ML061660131
| ML061660131 | |
| Person / Time | |
|---|---|
| Site: | Mcguire, Brunswick, McGuire  |
| Issue date: | 06/13/2006 |
| From: | Abramovitz M NAK Engineering |
| To: | Ayres D, Blount T, Ian Jung Office of Nuclear Reactor Regulation, NRC/RGN-II |
| References | |
| 42637 | |
| Download: ML061660131 (3) | |
Text
-I 06/13/2006 U.S. Nuclear Regulatory Commission Operations Center Event Report Pae I General Information or Other (PAR)
Event#
42637 Rep Org: NAK ENGINEERING INC Notification Date I Time: 06/13/2006 15:29 (EDT)
Supplier: NORDBERG Event Date I Time: 06/13/2006 (PDT)
Last Modification: 06/13/2006 Region: 4 Docket #:
City: WINDSOR Agreement State: Yes County:
License #:
State: CA NRC Notified by: NAK ENGINEERING Notifications:
DAVID AYRES R2 HQ Ops Officer: MARK ABRAMOVITZ THOMAS BLOUNT IRD Emergency Class: NON EMERGENCY IAN JUNG NRR 10 CFR Section:
21.21 UNSPECIFIED PARAGRAPH 10 CFR PART 21 NOTIFICATION - DEFECTIVE NORDBERG EMERGENCY DIESEL GENERATOR VALVE SEAT INSERTS The manufacturer provided the following information via facsimile:
"Significant Safety Hazard regarding the potential of Nordberg Valve Seat Inserts (VSI) to 'drop' from the bore of the cylinder head into the cylinder with probable resulting damage to the cylinder head, power valves, piston, cylinder liner, exhaust manifold and turbocharger which could result in the loss of the intended 'Safety Function' of the EDG.
"There exists a potential problem with the original specification for the specified value of interference fit of the inlet and exhaust Valve Seat Insert (VSI) in the area between the cylinder head bore and the VSI."
Two sites, Brunswick and McGuire, had the defective parts with Brunswick already having changed out the affected parts.
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5813 SKYLANE BLVD., WINDSOR, CA 95492 TELEPHONE: (707)542-9996 FAX: (707) 542-6666 Document Control Desk Nuclear Regulatory Commission Operations Center Washington, DC 20555 Fax: 301-816-5151 June 13, 2006 10 CFR Part 21 Reporting Re: Nordberg Diesel Emergency Diesel Generators
Subject:
Significant Safety Hazard regarding the potential of Nordberg Valve Seat Inserts (VSI) to "drop" from the bore of the cyliuder head into the cylinder with probable resulting damage to the cylinder head, power valves, piston, cylinder liner, exhaust manifold and turbocharger which could result in the loss of the intended "Safety Function" of the EDG In accordance with the requirem ents of Title 10, Chapter 1, Code of Federal Regulations, Part 21, NAK Engineering, Inc. hereby notifies the commission ofa potential defect or condition in a component of the Nordberg Diesel Emergency Diesel Generator (EDG)
Tbere exists a potential problem with the original specification for the specified value of interference fit of the inlet and exhaust Valve Seat Insert (VSI) in the area between the cyliuder head bore and the VSI.
Utilitv Site Serial Number(s)~
Model Progress Energy Brunswick Nuclear Project***
1030-1328)1331 FS 1316HSC
- Note: Progress Energy has completed the change out of all VSI's with the new interference fit requirements in all the Brunswick Nordberg units after experiencing a "dropped" VSI several years ago.
Duke Energy MeGuire Nuclear Station 1030-1270/1273 FS 1316HSC Valve Seat Insert Interference Fit Upgrade and Recommendation Part Numbers: All 8477-27XX Series Valve Seat Inserts with Counter-bored cylinder heads (Insert Part Number(s): 8477-2740, 8477-2772, 8477-2779, 8477-2782 etc.... ) for use on Nordberg Cylinder Heads 4262-6907 and 4262-6908.
Problem: Nordberg Manufacturing Company originally specified the Valve Seat Insert interference fit of.0015" to.003" from the seat bores on cylinder heads to the Valve Seat Insert. There have been noted failures both on Nuclear (Brunswick EDG's) and various commercial of the Nordberg Valve Seat Inserts dropping into the cylinder resulting in damage. This "dropping" is due to insufficient interference fit.
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JU11.1,:J.e-W0b I U: I eHM NRK ENGINEERING 707-542-6666 NO. 564 P. 2 NAK Engineering Inc.
5813 SKYLANE BLVD., WINDSOR, CA 95492 TELEPHONE: (707)542-9996 FAX: (707) 542-6666 Page 2 of 2 NAK Engineering, Inc., the current Nordberg OEM has revised the Original Nordberg Specification for the required interference fit. The recommendation is that all Valve Seat Inserts have an interference fit of
.0025" to.004" into the cylinder head bore. The expanded interference will allow the scat to be held more securely within the seat bore of the lhead, but not so tight as to induce potential cylinder head cracking.
Recommendation: It is recommended that seats be fitted to the cylinder head bore with the new specification during maintenance. Machining of the cylinder head is sometimes required to true up the bore.
For this, Valve Seat Inserts are available in various oversized dimensions should the cylinder head valve seat bores require such machining.
GENUINE NORDBERG' ENGINE PARTS 06/13/.2006 TE 13:42
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