. O'Reilly Director
Enclosure:
- 2. Listing of IE Bulletins issued In Last Twelve Months
([C 790806095, b
JUL. 6197e
. Florida Power Corporation cc w/ enc 1:
G. P. Beatty, Jr.
Nuclear Plant Superintendent Post Office Box 1228 Crystal River, Florida 32629
UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
10555 July 26, 1979 IE Bulletin Nos.79-05C & 79-06C NUCLEAR INCIDENT AT THREE 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" portion of IE Bulletins79-05A, 79-06A and 79-06B, for all pressurized water reactors (PWRs).
Item 4.c of Bulletin 79-05A required all holders of operating licenses for Babcock & Wilcox designed PWRs to revise their operating procedures to specify t ha t, in the event of high pressure injection (HPI) initiation with reactor coolant pumps (RCPs) operating, at least one RCP per loop would remain operating.
Similar requirements, applicable to reactors designed by other PWR vendors, were contained in Item 7.c of Bulletin 79-06A (for Westinghouse designed plants) and in Item 6.c of Bulletin 79-06B (for Combustion Engineering designed plants).
Prior to the incident at Three Mile Island Unit 2 (TMI 2), Westinghouse and its licensees generally adopted the position that the operator should promptly trip all operating RCPs in the loss of coolant accident (LOCA) situation.
This Westinghouse position, has led to a serier of meetings between the NRC staf f and Westinghouse, as well as with other PWR vendors, to discuss this issue.
In addition, more detailed analyses concerning this matter 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 the RCPs can increase the mass lost through the break and prolong or aggravate the uncover-ing of the reactor core.
The damage to the reactor core at TMI 2 followed tripping of the last operating 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 is to trip all operat ing RCPs immediately, before significant voiding in the reactor coolant syst,' occurs.
Ac' ton To Be Taken By Licensees:
In order to alleviate the concern over delz LOCA, all holders of operating licenses fo DUPLICATE DOCUMENT following actions:
Entire document previously entered into system under:
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