Bulletin 74-010B: Failures in 4-Inch Bypass Piping at Dresden-2
BL74010B UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555. JAN 24 1975 J. P. O'Reilly, Director, Region I N. C. Moseley, Director, Region II J. G. Keppler, Director, Region III E. M. Howard, Director, Region IV R. H. Engelken, Director, Region V IE BULLETIN NO. 74-10B - FAILURES IN 4-INCH BYPASS PIPING AT DRESDEN-2 The subject Bulletin should be dispatched for action to all BWR facilities of jet-pump design with operating license by close of business today. The Bulletin should also be dispatched for information to all other BWR facilities with operating license or construction permit and to all PWR facilities with operating license no later than close of business on January 27, 1975. The text of the Bulletin and draft letters to licensees are enclosed for this purpose. John G. Davis, Deputy Director for Field Operations Office of Inspection and Enforcement Enclosures: As stated . (Draft letter for action to all BWR facilities of jet-pump design with operating license) IE Bulletin 74-10B Gentlemen: Enclosed is IE Bulletin 74-10B, which amends the description of the circumstances discussed in RO Bulletin 74-10A and requests additional actions by you. Should you have questions regarding this Bulletin or the actions requested of you, please contact this office. Sincerely, Director Enclosure: IE Bulletin 74-10B Approved by GAO, B-180225 (R0072), clearance expires 7-31-77. Approval was given under a blanket clearance specifically for identified generic problems. . (Draft letter for information to all other BWR facilities with operating license or construction permit and to all PWR facilities with operating license.) IE Bulletin 74-10B Gentlemen: Enclosed is IE Bulletin 74-10B which is forwarded to you for information. No action is required of you if you do not have a boiling water reactor of jet-pump design with operating license. Should you have questions regarding this Bulletin, please contact this office. Sincerely, Director Enclosure: IE Bulletin 74-10B . IE Bulletin No. 74-10B Date: 1/24/75 FAILURES IN 4-INCH BYPASS PIPING AT DRESDEN-2 (REFERENCE: RO BULLETIN NOS 74-10, Dated 9/19/74 AND 74-10A, DATED 12/17/74) 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 previously (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.5. of Regulatory Guide 1.45) any reactor coolant leakage detection system indicates, within a period of 4 hours 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: a. Initiate plant shutdown immediately, and b. Determine the source of increased leakage prior to resuming operation. . c. If there is evidence of leakage from the 4-inch 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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