ML20037B385
| ML20037B385 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Zion, LaSalle  |
| Issue date: | 01/27/1975 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Brian Lee COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 8009240828 | |
| Download: ML20037B385 (1) | |
Text
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URITED SVATES NUCLEAR REGULATORY COMMISSION DIRECTORATE OF REGULATORY OPERATIONS REGION lli 799 ROOSEVELT RO AD GLEN ELLYN ILLINOIS 60137 January 27, 1975 Comanonwealth Edison Company Docket No. 50-10 ATDI: Mr. Byron Lee, Jr.
Docket No. 50-295 Vice President Docket No. 50-304 P.O. Box 767 Docket No. 50-373 Chicago, T11tnais 60690 Docket No. 50-374 Gentlemen:
Fnelneed is IE Bulletin No.74-10B which is forwarded to you for information.
Should you have questions regarding this Bulletin, please contact this office.
Sincerely yours, James G. Keppler Regional Director
Enclosure:
IE Bulletin No.74-10B bec: _DR Central Files RO Files PDR Local PDR Anthony Roisman OGC, Beth, P-506A I
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c-s January 27, 1975 IE Bulletin No.74-10B FAILURES IN 4-INCH BYPASS PIPING AT'DRESDEN '
(
REFERENCE:
RO BULLETINS NO. 74-10, DATED SlPTEMBER 19, 1974 AND NO.74-10A, DATED DECEMBER 17, 1974)
DESCRIPTION OF CIRCUMSTANCES (AMENDED):
Cracks similar to those described in RO Bulletins 74-10 and 74-10A have been revealed during reexamination of the 4-inch bypass piping at five boiling water reactor facilities (including Dresden-2) since mid-December 1974. All the facilities are of jet-pump design.
In each instance where cracks have been revealed, the same welds had been examined pre-viously (during September-November 1974) and no cracks were revealed at that time.
A special study group, comprised of key technical members of the Nuclear Regulatory Commission staff, is currently studying the causes of the cracks which have been experienced.
Consultants from other government agencies are also participating in the study.
In the interim, pending recommendations of the Commission's special study group, additional actions are necessary by licensees to insure continued close surveillance of reactor coolant leakage.
ACTIONS REQUESTED OF LICENSEES (AMENDED):
For all boiling water reactor facilities of jet-pump design with operating license:
1.
Upon completion of those actions described in RO Bulletin 74-10A, implement the following reactor coolant leakage detection program:
If (within the sensitivity specified in paragraph C.S. of Regulatory Guide 1.45) any reactor coolant leakaga detection system indicates, within a period of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or less, either an increase in unidentified leakage to twice the determined normal rate of unidentified leakage or an increase in the rate of unidentified leakage by two (2.0) gpm or more:
Initiate plant shutdown immediately, and a.
b.
Determine the source of increased leakage prior to resuming operation.
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If there is evidence of leakage from the 4 #nch bypass piping, reexamine (by ultrasonic or other suitable volumetric inspection technique), all accessible welds in the bypass piping lines.
(In no case, however, shall the rate of leakage exceed that specified in the technical specifications without those actions required by the technical specifications being taken.)
2.
Notify this office, in writing within 10 days of your receipt of this Bulletin, of your intent to implement the actions described in 1.,
above.
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