ML12030A164
| ML12030A164 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 01/30/2012 |
| From: | Daily J License Renewal Projects Branch 1 |
| To: | Rencurrel D South Texas |
| Daily J | |
| References | |
| TAC ME4936, TAC ME4937 ML12030A164 | |
| Download: ML12030A164 (7) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 January 30, 2012 Mr. D. W. Rencurrel Sr. Vice President, Technical Support and Oversight STP Nuclear Operating Company P.O. Box 289 Wadsworth, TX 77483
SUBJECT:
REQUESTS FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE SOUTH TEXAS PROJECT, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION - AGING MANAGEMENT, SET 11 (TAC NOS. ME4936 AND ME4937)
Dear Mr. Rencurrel:
By letter dated October 25, 2010, STP Nuclear Operating Company (STPNOC or the applicant) submitted an application pursuant to Title 10 of the Code of Federal Regulations, Part 54, to renew operating licenses NPF-76 and NPF-80 for South Texas Project, Units 1 and 2, for review by the U.S. Nuclear Regulatory Commission (NRC or the staff). The staff is reviewing the information contained in the license renewal application and has identified, in the enclosure, areas where additional information is needed to complete the review.
These requests for additional information were discussed with Arden Aldridge, and a mutually agreeable date for the response is within 30 days from the date of this letter. If you have any questions, please contact me at 301-415-3873 or bye-mail at john.daily@nrc.gov.
Sincerely, John W. Daily, Senior Project Mager Projects Branch 1 Division of License Renewal Office of Nuclear Reactor Regulation Docket Nos. 50-498 and 50-499
Enclosure:
As stated cc w/encl: Listserv
SOUTH TEXAS PROJECT, UNITS 1 AND 2, REQUEST FOR ADDITIONAL INFORMATION AGING MANAGEMENT, SET 11 (TAC NOS. ME4936 AND ME4937)
Metal Fatigue - South Texas (060)
RAI4.3-1a (follow-up)
Background
In response to RAI 4.3-1 dated November 21, 2011, the applicant clarified that the charging flow step decrease and return to normal transient assumes 24,000 occurrences for the design number of cycles. In addition, the Fatigue Monitoring Program does not specifically count this event because the number of assumed cycles (24,000) is far greater than the number expected over 60 years.
Issue It is not clear to the staff what the expected number of cycles is over 60 years for the charging flow step decrease and return to normal transient.
If this transient was used as an input into a fatigue time-limited aging analysis (TLAA), it is not clear to the staff why this transient does not need to be monitored by the Metal Fatigue of Reactor Coolant Pressure Boundary Program to ensure the analysis remains valid.
Request Clarify the baseline number of events up to the end of 2008 and the 60-year projected cycles for the charging flow step decrease and return to normal transient. Based on the 40-year and 60-year cycles, justify how they support the statement in the response, "the' assumed cycles (24,000) are far greater than the number expected over 60 years."
In lieu of a justification, include the letdown flow 50 percent decrease and return transient as part of the Metal Fatigue of Reactor Coolant Pressure Boundary Program.
RAI 4.3-2a (follow-up)
Background
In response to RAI 4.3-2 dated November 21, 2011, the applicant stated the letdown flow 50 percent decrease and return transient was included in normal and alternate charging line fatigue analyses and is not a normal operating event with the plant at power. The applicant clarified that this transient was included for conservatism and assumed to occur approximately once a week for 40 years. The number experienced will not approach the limit given the conservatism of this assumption; therefore, this transient is not counted in the Metal Fatigue of Reactor Coolant Pressure Boundary Program.
The staff noted that, as part of the response, the applicant provided a table of the transients used in the fatigue analyses to determine the break locations, in which 1200 cycles of the letdown flow 50 percent decrease and return transient were included in the normal and alternate charging line fatigue analyses.
ENCLOSURE
- 2 Issue It is not clear to the staff what the expected number of cycles is over 50 years for the letdown flow 50 percent decrease and return transient.
If this transient was used as an input into a fatigue TLAA, it is not clear to the staff why this transient does not need to be monitored by the Metal Fatigue of Reactor Coolant Pressure Boundary Program to ensure the analysis remains valid.
Request Clarify the baseline number of events up to the end of 2008 and the 50-year projected cycles for the letdown flow 50 percent decrease and return transient. Based on the 40-year and 50-year cycles, justify how it supports the statement in the response that, "the number experienced will not approach the limit given the conservatism of this assumption; therefore, this transient is not counted in the Metal Fatigue of Reactor Coolant Pressure Boundary Program."
In lieu of a justification, include the letdown flow 50 percent decrease and return transient as part of the Metal Fatigue of Reactor Coolant Pressure Boundary Program.
RAI 4.3-5a (follow-up)
Background
In response to RAI 4.3-5 dated November 21, 2011, the applicant stated for the Unit 1 Class 3 Feedwater Control Valves, the cycle limiting value remains at 10,300, as described in LRA Section 4.3.1.12.
The staff noted that LRA Section 4,3,2.12 states the following (emphasis added):
To obtain acceptable fatigue limits the number of loadings and unloadings between 15 and 100 percent power had to be reduced from 13,200 to 10,300, of loading or unloading for Unit 2. This limit does not apply to design of the Unit 1 feedwater control valves.
Issue It appears that the applicant incorrectly referenced LRA Section 4.3.1.12 in its response, as Section 4.3.1.12 does not exist in the LRA. In addition, the applicant's statements in response to RAI 4.3-5 are not consistent with the information provided in LRA Section 4.3.2.12 Request Clarify the reference to LRA Section 4.3.1.12 that was cited in response to RAI 4.3-5.
Clarify the discrepancy between the response to RAI 4.3-5 and the information provided in LRA Section 4.3.2.12 for the limit of the number of loadings and unloadings between 15 and 100 percent power for Unit 1. Confirm that the 10,300 cycle limit for loadings and un loadings between 15 and 100 percent power is applicable to the Unit 1 feedwater control valves. Provide the necessary revisions to the response to RAI4.3-5 and the LRA.
- 3 RAI 4.3-Sa (follow-up)
Background
In response to RAI 4.3-5 dated November 21, 2011, the applicant stated that "the stress pairing that contributes the most to fatigue was analyzed with 13,177 events when only 10 events were required." In addition, the response states that "the Metal Fatigue of Reactor Coolant Pressure Boundary Program will maintain this margin for the original analysis during the period of extended operation by ensuring that the specified 10 events are not exceeded."
Issue It is not clear to the staff what "event" was analyzed for 13,177 cycles and what document (e.g.
design specification, Code or Standard) required only 10 of these events to be analyzed. It is also not clear which transient is being monitored by the Metal Fatigue of Reactor Coolant Pressure Boundary Program for the "specified 10 events."
The staff reviewed LRA Table 4.3-2 and it is not clear which transient is being monitored in the Metal Fatigue of Reactor Coolant Pressure Boundary Program during the period of extended operation to ensure "that the specified 10 events are not exceeded."
Request Clarify the "event" that is being referenced in the response to RAI 4,3-8 that was analyzed for 13, 177 cycles.
Clarify the requirement that specified that only 10 of these "events" had to be analyzed.
Reference any applicable design specification, Code or Standard that provides this "requirement. "
- Clarify the transient that is being managed by the Metal Fatigue of Reactor Coolant Pressure Boundary Program. Confirm that the "program limiting value" for this transient is 10 cycles and is incorporated into the implementing procedures for this program.
RAI for elastomers exposed to lube oil STP RAI 3.3.2.3.2S-1 (079)
Background
In LRA Table 3.3.2-28, the applicant stated that for elastomer flexible hoses exposed to a lubricating oil internal environment there is no aging effect and no AMP is proposed. The AMR line items cite generic note G. The GALL Report does not address elastomeric materials exposed to lubricating oil.
Issue Given that certain elastomers such as natural rubbers and ethylene-propylene-diene are not resistant to lubricating oil, the staff needs to know the material of construction of the flexible hoses to determine if there are no aging effects.
- 4 Request State the materials of construction of the flexible hoses exposed to lubricating oil as listed in LRA Table 3.3.2-28. If the flexible hoses are constructed of a material that is not resistant to lubricating oil, propose an aging management program or state the basis for why no aging management program is necessary.
January 30, 2012 Mr. D. W. Rencurrel Sr. Vice President, Technical Support and Oversight STP Nuclear Operating Company P.O. Box 289 Wadsworth, TX 77483
SUBJECT:
REQUESTS FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE SOUTH TEXAS PROJECT, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION - AGING MANAGEMENT, SET 11 (TAC NOS. ME4936 AND ME4937)
Dear Mr. Rencurrel:
By letter dated October 25, 2010, STP Nuclear Operating Company (STPNOC or the applicant) submitted an application pursuant to Title 10 of the Code of Federal Regulations, Part 54, to renew operating licenses NPF-76 and NPF-80 for South Texas Project, Units 1 and 2, for review by the U.S. Nuclear Regulatory Commission (NRC or the staff). The staff is reviewing the information contained in the license renewal application and has identified, in the enclosure, areas where additional information is needed to complete the review.
These requests for additional information were discussed with Arden Aldridge, and a mutually agreeable date for the response is within 30 days from the date of this letter. If you have any questions, please contact me at 301-415-3873 or bye-mail at john.daily@nrc.gov.
Sincerely, IRA!
John W. Daily, Senior Project Manager Projects Branch 1 Division of License Renewal Office of Nuclear Reactor Regulation Docket Nos. 50-498 and 50-499
Enclosure:
As stated cc w/encl: Listserv DISTRIBUTION:
See next page ADAMS Accession No: ML12030A164 "concurrence via e-mail OFFICE LA: DLR/RPB1" PM: DLR/RPB1 Be: DLR/RPB1 IPM: DLR/RPB1 NAME YEdmonds JDaily DMorey (JDaily for) JDaily DATE 01/26/12 01/30/12 01/30/12 01/30/12 OFFICIAL RECORD COpy
Letter to D. W. Rencurrel from John W. Daily dated January 30, 2012
SUBJECT:
REQUESTS FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE SOUTH TEXAS PROJECT, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION - AGING MANAGEMENT, SET 11 (TAC NOS. ME4936 AND ME4937)
DISTRI BUTION:
E-MAIL:
PUBLIC RidsNrrDlr Resource RidsNrrDlrRpb1 Resource RidsNrrDlrRpb2 Resource RidsNrrDlrRerb Resource RidsNrrDlrRpob Resource RidsNrrDraApla Resource RidsOgcMailCenter JDaily TTran ICouret, OPA BSingal, DORL WWalker, RIV JDixon, RIV BTharakan, RIV WMaier, RIV VDricks, RIV NOKeefe, RIV AVegel, RIV GPick, RIV