PNO-III-87-066A, on 870509,piping Elbows & Hangers Damaged by Alleged Water Hammer.Piping Elbows on Each End of 200-ft Run of Main Steam Line Piping Dropped 7 Inches.Indication Found on pipe-to-elbow Weld Downstream of MSIV B.Cause Unknown

PNO-III-87-066A:on 870509,piping Elbows & Hangers Damaged by Alleged Water Hammer.Piping Elbows on Each End of 200-ft Run of Main Steam Line Piping Dropped 7 Inches.Indication Found on pipe-to-elbow Weld Downstream of MSIV B.Cause Unknown

ML20214F169
Person / Time
Site:	Byron
Issue date:	05/14/1987
From:	Forney W, Warnick R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-87-066A, PNO-III-87-66A, NUDOCS 8705220434
Download: ML20214F169 (1)

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PRELIMINARY NOTIFICATION 0 EVENT OR UNUSUAL-0CCURRENCE--PNO-III-87-66A Date May 14,-1987 This' preliminary notification constitutes EARLY notice ,of events of POSSIBLE -safety cr public interest significance. The information is as initially received without vartfication or evaluation, and is basically all that is known by. the' Region III

staff on this date.

Facility: Commonwealth Edison Company Licensee Emergency Classification:

Byron ~ Unit 1 Notification of'an_ Unusual Event Byron, IL 61010 Alert Site Area Emergency Docket No. 50-454 General Emergency X Not Applicable

Subject:

WATER HAMMER IN MAIN STEAM LINE----(UPDATE)

Licensee-personnel have examined the damage to the IB Main Steam line as a result of the alleged water hammer on May 9, 1987. (See PNO-III-87-66)

The licensee has determined that piping elbows on each end of a 200-foot run of Main Steam Line piping dropped seven inches. The maximum deflection was 20 inches in the center of the 200-foot run.

In addition, 15 hangers were damaged (nine rigid supports and six snubbers). Magnetic-particle testing on 13 welds in the Main Steam Line B Loop and eight welds on the C Loop showed no significant indications. Thirteen hanger components are currently being examined.

Ultrasonic testing has found an indication on a pipe to elbow weld downstream of the B Main Steam Isolation Valve. Radiography testing is now in progress on this weld.

Seven snubbers have also been tested for operability. One has failed to stroke.

The licensee's architect-engineer is currently analyzing the data collected thus far. The spzcific cause of the event has not been determined, although a water hammer has not been ruled out. Other possibilities include stuck snubbers, a steam bubble collapse induced waterhammer, or hanger failure. '

i Rngion III (Chicago) has sent a piping inspector to the facility to inspect the damage.

Region III continues to monitor the licensee's course of action.

The State of Illinois will not be notified.

This updated information is current as of 3:30 p.m. (CDT), May 14, 1987.

CONTACT: W o nY M S 388-5590) 9 R. a c5(FTS388-5575)

DISTRIBUTION:

H. St. EDO NRR E/W Willste Mail: ADM:DMB

' Chairman Zech PA IE NMSS- DOT:Trans only Comm. Roberts ELD OIA RES Comm. Asselstine AE0D NRC Ops Ctr 4 W A Conar. Bernthal .

Comm. Carr SP -4NA Regional Offices ACRS SECY INP0 4 Rh!E ~ NSAC 4 %

CA RIII Resident 0ffice PDR Licensee: LO 42L (Corp. Office - Reactor Lic. Only) 9(

C g 2gg34 870514 Region III PNO-III-87-066_PDR Rev.: November 1986: