ML071350245
| ML071350245 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 05/03/2007 |
| From: | Lucas J Progress Energy Carolinas |
| To: | Document Control Desk, NRC/NRR/ADRO |
| References | |
| GL-07-001, RNP-RA/07-0018 | |
| Download: ML071350245 (5) | |
Text
Progress Energy Serial: RNP-RA/07-0018 MAY 0 3 2007 United States Nuclear Regulatory Commission ATTN: Document Control Desk 11555 Rockville Pike Rockville, Maryland 20852 H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET NO. 50-261/LICENSE NO. DPR-23 RESPONSE TO NRC GENERIC LETTER 2007-01, "INACCESSIBLE OR UNDERGROUND POWER CABLE FAILURES THAT DISABLE ACCIDENT MITIGATION SYSTEMS OR CAUSE PLANT TRANSIENTS" Ladies and Gentlemen:
On February 7, 2007, NRC Generic Letter 2007-0 1, "Inaccessible or Underground Power Cable Failures that Disable Accident Mitigation Systems or Cause Plant Transients," was issued requesting that licensees provide a response within 90 days. Carolina Power and Light Company, also known as Progress Energy Carolinas, Inc., is providing the response for H. B.
Robinson Steam Electric Plant, Unit No. 2, in Attachment II to this letter.
Attachment I provides an Affirmation in accordance with the provisions of Section 182a of the Atomic Energy Act of 1954, as amended, and 10 CFR 50.54(f).
There are no commitments associated with this letter.
If you have any questions concerning this matter, please contact Mr. C. T. Baucom at (843) 857-1253.
Sincerely, Jan F.
eas Manager - Support Services - Nuclear ANH/anh Progress Energy Carolinas, Inc.
Robinson Nuclear Plant 3581 West Entrance Road Hartsville, SC 29550 7
2*
United States Nuclear Regulatory Commission Serial: RNP-RA/07-0018 Page 2 of 2 Attachments:
I.
II.
Affirmation Response to NRC Generic Letter 2007-01, "Inaccessible or Underground Power Cable Failures that Disable Accident Mitigation Systems or Cause Plant Transients" c:
Dr. W. D. Travers, NRC, Region II Ms. L. M. Regner, NRC, NRR NRC Resident Inspector
United States Nuclear Regulatory Commission Attachment I to Serial: RNP-RA/07-0018 Page I of 1 AFFIRMATION The information contained in letter RNP-RA/07-0018 is true and correct to the best of my information, knowledge, and belief; and the sources of my information are officers, employees, contractors, and agents of Carolina Power and Light Company, also known as Progress Energy Carolinas, Inc. I declare under penalty of perjury that the foregoing is true and correct.
Executed On:
2, 0
.T. D. Walt Vice President, HBRSEP, Unit No. 2
United States Nuclear Regulatory Commission Attachment II to Serial: RNP-RA/07-0018 Page 1 of 2 H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 RESPONSE TO NRC GENERIC LETTER 2007-01, "INACCESSIBLE OR UNDERGROUND POWER CABLE FAILURES THAT DISABLE ACCIDENT MITIGATION SYSTEMS OR CAUSE PLANT TRANSIENT"S"
Background
NRC Generic Letter (GL) 2007-01, "Inaccessible or Underground Power Cable Failures that Disable Accident Mitigation Systems or Cause Plant Transients," requires that, within 90 days of the issuance of the Generic Letter, all addressees submit to the NRC the following information:
(1)
Provide a history of inaccessible or underground power cable failures for all cables that are within the scope of 10 CFR 50.65 (the Maintenance Rule) and for all voltage levels. Indicate the type, manufacturer, date of failure, type of service, voltage class, years of service, and the root causes for the failure.
(2)
Describe inspection, testing and monitoring programs to detect the degradation of inaccessible or underground power cables that support EDGs, offsite power, ESW, service water, component cooling water and other systems that are within the scope of 10 CFR 50.65 (the Maintenance Rule).
In a letter from James H. Riley (Nuclear Energy Institute [NEI]) to plant administrative contacts, dated March 16, 2007, NEI provided guidance for developing a response to GL 2007-01. The NRC accepted the guidance, with certain modifications, in a letter from Michael J. Case (NRC) to James H. Riley, dated April 13, 2007. The responses provided were developed using the NEI guidance as modified by the NRC letter.
The following information is provided in response to Items (1) and (2) for the H. B. Robinson Steam Electric Plant (HBRSEP), Unit No. 2.
RESPONSE (1):
HBRSEP, Unit No. 2, has performed a review of plant document history to identify inaccessible or underground power cable failures. The search identified six failures, four of which were attributed to inadvertent damage during construction work. One cable failure was attributed to a settling building structure, and one cable failure was most likely due to an underground splice failure, although the precise failure mechanism is indeterminate.
Due to the age of the plant and regulatory requirements in existence at the time the plant was licensed, certain data could not be determined. These table values are marked "indeterminate."
United States Nuclear Regulatory Commission Attachment II to Serial: RNP-RA/07-0018 Page 2 of 2 Date of Voltage Voltage Years of Type Manufacturer Failure Type of Service Class Range Service Cause of Failure Non-Energized Cable was damaged shielded Rome Cable 12/27/1984 Deep Well Pump "B" 600 460 Indeterminate during excavation.
Non-Do-energized Cable was damaged shielded Indeterminate 10/23/1987 Service Water Valve V6-12A 600 460 Indeterminate during excavation.
Non-Cable was damaged shielded Indeterminate 12/2/1990 Service Water 600 460 or 120 Indeterminate during excavation.
De-energized Non-EDG Fuel Oil Cable was damaged shielded Indeterminate 10/16/2002' Transfer Pump "B" 600 460 Indeterminate during excavation.
Cable was damaged by Non-a settling building shielded Indeterminate 19802 Service Water 600 460 or 120 Indeterminate structure.
Indeterminate, but most likely caused by Non-Energized underground splice shielded Rome Cable 9/17/2004 Deep Well Pump "B" 600 460 Indeterminate failure.
'Date is approximate; cable damage was discovered when the component was re-energized.
2 Time frame is approximate; this occurrence is based primarily on recollections of longer-term plant employees.
RESPONSE (2):
HBRSEP, Unit No. 2, procedure PM-479, "Motor Testing," is used to perform off-line testing of motor winding insulation resistance and circuit resistive balance of plant electric motors. This testing is performed for critical and important motors, and is typically conducted from the motor control center (MCC) breaker to determine the health of the motor and the associated power cable. PM-479 includes the "AC standard" test which consists of low resistive DC bridge, inductive AC bridge, AC capacitance to ground, and DC megohm to ground tests. Dielectric absorption, polarization index, stepped DC hi-pot, and rotor influence check may also be performed, if deemed necessary. Additional guidance and basis for preventative maintenance (PM) tasks for medium and low voltage electric motors is provided by the PM Basis document, NGG-PMB-MOT-0l, "NGG Equipment Reliability Template Medium and Low Voltage Electric Motors." Procedure MMM-053, "Electrical Installation," directs that multi-conductor cable reels be meggered and tested for continuity upon receipt.
Engineering review of inaccessible and underground power cables within the scope of NRC Generic Letter 2007-01 found that underground safety-related service water cables to the intake structure are routed through manholes that allow visual examination for cable degradation.
These manholes have sump pumps or drainage holes to minimize submergence.