United States Nuclear Regulatory Commission - Protecting People and the Environment

Morning Report for April 5, 2006

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Part 21 2006-0005-00: Defective Residual Heat Removal (RHR) Check Valve at Diablo Canyon Power Plant


Dockets: 05000323

License No: DPR-82

MR Number: H-2006-0007
Date: 03/31/2006

Source Document: Call / Fax from Licensee

Reviewer: Omid Tabatabai


In accordance with 10 CFR 21.21(d)(1), Pacific Gas and Electric (PG&E) notified the NRC of a defective component received from Flowserve, Flow Control Division, in Raleigh, NC, but not installed at Diablo Canyon Power Plant (DCPP). The component is an 8-inch tilting disk check valve that was procured for installation in the Residual Heat Removal (RHR) System during the Unit 2 refueling outage (2R13) scheduled to begin on 04/17/06.

On 03/02/06, the defect was identified at DCPP during post-receipt bench testing and involved incorrect disc dimensions that caused the disc to stick in the valve bonnet (i.e., in the open position). This would have prevented the valve from performing its intended safety function of closing to prevent pump-to-pump interaction when both RHR pumps are running. Note: these check valves were installed in response to NRC Bulletin 88-04, 'Potential Safety Related Pump Loss.' Failure of this check valve, had it been installed, could have resulted in the loss of one RHR train on Unit 2, which could impact the ability to shut down the reactor and maintain it in a safe shutdown condition.

On 03/08/06, PG&E notified Flowserve of the defect via Supplier Audit Finding Report #060670010 and requested corrective actions be taken.

On 03/13/06, Flowserve concluded that the defect was caused by disc design error and test procedure error.

On 03/16/06, Flowserve initiated Quality Problem Corrective Action Plan #169, in which they concluded a Part 21 evaluation was not required.

However, on 03/31/06, PG&E Vice President, Diablo Canyon Operations and Station Director, determined that the defect does met the 10 CFR 21.21 reporting requirements.

PG&E initiated purchase of the 600 lb, stainless steel check valve on 06/02/05, and does not know whether any others have been manufactured by Flowserve. The valve was manufactured in accordance with Vendor Assembly Drawing W9023267 and ASME Section III, Subsection NC, 1989 Edition.

PG&E subsequently repaired the check valve in accordance with instructions provided in a Flowserve letter to PG&E, dated 03/16/06. The valve has now passed inspection and bench testing and the licensee plans to install it during the upcoming Unit 2 refueling outage (2R13).

The source of the above information is Licensee Event Notification: EN 42459, reported on 3/31/2006 by PG&E.


Name Office Abbrev Phone No E-Mail
TABATABAI, OMID NRR (301) 415-6616 OTY@nrc.gov
KING, MARK S NRR (301) 415-1150 MSK1@nrc.gov


Part 21 2006-0006-00: Whiting Crane Overstress Condition


Monee, Illinois

License No:

MR Number: H-2006-0008
Date: 04/03/2006

Source Document: E-MAIL from Licensee

Reviewer: Mark King


The following is a summary of information provided by the crane manufacturer via email:

On March 30, 2006, as part of a crane design analyses and study, Whiting Corporation identified two overstress conditions. One is on the Girder End connection of a low head room bridge and one on a single fastener in a main hoist gear case application. It is recommended that the affected cranes at the facilities listed below be restricted to 50 percent capacity for the over stressed end connection and 50 percent or 85 percent capacity for the suspected over-stressed bolt until such time as the fastener or end connection can be inspected and evaluated or replaced. The following list identifies the nuclear facilities where the bridges and trolleys are suspected to be affected, as identified by the Whiting Corporation:

Region 1 Plants: Indian Point, Oyster Creek, Three Mile Island, Seabrook

Region 2 Plants: Oconee, McGuire, Shearon Harris, St. Lucie, Catawba

Region 3 Plants: D. C. Cook

Region 4 Plants: Cooper, Waterford, Grand Gulf, San Onofre, Palo Verde, Columbia Generating Station

Note: Whiting Corporation is attempting to contact the customers directly to notify them of this circumstance.

Previous Whiting Corporation crane related Part 21 information can be viewed at our NRC website for Part 21's:

or directly from the links below:


Name Office Abbrev Phone No E-Mail
TABATABAI, OMID NRR (301) 415-6616 OTY@nrc.gov
KING, MARK S NRR (301) 415-1150 MSK1@nrc.gov
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