LIC-13-0106, Control Element Drive Mechanism Housing Reliability (License Renewal Commitment No. 6)
| ML13225A004 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 08/08/2013 |
| From: | Cortopassi L Omaha Public Power District |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LIC-13-0106 | |
| Download: ML13225A004 (2) | |
Text
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m Wm m-Omaha Public Power Distdct 444 South 16& Street Mall Omaha, NE 68102-224 7 August 8, 2013 LIC-13-0106 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001
References:
- 1.
Docket No. 50-285
- 2.
Letter from OPPD (S. K. Gambhir) to NRC (Document Control Desk),
Responses to Potential Open Items for the Review of the License Renewal Application for Fort Calhoun Station, Unit 1, dated March 14, 2003 (ML030790091) (LIC-03-0035)
- 3.
Letter from OPPD (R. L. Phelps) to NRC (Document Control Desk), Fort Calhoun Station (FCS) Control Element Drive Mechanism (CEDM) Housing Reliability Management, dated October 15, 2001 (ML013410517) (LIC 0095)
- 4.
Letter from OPPD (R. T. Ridenoure) to NRC (Document Control Desk), Fort Calhoun Station (FCS) Discussion of Control Element Drive Mechanism (CEDM) Housing Reliability, dated January 25, 2002 (ML020510063) (LIC-02-0007)
Subject:
Fort Calhoun Station (FCS) Control Element Drive Mechanism Housing Reliability (License Renewal Commitment No. 6)
As stated in License Renewal (LR) Commitment No. 6 described in Section 15.4 of the Updated Safety Analysis Report (USAR), the Omaha Public Power District (OPPD) committed (Reference 2) to apply activities resulting from the Control Rod Drive (CRD) Material Reliability Management Plan to manage aging of control element drive mechanism (CEDM) housings. OPPD also committed to submit the revised Inservice Inspection (ISI) aging management programs (AMP) for NRC review and approval before the period of extended operation, which begins at Midnight on August 9,' 2013.
OPPD has reviewed its response to POI-8(f) in Reference 2 and LR Commitment No. 6 and has determined that the information contained therein regarding the ISI AMP for the CEDM housings remains valid. Therefore, it is unnecessary to seek NRC approval for changes to the ISI Program regarding management of CEDM aging.
In 2001, because of cracking in CRD mechanism housings at other nuclear power plants, OPPD stated (Reference 3) that it would continue to monitor industry operating experience (OE) to stay informed of developments in this area. In 2002, OPPD noted (Reference 4) that the highest risk component for transgranular stress corrosion cracking (TGSCC) was the j-groove weld on the CEDM seal housings. As a result, OPPD performs inspections of a sample of CEDM seal housings during refueling outages.
It should be noted that OPPD replaced the CEDM upper housings when the reactor vessel head was replaced in 2006.
Based on industry OE, the new, improved design of the CEDM upper housing reduces the number of areas that had previously experienced failures. For example, the redesigned CEDM upper housing has no ID weld overlay and one less butt weld than was present in the original design. Since their replacement in 2006, no indications of TGSCC have been found on the CEDM upper housings.
Employment with Equal Opportunity
U. S. Nuclear Regulatory Commission LIC-13-0106 Page 2 No additional commitments to the NRC are contained in this letter.
If you have any additional questions, or require further information, please contact Mr. Bill R.
Hansher at (402) 533-6894.
Sincerely, Louis P. Cortopassi Site Vice President and CNO LPC/KGM/mle c:
S. A. Reynolds, Acting NRC Regional Administrator, Region IV J. M. Sebrosky, NRC Senior Project Manager L. E. Wilkins, NRC Project Manager J. C. Kirkland, NRC Senior Resident Inspector