CP-201100609, Response to Request for Additional Information, Relief Request No. C-6 and C-7
| ML11119A005 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 04/21/2011 |
| From: | Flores R Luminant Generation Co, Luminant Power |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| CP-201100609, TAC ME5215, TAC ME5216, TXX-11053 | |
| Download: ML11119A005 (4) | |
Text
Rafael Flores Senior Vice President
& Chief Nuclear Officer Rafael.Flores@Luminant.com Luminant Power P 0 Box 1002 6322 North FM 56 Glen Rose, TX 76043 Lum inantT 254 897 5550 C 817 559 0403 F 254 897 6652 CP-201100609 Log # TXX-11053 Ref. # 10CFR50.55a April 21, 2011 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555
SUBJECT:
COMANCHE PEAK NUCLEAR POWER PLANT DOCKET NO. 50-446 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION, RELIEF REQUESTS NOS. C-6 AND C-7 (TAC NOS. ME5215 AND ME5216)
REFERENCES:
- 1.
Letter logged TXX-10091 dated December 15, 2010 from Rafael Flores to the NRC submitting Relief Request No. C-6 for the UNIT 1 Second 10 YEAR ISI Interval from 10 CFR 50.55a Inspection Requirements due to Physical Interferences (Second Interval Start Date: August 13, 2000).
- 2.
Letter logged TXX-10092 dated December 15, 2010 from Rafael Flores to the NRC submitting Relief Request No. C-7 for the UNIT 1 Second 10 YEAR ISI Interval from10 CFR 50.55a Inspection Requirements due to Physical Interferences (Second Interval Start Date: August 13, 2000).
- 3.
Email dated April 1, 2011 from Balwant Singal of the NRC to Jack Hicks of Luminant Power requesting additional information regarding Relief Request Nos. C-6 and C-7.
- 4.
Email dated April 5, 2011 from Rob Slough of Luminant Power to Balwant Singal of the NRC.
Dear Sir or Madam:
Per references 1 and 2, Luminant Generation Company LLC (Luminant Power) previously submitted requests for relief from the applicable requirements of Section XI of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, as identified in the referenced relief requests.
Luminant Power has determined that certain inspection requirements of ASME Section XI are impractical due to physical interferences. Per reference 3, the NRC provided a request for additional information regarding the subject relief requests.
Luminant Power has provided the information requested per reference 3 in the Attachment to this letter.
This communication contains no new commitment regarding Comanche Peak Unit 2.
Should you have any questions, please contact Mr. Jack Hicks at (254) 897-6725.
A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway - Comanche Peak.
Diablo Canyon
- Palo Verde San Onofre. South Texas Project
- Wolf Creek
U. S. Nuclear Regulatory Commission TXX-11053 Page 2 of 2 Sincerely, Luminant Generation Company LLC Rafael Flores By: /Fred W. Madden Director, Oversight & Regulatory Affairs
Attachment:
Response to Request for Additional Information c -
E. E. Collins, Region IV B. K. Singal, NRR Resident Inspectors, Comanche Peak Brian Welch, ANII, Comanche Peak Ms. Alice Rogers Environmental & Consumer Safety Section Texas Department of State Health Services 1100 West 49th Street Austin, Texas 78756-3189
Attachment to TXX-11053 Page 1 of 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION FOR RELIEF REQUEST NOS. C-6 and C-7 FOR THE UNIT 1 SECOND 10 YEAR IS1 INTERVAL FROM 10 CFR 50.55a INSPECTION REQUIREMENTS DUE TO PHYSICAL INTERFERENCES (SECOND INTERVAL START DATE: AUGUST 13, 2000) (TAC NOS. ME5215 and ME5216)
The following questions were provided to Luminant Power in the email dated April 1, 2011 from Balwant Singal of the NRC to Jack Hicks of Luminant Power (reference 3) requesting additional information regarding Relief Request Nos. C-6 and C-7:
Generic Question Pertaining to RRs C-6 and C-7
- 1. Please confirm that all examinations included in RRs C-6 and C-7 resulted in no indications, recordable or otherwise. If indications were found, please provide a full description of each indication.
RRC-7
- 2.
Based on the precedent referenced in RR C-7 (Letter No. TXX-98170, dated July 22, 1998, RR C-9), weld TBX-2-1180-2-2 received a coverage of 73% for the First ISI Interval examination.
Does RR C-7 apply to the same weld discussed in the RR C-9 (weld TBX-2-1180-2-2)? If so, please explain why the coverage for this inspection cycle was 41.47% as compared to the prior 73% coverage?
Luminant Power provided the following responses in the email dated April 5, 2011 from Rob Slough of Luminant Power to Balwant Singal of the NRC (reference 4):
Luminant Power's Response to Question 1:
- 1. There were no recordable indications for the UT examinations, identified in Relief Requests C-6 and C-7. The data sheets for the UT examinations, included with Relief Requests C-6 and C-7, clearly state "No" under the 'Recordable Indications" column.
Luminant Power's Response to Question 2:
- 2.
Weld TBX-2-1180-2-2 is the same weld for the heat exchanger, identified in Relief Request C-9 for the first interval of Unit 1 and C-7 for the second interval for Unit 1. The difference in coverage from 73% in the first interval to 41.47% in the second interval was a result of a determination by the Examiner (C. Lasoya) for the second interval that scanning on the weld was not possible because of the contour of the weld crown. Any time the coverage obtained is not > 90% of the required volume, a request for relief is required to be submitted.
During a telephone conversation on April 6, 2011 between Balwant Singal and Rob Slough, further clarification of Luminant Power's response to Question 2 concerning Relief Request C-7 was requested by the NRC. Luminant Power provided the following additional clarification in an email dated April 7, 2011 from Rob Slough of Luminant Power to Balwant Singal of the NRC:
The difference between the estimated examination coverage of weld TBX-2-1180-2-2 from 73% in the First Interval examination to 41.41% for the Second Interval examination can be attributed to the implementation of new EPRI guidelines regarding the acceptability of scanning surfaces.
At the time of the First Interval examination no guideline existed. By the time of the Second Interval examination EPRI had developed guidance for the examination of dissimilar metal
Attachment to TMX-11053 Page 2 of 2 welds. The current industry practice is to apply this description of adequate surface condition to all welds.
A summary of the guidance is as follows: The weld crown condition should be flush with the base material to allow for adequate scanning on top of the weld and butter material. Flush is defined as no more than a 1/32" gap between the search unit and the examination surface for the entire length of the scan.
The subject weld is in an as-welded condition. The scanning on the weld was performed for both the First and Second Interval examinations. The First Interval examiner assumed coverage for the scanning on the weld crown while the Second Interval examiner used the more conservative approach of excluding the scanning performed on the weld crown in calculation of examination coverage.