ML20147E512

Insp Rept 99900100/97-01 on 970226.No Violations or Deviations/Noncompliance Noted.Major Areas Inspected:Root Cause Analysis That Limitorque Corp Performed on Smb Size 1 MOV Actuator to Determine Cause of Failure

ML20147E512
Person / Time
Issue date:	03/11/1997
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20147E507	List: ML20147E502 ML20147E512
References
REF-QA-99900100 NUDOCS 9703140177
Download: ML20147E512 (5)

Text

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U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR REACTOR REGULATION Report No.: 99900100/97-01 Organization: Limitorque Corporation 5114 Woodall Road Lynchburg, Virginia 24506-1318

Contact:

R. Segen, Director, Quality Assurance Limitorque Corporation 5114 Woodall Road Lynchburg, Virginia 24506-1318 (804) 528-4400 Nuclear Industry: Manufactures, services and provides replacement Activity components and sub-assemblies for its motor-operated valve actuators.

Date: February 26, 1997 Inspectors: Kamalakar R. Naidu, Senior Reactor Engineer i Joseph J. Petrosino, Q.A. Specialist l

Approved by: G. C. Cwalina, Chief Vendor Inspection Section (VIS) 1 Special Inspection Branch Division of Inspection and Support Programs l Office of Nuclear Reactor Regulation j l

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I 9703140177 970311 '

PDR GA999 ENVLMIT 99900100 PDR

During this inspection, the NRC inspectors reviewed Limitorque s root cause analysis, inspected the worm shaft r1! 'tch gear and collected additional information to evaluate further action.

L According to Oyster Creek's Deviation Report (DVR 96-870), the failed worm shaft clutch gear in question was supplied by Sigma, Inc. The gear was manufactured by C. I. Supply Company. The gear was perchased by Oyster Creek to replace a failed gear in a nonsafety-related actuator. Oyster Creek states that only parts and operators provided directly frora Limitorque are used in safety-related applications, however, several nonsafety-related actuators could contain parts that were not provided by thr. Original Equipment Manufacturer (OEM).

DVR 96-870 indicates that Oyster Creek experienced two failures of nonsafety-related Limitorque operators due to worm shi.ft clutch gear problems. The operators had been procured from Power Equipment Supply Company. The first

! failure resulted in a replacement gear being installed with an original Limitorque gear from the Oyster Creek warehouse. The second failure caused Oyster Creek to purchase the gear in question from Sigma.

3.2 Limitoraue Root Cause Analysis 1

a. Insoection Scone 1

\

Evaluate the root cause analysis performed by Limitorque on the worm shaft l clutch gear that failed to operate at Oyster Creek. Determine the potential j i

I for other similar nonconforming parts to be installed in safety-related  ;

applications in the nuclear industry. '

i b. Observations and Findlagi The inspectors reviewed the root cause analysis performed by Limitorque on the worm shaft clutch gear that failed at Oyster Creek (see figures 1 and 2).

Limitorque subjected this gear to various examinations and determined that:

The motor clutch gear cam pin staking operation had been omitted.

The worm shaft clutch gear lugs were not heat treated. ~

The gear teeth were inappropriately shaped and not shaved.

I There were a variety of other non-serious disparities in the geometry of i the part.

Based on the alsove results, Limitorque determined that it had not manufactured

the gear and that it was a " counterfeit."

During a plant tour, Limitorque personnel demonstrated the machinery used to hob and shave gear teeth and to precisely measure the resulting tooth profile.

Limitorque personnel informed the inspectors that they do not use any I

subcontractors to manufacture the worm shaft clutch gear and stated that they had no information on other potentially " counterfeit" or nonconforming parts.

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1 l The inspectors observed that Limitorque utilized Procedure QAP 13.2,

" Reporting of Defects for Safety Related Equipment," to document its evaluation on Form L-345; Limitorque concluded that the matter was not l reportable to the NRC pursuant to Part 21. Even though it considered the l

matter was not reportable, Limitorque concluded that the worm shaft clutch gear assembly was inferior in design, was not suitable for the intended application, and that the non-0EM part would have a short service life terminating in failure with associated consequences depending upon the criticality of the application. Since the suspect worm shaft clutch gear can be used in Limitorque's SMB, SB, SBD, or HBC type actuators installed in l safety-related applications, a substantial safety hazard could be created.

Therefore, in a letter dated January 27, 1997, Limitorque informed the NRC.

c. Conclusion The root cause evaluation was well documented, complete and thorough.

Although not required, in a letter dated January 27, 1997, Limitorque informed all nuclear power plants of the discovery of a potential condition concerning the suspect gear so that the plants could evaluate the issue for applicability to their plants.

4. PERSONS CONTACTED a I. E. Wilkinson, Director, Engineering a+R.D. Segen, Director, Quality Assurance a+P.G. McQuillan, Manager, Special Projects a+Wm. J. Miluszusky, Quality Assurance

• Denotes attendance at the entrance meeting on February 26, 1997.

+ Denotes attendance at the exit meeting on February 26, 1997.

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Figure 2 - Worm Shaft Clutch Gear (Gear Tooth) 1 4

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