ML11312A176
| ML11312A176 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 12/06/2011 |
| From: | Daily J License Renewal Projects Branch 1 |
| To: | Rencurrel D South Texas |
| Daily J | |
| References | |
| TAC ME4936, TAC ME4937 | |
| Download: ML11312A176 (7) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 December 6,2011 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 9 (TAC NOS. ME4936 AND ME4937)
Dear Mr. Rencurrel:
By letter dated October 25, 2010, STP Nuclear Operating Company 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, Jd;::~~anager 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 9 (TAC NOS. ME4936 AND ME4937)
Bolting Integrity (019)
RAI B2.1.7-3
Background
GAll Report AMP XI.M18, "Bolting Integrity," recommends that high strength structural bolting with greater than 1 inch nominal diameter be volumetrically examined for stress corrosion cracking in addition to the American Society of Mechanical Engineers (ASME) Code required visual examination. The applicant's Bolting Integrity Program Basis Document states that volumetric examinations of high strength structural bolts with greater than 1 inch nominal diameter is not required because the corrosive environment needed for stress corrosion cracking (SCC) to occur has been eliminated by following proper lubrication and sealant guidelines. By letter dated August 15, 2011, the staff issued RAI B2.1. 7 -2 requesting that the applicant provide additional information to demonstrate that all high strength structural bolts have been completely removed from a corrosive environment. In its response dated September 15, 2011, the applicant stated that the high strength structural bolts are located in the reactor containment building, which has an environment of plant indoor air that is not corrosive and that the subject bolts are visually inspected for corrosion in accordance with the ASME Code,Section XI, Subsection IWF.
The corrosive environment needed for SCC of high strength materials to occur, as documented in EPRI NP-5769 and NUREG-1339, is an environment containing moisture or humidity. The staff noted that typical reactor containment building environments are warm and humid, and that localized areas may experience high humidity and condensation. EPRI NP-5769 documents failures of high strength structural bolts for steam generators which were exposed to humidity.
The staff also noted that degradation of sealants and lubricants increases with time and can allow for localized corrosive environments in the crevices of bolted connections. In addition, humidity can affect the threaded portions of bolting and cause corrosion that would not be identified by a visual inspection of the surface.. The staff further noted that the visual inspections performed by the ASME Code,Section XI, Subsection IWF, are not intended to identify corrosion of the bolt threads or to identify SCC.
Issue It is unclear to the staff how a non-corrosive environment is achieved locally for each in-scope high strength structural bolt. It is also unclear to the staff how visual inspection of the exterior surface of the bolting is adequate to detect SCC in the threaded portions of the bolted connections.
Request Provide additional information to demonstrate that all in-scope high-strength structural bolts with greater than 1 inch nominal diameter have been completely removed from a localized corrosive environment and are not at risk of being exposed to a corrosive environment during the period of extended operation, or update the program to include volumetric examinations comparable to that of ASME Code Section XI, Table IWB-2500-1, Examination Category BG-1.
- 2 Aboveground Tanks (030)
RAI B2.1.20-5A (Follow-up)
Background
The response to RAI B2.1.20-5 states:
The auxiliary feedwater storage tank (AFST) penetrations are not caulked. The stainless steel tank liner is completely encased in concrete that was poured around the liner and all tank penetrations (approximately two feet thick). Any gaps or spaces on the tank exterior and around penetrations are grouted to prevent water entry.
The GALL Report AMP XI,M29, "Aboveground Metallic Tanks," "parameters monitoredlinspected" program element states that, "[t]he AMP utilizes periodic plant inspections to monitor degradation of coatings, sealants, and caulking because it is a condition directly related to the potential loss of materials." The "detection of aging effects" program element states that, "[c]onducting periodic visual inspections at each outage to confirm that the paint, coating, sealant, and caulking are intact is an effective method to manage the effects of corrosion on the external surface of the component." The "acceptance criteria" program element states, "[d]rying, cracking, or missing sealant and caulking are unacceptable and need to be evaluated using the corrective action program. The evaluation will determine the need to repair the sealant and caulking."
In addition, Table 3.0-1, Final Safety Analysis Report Supplement for Aging Management of Applicable Systems, "Aboveground Metallic Tanks" program states:
This program includes preventive measures to mitigate corrosion by protecting the external surfaces of steel components, per standard industry practice, with sealant or caulking at the concrete-component interface. Visual inspection during periodic system walkdowns should be sufficient to monitor degradation of the protective paint, coating, cauking, or sealant.
Issue The staff considers that the grout that has been installed to prevent water entry between the stainless steel AFST liner and its concrete enclosure is equivalent to a sealant described in GALL AMP XI,M29. Therefore, the grout should be inspected for cracking to ensure that water is not leaking into the space between the liner and the concrete enclosure. The staff could not find any AMR items that manage this grout. LRA Section B1.20, External Surfaces Monitoring program and the appropriate AMR table should be revised to reflect the inspection of the grout as described in GALL AMP XI,M29.
In addition, given the function of the grout, the Updated Final Safety Analysis Report Supplement should be revised to reflect crediting the grout and its inspection to ensure that these aspects are reflected in the CLB during the period of extended operation.
Request Explain why periodic inspections of the grout are not needed to ensure that the grout is not degrading, or propose an AMP to manage the aging of the grout.
- 3 Water Chemistry (002)
RAI 3.3.2.3.19-2
Background
The GAll Report XI.M2, "Water Chemistry," states that verification of the effectiveness of the chemistry control program is undertaken to ensure that significant degradation is not occurring and the component's intended function is maintained during the period of extended operation.
An acceptable verification program is a one-time inspection of selected components at susceptible locations in the system.
In lRA Table 3.3.2-19, the applicant states that the chemical and volume control system's concentrated boric acid sample cooler will be managed for loss of material by only the Water Chemistry program.
In lRA Tables 3.2.2-3 and 3.3.2-2, the applicant manages reduction of heat transfer in the residual heat removal (RHR) heat exchanger, the RHR pump seal water cooler, and the spent fuel pool cooling and cleanup system's spent fuel pool heat exchanger with the Water Chemistry and the One-Time Inspection program.
Issue The chemical and volume control system's concentrated boric acid sample cooler is only managed by the Water Chemistry program, which is inconsistent with the guidance in the GAll Report and inconsistent with the aging management pattern shown in the lRA for other similar heat exchangers.
Given that heat exchangers can have low flow or stagnant areas, it is prudent to include a verification program with the primary aging management program.
Reguest State the basis for omitting the One-Time Inspection program in conjunction with the Water Chemistry program for the chemical and volume control system's concentrated boric acid sample cooler. This arrangement would verify the effectiveness of the Water Chemistry's aging management for this component consistent with the GAll Report.
Inaccessible Cable (051)
RAI 82.1.25-4
Background
GAll Report AMP XI.E3, program element "Detection of Aging Effects" states, "For power cables exposed to significant moisture, test frequencies are adjusted based on test results (including trending of degradation where applicable) and operating experience."
Issue The applicant in its lRA supplement dated June 16, 2011, and RAI response dated October 10, 2011, revised the basis document associated with AMP XI.E3 (B2.1.25), Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 EQ Requirements program, lRA Appendix B2.1.25 and Table A4-1, Item 20 to include trending of the cable test results based on the type
-4 of test performed. However, the applicant did not indicate whether test frequencies may be increased based on test results or operating experience consistent with the recommendations in GALL AMP XI.E3.
Request Explain why the basis document associated with LRA AMP B2.1.25, Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 EQ Requirements program, LRA Appendix B2.1.25, LRA Appendix A1.25, and Table A4-1, Item 20 does not address adjusting the test frequency based on test results and operating experience.
December 6, 2011 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 9 (TAC NOS. ME4936 AND ME4937)
Dear Mr. Rencurrel:
By letter dated October 25, 2010, STP Nuclear Operating Company 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:
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Letter to D. W. Rencurrel from John W. Daily dated December 6, 2011
SUBJECT:
REQUESTS FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE SOUTH TEXAS PROJECT, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION - AGING MANAGEMENT, SET 9 (TAC NOS. ME4936 AND ME4937)
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