Bulletin 75-05: Operability of Category I Hydraulic Shock and Sway Suppressors
BL75005 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 April 14, 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 75-05 - OPERABILITY OF CATEGORY I HYDRAULIC SHOCK AND SWAY SUPPRESSORS The subject Bulletin should be dispatched for action to all power reactor facilities with operating license or construction permit by close of business on April 14, 1975. The text of the Bulletin and draft letter to licensees are enclosed for this purpose. John G. Davis Deputy Director for Field Operations Office of Inspection and Enforcement Enclosures: As stated Distribution: See page 2 . (Draft letter for action to all power reactor facilities with operating license or construction permit) IE Bulletin No. 75-05 Gentlemen: Enclosed is IE Bulletin No. 75-05 which requires action by you with regard to your power reactor facility(ies) with an operating license or construction permit. Also enclosed are copies of RO Bulletins 73-3 and 73-4 which are referenced in IE Bulletin 75-05. Should you have questions regarding this Bulletin or the actions required of you, please contact this office. Sincerely, Director Enclosures: IE Bulletin No. 75-05 RO Bulletin Nos. 73-3 and 73-4 Approved by GAO, B-180225 (R0072), clearance expires 7-31-77. Approval was given under a blanket clearance specifically for identified generic problems. . IE BULLETIN NO. 75-05 April 14, 1975 OPERABILITY OF CATEGORY I HYDRAULIC SHOCK AND SWAY SUPPRESSORS DESCRIPTION OF CIRCUMSTANCES: The Metropolitan Edison Company notified the Region I Office of Inspection and Enforcement by telephone on March 21, 24 and 25, 1975, of the finding of eight inoperable hydraulic shock suppressors on the main steam lines inside containment at the Three Mile Island facility. The licensee reported that these suppressors were removed for overhaul (seal replacement) and testing during a planned maintenance program. The suppressors were determined to be inoperable (suppressor lockup could not be achieved) during, piston displacement tests performed by the licensee. The tests were performed on a test rig which actuates the piston with air pressure. These suppressors, representing equipment originally installed at the facility, were specified to achieve lockup at a velocity not exceeding 10 in. per minute. The test rig at the facility was reported to have a capability of testing at velocities up to 50 in. per minute. The specific cause of the reported failures has not been determined. Spare suppressors were installed as replacements after their acceptability was determined by the licensee by test. For your information, RO Bulletins 73-3 and 73-4, dated July 27, 1973 and August 17, 1973 respectively (copies enclose) discuss some prior experience concerning the operability of hydraulic suppressors. In general, the installation of hydraulic suppressors provides a system for the restraint of Category I systems and components against excessive movement during seismic and fluid system transient conditions. Although in such a restraint system the failure or inoperability of a single suppressor would not normally defeat the design function of the restraint system, it is desirable to provide for the periodic testing of a representative sample from the total population of suppressors to assess the operational capability of the restraint system on a continuing basis. ACTION TO BE TAKEN BY LICENSEES: 1. For all power reactor facilities with an operating license: Review the design and installation of your hydraulic restraint systems, and provide the following information to this office in writing within 30 days of the date of this Bulletin: a. The design requirements which the various suppressors are intended to meet, such as velocity, acceleration, load, etc. Also, indicate the margin available between the . -2- design requirements and the requirements specified for purchase of these components. b. Describe the testing of the hydraulic suppressors conducted by you or your supplier (s) prior to installation to assure their operation in accordance with design requirements. c. Describe the surveillance (including testing) programs now underway or planned by you to assure continued operability of the hydraulic suppressors under the design. Conditions throughout the life of the facility. 2. For all power reactor facilities with a construction permit: Report to this office in writing within 60 days of the date of this Bulletin or prior to completion of preoperational testing, whichever is earlier, the information requested in Items 1.a. thru 1.c. above. A copy of your response to items 1 and 2 above should also be sent to: Assistant Director for Construction and Operations, Office of Inspection and Enforcement, USNRC. Washington, D. C. 20555.
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