PY-CEI-NRR-1516, Part 21 Rept Re Defects in MSIV Poppets Supplied by Atwood & Morrill Co,Inc.Intially Reported on 920522.Measures Will Be Established to Ensure That Adequate Repair Methods Are Employed During Future Repairs of Modified MSIV Poppets

Part 21 Rept Re Defects in MSIV Poppets Supplied by Atwood & Morrill Co,Inc.Intially Reported on 920522.Measures Will Be Established to Ensure That Adequate Repair Methods Are Employed During Future Repairs of Modified MSIV Poppets

ML20101F129
Person / Time
Site:	Perry
Issue date:	06/19/1992
From:	Lyster M CENTERIOR ENERGY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
REF-PT21-92 PY-CEI-NRR-1516, NUDOCS 9206240291
Download: ML20101F129 (3)

Text

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GNN g PERRY NUCLEAR POWER PLANT igoress' Michael D. Lyster E ER RO PERRY, OHIO 44081 VICE PRESIDENT NUCL. EAR L (216) 259-3737 June 19, 1992 PY-CEI/NRR-1516 L U. S. Nuclear Regulatory Commission -

Document Control Desk Vashington,-D. C. 20555 Perry Nuclear Power Plant Docket No. 50-440 10CFR21 Notification, Defects in MSIV Poppets Supplied by A&M

-Gentlemen:

<This letter is submitted pursuant to the requirements of 10CFR21.21(c)(3)(ii) to report defects in Main Steam Isolation Valve (MSIV) poppets supplied by Atwood and Morrill Company, Incorporated (A&M). An extensive evaluation was performed'to' determine the source of deviations observed in MSIV-poppets received at the Perry Nuclear Power Plant (PNPP). On May 21, 1992, the evaluation concluded-that- these deviations constituted defects under 10CFR21.

A preliminary notification regarding the subject defects was transmitted to the NRC Operations Center _ on May 22, 1992 by facsimile. -

Chronology A total of eleven (11) poppets were ordered from A&M as part of a design improvement for the MSIVs at the Perry Power Plant. Nine of eleven poppets vere = received during the three month period from September 5, to December 3, 1991.

On April 1, 1992, a linear indication was observed in the Stellite 21 hardfaced seating surface of a poppet identified _as serial-number (S/N) 5. A Nonconformance Report (NR) was issued to document the deficiency and the poppet was returned to A&M for repair. The remaining 8 poppets were visually inspected prior to April 5, 1992 and revealed no signs of cracking.

On April 8, 1992, at 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br />, a crack which ran across the seating surface and approximately 1/3 of the circumference in-the relief area was discovered on N By 1130 hours0.0131 days <br />0.314 hours <br />0.00187 weeks <br />4.29965e-4 months <br />, the crack had traveled approximately 1/2 the

$ poppet S/N 4 vithin the relief area. Subsequent visual and liquid circumference X . penetrant testing of "the other poppets revealed cracks in poppets S/N 6 and 9206240291 920619 PDR- ADOCK 05000440-S PDR Operotng Compones ja Cleveland Eiectne mummonng f]

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USNRC June 19, 1992 PY-CEI/NRR-1516 L k

S/N 12.- All poppets with identified cracking (S/Ns 4, 5, 6 and 12) were returned to A&M for repair. A hold was placed on the shipment of two poppets (S/N 2 and S/N 9)'vhich were still in the fabrication stage, pending an evaluation of the cracking problem. A&M vas requested to provide a root cause analysis to identify the source of the cracking and to provide justification to support the use et poppets vhich did not experience cracking.

Apparent Cause-The analysis performed by A&M concluded that the post-production cracking in the hardfaced material was caused by excessive build-up of residual stresses during repair activities.and/or a substantial increase in the overall thickness ,

of the Stellite 2* hardfacing.

LThe initial repairs made.to S/Ns 4, 5, and 6, during the production run,

' involved the entire removal of the original hardfacing and some of the base material. The re-velding was done entirely with Stellite 21. This resulted in the overall thickness of the new hardfacing being thicker than originally designed. Two initial repairs to S/N 12 involved localized repairs as opposed to. entire hardfacing removal. In summary, A&M did not tailor their repair methods towards preserving the original design hardfacing thickness during the

. production phase. It is also possible that the type of heat treatment given to the poppets prior.to hardfacing had an influence on limiting the capability of the poppets to tolerate multiple repairs.

Corrective Actions The absence of multiple veld repair histories and the preservation of the original design hardfacing thickness formed the basis for determining the acceptability for service of the poppets which did not experience cracking (S/Ns 3,'7, 8,.9, 10 and 11). Although poppet S/N 11 did not exhibit cracking, the poppet had experi aced one-major repair in the nose / seating area. Post veld heat treatment was performed to alleviate concerns regarding residual stresses which may have been present. Poppet S/N 9 vas also repaired utilizing post-veld heat. treatment to minimize residual stresses.

Poppet S/Ns 3, 7, 8, 9, 10 and 11 vere installed in the plant during Refuel

-Outage (RFO) 3, which ended on June 13, 1992. . An additional poppet S/N 4 was repaired by A&M and returned to PNPP on May 7, 1992. Poppets S/Ns 2, 5, 6 and 12 currently reside at A&M, pending satisfactory completion of repairs.

Heatires vill be established to ensure that-adequate repair methods are L employed-during future repairs of the modified MSIV poppets. These include a requirement to provide a documented evaluation of repairs as part of the receipt inspection process and vendor manual changes to ensure that future MSIV

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USNRC June 19, 1992 PY-CEI/NRR-1516 L poppet veld repairs include - propriate stress relief heat treatments when required. These measures vill be in place prior to the next scheduled refueling outage.-

Sincerely,

' $f Michae D. Lyster MDL:RVG:ss cc NRC Project Manager NRC Resident Inspector Office NRC Region III Administrator

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