LIC-12-0152, Response to Denial of Violation in NRC Inspection Report 05000285/2012002
| ML12312A109 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 11/06/2012 |
| From: | Prospero M Omaha Public Power District |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| LIC-12-0152, EA-12-095, IR-12-002 | |
| Download: ML12312A109 (3) | |
Text
Employment with Equal Opportunity 444 South 16th Street Mall Omaha, NE 68102-2247 LIC-12-0152 November 6, 2012 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001
References:
- 1. Docket Number 50-285
- 2. Letter from NRC (J. A. Clark) to OPPD (D. J. Bannister),
Fort Calhoun - NRC Integrated Inspection Report Number 0500028 5/2012002, dated May 11, 2012 (NRC-12-0049) (EA-2012-095) (ML12132A395)
- 3. Letter from OPPD (D. J. Bannister) to NRC (Document Control Desk), Response to NRC Inspection Report 05000285/2012002, EA-2012-095, dated June 11, 2012 (LIC-12-0080) (ML12181A022)
- 4. Letter from NRC (T. M. Blount) to OPPD (Lou Cortopassi), Denial of Violation in NRC Inspection Report 05000285/2012002, dated September 14, 2012 (NRC-12-0088) (EA-2012-095) (ML12258A293)
SUBJECT:
Response to Denial of Violation in NRC Inspection Report 05000285/2012002 In Reference 4, the Nuclear Regulatory Commission (NRC) transmitted the results of an independent review of t he documentation associated with violation 05000285/2012002-03, Failure to Meet Design Basis Requirements for Design Basis Flood Event. This violation is related to a previously issued Yellow finding regarding the ability to mitigate an external floodin g event at Fort Calhoun Station (FCS), Unit No. 1. Specifically, the Omaha Public Power District (OPPD) failed to translate design basis requirements for protection of the safety-related raw water system during a design basis flood for flood levels between 1,010 and 1,014 feet mean sea level (MSL) as identified in the Updated Safety Analysis Report (USAR).
As stated in Reference 3, OPPD has revised procedures to control raw water levels within the intake structure cells and installed temporary measures to protect the sluice gate motor operated valves (MOVs) from river-born debris.
Additionally, using the 10 CFR 50.59 process, OPPD will install a modification that will eliminate the need to re-position the intake structure sluice gates at flo od levels between 1,010 and 1,014 feet MSL. The current method of closing five of the six exterior sluice gates and positioning the remaining gate such th at a balance between river water i nflow and raw water p ump discharge will not be the method of maintaining the water level within the intake str ucture cells in the future. It is planned to use the existing trash r ack backwash lines to backflow river water by gravity into the intake structure cells through installation of new throttle valves downstream of th e trash rack grid.
After installation of the throttle valves, OPPDs flood response will require that the sluice gate s be
U. S. Nuclear Regulatory Commission LlC-12-0152 Page 2 closed to act as flood barriers and, once closed, the MOVs for the sluice gates will not be required.
This modification will be installed by May 1,2013 in preparation for the 2013 flood season.
OPPD recognizes that the inspection report details provide a discussion of water-born hazards (Le.,
floating tree or other large river debris) and the potential effect of these hazards on the plant's ability to position the exterior sluice gates. However, the violation does not specifically indicate that FCS is required to address such hazards at flood levels between 1,010 and 1,014 feet MSL nor that this is a part of the current licensing basis. Currently, there is no regulatory or industry guidance to establish or assess such hazards. With installation of the planned modification the throttle valves will be protected.
This letter contains a regulatory commitment that is summarized in the attached table.
If you should have any questions, please contact Mr. Bill Hansher at (402) 533-6894.
Sincerely, Michael J. Prospero Plant Manager
Attachment:
Table of Regulatory Commitments MJPfTWS/brh c:
E. E. Collins, Jr., NRC Regional Administrator, Region IV L. E. Wilkins, NRC Project Manager J. C. Kirkland, NRC Senior Resident Inspector
LIC-12-0152 Attachment Page 1 Regulatory Commitments Commitment Date AR Number A modification will be installed that will eliminate the need to re-position the intake structure sluice gates during flood levels between 1,010 and 1,014 feet MSL.
May 1, 2013 AR 55733