ML20207N435

Discusses Recent Evaluation of Snubber Failures at Two Facilities W/Potential to Significantly Impact Operability of Class 1 Piping Sys.Review Needed to Assure Proper NRC Attention Given to Types of Piping Sys Support Problems

ML20207N435
Person / Time
Site:	Dresden, Davis Besse, 05000000
Issue date:	06/27/1985
From:	Spessard R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:	Jordan E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
Shared Package
ML20204G677	List: ML20204G673 ML20207N311 ML20207N370 ML20207N393 ML20207N435 ML20207N455
References
FOIA-86-729 NUDOCS 8701140213
Download: ML20207N435 (2)

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,[ ,, NUCLEAR REGULATORY COMMISslON a REcson its T3# i Q(; \ f 799 ROOSEVELT RO AO g /g CLEN ELLYN, ILUNOIS 60137 June 27, 1985 MEMORANDUM T0: E. L. Jordan, Director, Division of Emergency Preparedness and Engineering Response, Office of Inspection and Enforcement FROM: R. L. Spessard, Director, Division of Reactor Safety Region III

SUBJECT:

REPORTABILITY OF PIPING SYSTEM SUPPORT COMP 0NENT FAILURES (AITS F03033785)

Region III recently evaluated snubber failures at two facilities which had the potential to significantly impact the operability of Class 1 piping systems.

Although the licensees did not consider these snubber failures to be reportable based on the provisions of 10 CFR 50.73, the licensees reported (for informa-tion) them because of' previous snubber failures and because they knew we had an interest in piping system support component failures. We do not disagree with the licensee's interpretation of the reportability of these failures under the provisions of 10 CFR 50.73; however, it is our belief that there should be a requirement for the NRC to be promptly notified when a system physical interference, water hamer, or other condition causes a piping system support component to fail.

The following brief descriptions of the snubber failures we recently evaluated will give you an appreciation of why we believe such matters should be reportable:

During the last refueling outage at Davis-Besse, a 3 Kip hydraulic snubberinstalledonthepressurizersurgeline(ClassIsystem)was observed to have a broken piston rod end. This same snubber was observed to be pulled away from the concrete wall during the previous refueling outage. The licensee determined that the cause of the problem was interference with the piping thermal movement. The licensee inspected this congested area to ensure adequate clearances existed between

( equipment and piping components. -

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E. L. Jordan 2 June 27, 1985 During the last refueling o.utage at Dresden Unit 2, a number of 10 Kip mechanical snubbers installed on the main steam lines (Class 1 system) were found iroperable and were subsequently determined to be damaged internally. Several of these same snubbers along with other 10 Kip mechanical snubbers were found inoperable and damaged internally during the previous refueling outage. The exact cause of the snubber damage is unknown, however, the damage is believed to be the result of a -

hydrodynamic overload caused by a water slug that was formed during the plant shutdown fast flooding operation. The licensee inspected the

, piping, suppo.rts, and related structures and performed further testing, hot walkdown measurements, and analytical evaluations.

'We request that you review this matter to determine if an additional reporting mechanism is needed to assure proper NRC attention is given to these types of piping system support problems.

If you have any questions concerning this matter, please contact me or Mr.D.H.Danielson(FTS 388-5610) of my staff.

Y -

R. L. Spessard, Director .

Division of Reactor' Safety cc: J. G. Keppler, RIII C. E. Norelius, RIII -

S. Ebneter, RI P. R. Bemis, RII R. P. Denise, RIV D. F. Kirsch, RV l

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