ML102850596
| ML102850596 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 07/22/2010 |
| From: | Office of Nuclear Reactor Regulation |
| To: | Division of License Renewal |
| References | |
| Download: ML102850596 (4) | |
Text
1 DiabloCanyonNPEm Resource From:
Ferrer, Nathaniel Sent:
Thursday, July 22, 2010 11:10 AM To:
Grebel, Terence; Soenen, Philippe R Cc:
DiabloHearingFile Resource
Subject:
Draft RAI Set 18 - Scoping and Screening and AMR RAIs Attachments:
Draft RAI Set 18 Scoping and Screening and AMR RAIs.doc Terry and Philippe, Attached is Draft RAI Set 18 containing draft RAIs, specifically on portions of the scoping and screening and aging management review. Please review the attached draft RAIs and let me know if and when you would like to have a teleconference call. The purpose of the call will be to obtain clarification on the staff's request.
Please let me know if you have any questions.
NathanielFerrer ProjectManager DivisionofLicenseRenewal OfficeofNuclearReactorRegulation U.S.NuclearRegulatoryCommission (301)4151045
Hearing Identifier:
DiabloCanyon_LicenseRenewal_NonPublic Email Number:
1940 Mail Envelope Properties (26E42474DB238C408C94990815A02F090A76E5B21C)
Subject:
Draft RAI Set 18 - Scoping and Screening and AMR RAIs Sent Date:
7/22/2010 11:09:35 AM Received Date:
7/22/2010 11:09:36 AM From:
Ferrer, Nathaniel Created By:
Nathaniel.Ferrer@nrc.gov Recipients:
"DiabloHearingFile Resource" <DiabloHearingFile.Resource@nrc.gov>
Tracking Status: None "Grebel, Terence" <TLG1@PGE.COM>
Tracking Status: None "Soenen, Philippe R" <PNS3@PGE.COM>
Tracking Status: None Post Office:
HQCLSTR01.nrc.gov Files Size Date & Time MESSAGE 590 7/22/2010 11:09:36 AM Draft RAI Set 18 Scoping and Screening and AMR RAIs.doc 53242 Options Priority:
Standard Return Notification:
No Reply Requested:
No Sensitivity:
Normal Expiration Date:
Recipients Received:
Diablo Canyon Nuclear Power Plant, Units 1 and 2 (DCPP)
License Renewal Application (LRA)
Draft Request for Additional Information Set 18 Scoping and Screening/Aging Management Review D-RAI 2.3.3.4-01 On LRA drawings LR-DCPP-14-106714-03 and LR-DCPP-14-107714-03, the applicant depicts the label stuffing box at locations 31-C, 33-C, and 35-C, but the components are not shown.
On the LRA AMR Table 2.3.3-4 for the component cooling water (CCW) system, the stuffing box component is not listed. The staff requests that the applicant justify the exclusion of the stuffing box from LRA Table 2.3.3-4.
D-RAI 2.3.3.6-02 On LRA drawing LR-DCPP-11-107711-05 at location 59-B, the applicant depicts piping from the isolation valve that leads to the gaseous radwaste vent header as not within the scope of license renewal (i.e. not highlighted). However, on the continuation LRA drawing LR-DCPP-106724-03 at location 31-B, the piping is shown as in scope for 10 CFR 54.4(a)(2). The staff requests that the applicant clarify its exclusion of the non-highlighted piping section at the above location on LRA drawing LR-DCPP-11-107711-05.
D-RAI 2.3.3.7-02 In LRA Section 2.3.3.7 the applicant states, The safety-related components which are served by the backup air/nitrogen system include valves for charging/spray capability, steam dump capability, RCS boration sample capability, the RCS power-operated relief valves for overpressure protection, the letdown isolation valves, and fire water containment isolation valves. The applicant continues with, The backup air/nitrogen supply system provides compressed gas to safety-related air operated components that are required to perform an active safety-related function after the loss of the compressed air system.
Letdown isolation valves LCV-459 and LCV-460 are shown in scope of license renewal under 10 CFR 54.4(a)(1) on LRA drawing LR-DCPP-08-106708-03 (at location 32-A). However, the backup nitrogen supply to the valves air operators is depicted as not in scope of license renewal on LRA drawing LR-DCPP-25-106725-31 (at location 311-C). Since the DCPP LRA description for the compressed gas system specifically includes the letdown isolation valves as one of the safety-related components served by backup gas, then the gas components should be included in the scope of the license renewal under 10 CFR 54.4 (a)(1). The staff requests that the applicant justify excluding the backup air to the letdown isolation valves from scope of license renewal.
D-RAI 2.3.3.7-03 The applicant depicts water traps and oil filters in the compress gas system on LRA drawings as not in the scope of license renewal. By the nature of these components, the water traps and oil filters would contain fluid under system pressure. In accordance with the applicants methodology as stated in DCPP LRA Section 2.1.2.2, fluid-filled components in the vicinity of SSCs in scope of license renewal under 10 CFR 54.4(a)(1) should be included in the scope of
license renewal. The staff requests that the applicant justify the exclusion of these components from the scope of license renewal.
D-RAI 3.1.2.2.14-1 SRP-LR Section 3.1.2.2.14 states that wall thinning due to flow accelerated corrosion (FAC) could occur in steel feedwater inlet rings and supports. GALL Report, item IV.D1-26, references NRC IN 91-19, "Steam Generator Feedwater Distribution Piping Damage," for evidence of wall thinning due to flow accelerated corrosion in these steam generator components and recommends that a plant-specific AMP is to be evaluated because existing programs may not be capable of mitigating or detecting wall thinning due to flow-accelerated corrosion. LRA Section 3.1.2.2.14 addresses wall thinning of steam generator steel feedwater inlet rings and supports due to the aging mechanism of FAC.
The applicant states that since NRC IN 91-19 is specific to Combustion Engineering steam generators and because it does not have this design of steam generator, no action is required.
The applicant also states in plant-specific note 2 of LRA Table 3.1.2-4 that this form of degradation has been detected only in certain Combustion Engineering pre-System 80 steam generators and that its replacement steam generators are Westinghouse Model 54. The applicant further states that no operating experience at DCPP or other units with Westinghouse Model 54 steam generators suggests that wall thinning of the feedrings is occurring; therefore it has determined that this condition is not applicable and no further evaluation is required. The staff does not consider IN 91-19 to be limited to Combustion Engineering steam generators; therefore, the applicant should clarify why no action is required for addressing FAC of the feedwater ring. The staff notes that the applicants description of the new steam generator design in the LRA Sections 2.3.1.4 and B2.1.8 does not provide sufficient details about the feedwater inlet ring and supports to judge whether FAC could potentially occur in the new steam generator design.
The applicant states that it will conservatively credit its Water Chemistry Program (B2.1.2) and Steam Generator Tubing Integrity Program (B2.1.8) to manage wall thinning due to flow-accelerated corrosion of the feedwater inlet ring and supports. Moreover, in LRA Table 3.1.2-4, the staff notes that the applicant manages the carbon steel steam generator separators in the same way as the feedwater ring, without providing sufficient explanation. With respect to secondary side steam generator internals, it is not clear to the staff whether all of them are included within the scope of the Steam generator Tube Integrity Program.
- 1. Please justify why FAC will not be a concern for these steam generator parts during the period of extended operation
- 2. Please confirm that all secondary side steam generator internals, especially the feedwater ring and separators, are included within the scope of your Steam Generator Tube Integrity Program.