ML17317A608
| ML17317A608 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 12/04/2017 |
| From: | Andrew Hon Plant Licensing Branch II |
| To: | James Shea Tennessee Valley Authority |
| Hon A DORL/LPL2-2 301-415-8480 | |
| References | |
| CAC MF9075, EPID L-2016-LLL-0001 | |
| Download: ML17317A608 (5) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C 20555-0001 December 4, 2017 Mr. Joseph W. Shea Vice President, Nuclear Regulatory Affairs And Support Services Tennessee Valley Authority 3R Lookout Place 1101 Market Street Chattanooga, TN 37402-2801
SUBJECT:
SEQUOYAH NUCLEAR PLANT, UNIT 2 - REVISE THE REACTOR PRESSURE VESSEL MATERIAL SURVEILLANCE CAPSULE WITHDRAWAL SCHEDULE (CAC NO. MF9075, EPID L-2016-LLL-0001)
Dear Mr. Shea:
By letter dated December 23, 2016, the Tennessee Valley Authority submitted a request to revise the withdrawal schedule for the reactor vessel material surveillance program for the Sequoyah Nuclear Plant (SON), Unit 2. The submittal requested replacement of the SON, Unit 2 "S" surveillance capsule with the SON, Unit 2 "W" surveillance capsule in the approved withdrawal schedule. Title 1 O of the Code of Federal Regulations (10 CFR) Part 50, Appendix H, "Reactor Vessel Material Surveillance Program Requirements," requires that proposed changes to the withdrawal schedule be approved prior to implementation.
The Nuclear Regulatory Commission staff has reviewed the proposed revision to the SON, Unit 2 reactor pressure vessel material surveillance capsule withdrawal schedule, and concludes that it is acceptable because it is consistent with NUREG-1801, Revision 2 "Generic Aging Lessons Learned (GALL) Report," and the requirements of 1 O CFR, Part 50, Appendix H.
Docket No. 50-328
Enclosure:
Safety Evaluation cc: ListServ Sincerely, 1l---
Andrew Hon, Project Manager Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REQUEST TO REVISE THE SURVEILLANCE CAPSULE WITHDRAWAL SCHEDULE FOR THE REACTOR VESSEL MATERIAL SURVEILLANCE PROGRAM TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT, UNIT 2 DOCKET NO. 50-328
1.0 INTRODUCTION
By letter dated December 23, 2016 (Agencywide Documents Access Management System (ADAMS) Accession No. ML16362A207), the Tennessee Valley Authority submitted a request to revise the surveillance capsule withdrawal schedule for the reactor vessel material surveillance program for the Sequoyah Nuclear Plant (SQN), Unit 2. The submittal requested replacement of the SON, Unit 2 "S" surveillance capsule with the SQN, Unit 2 'W" surveillance capsule in the approved withdrawal schedule. Title 10 of the Code of Federal Regulations (1 O CFR) Part 50, Appendix H, "Reactor Vessel Material Surveillance Program Requirements,"
requires that proposed changes to the withdrawal schedule be approved prior to implementation.
2.0 REGULATORY EVALUATION
Nuclear power plant licensees are required by Appendix H to 10 CFR Part 50 to implement reactor vessel material surveillance programs to "monitor changes in the fracture toughness properties of ferritic materials in the reactor vessel beltline region... which result from exposure of these materials to neutron irradiation and the thermal environment." Plant-specific surveillance programs must be consistent with the requirements of American Society for Testing and Materials (ASTM) Standard Practice E185, "Standard Practice for Conducting Surveillance Tests for Light-Water Cooled Nuclear Power Reactor Vessels."
In the design of a plant-specific surveillance program, a licensee may use the edition of ASTM Standard Practice E185, which was current on the issue date of the American Society of Mechanical Engineers Code to which the reactor vessel was purchased, or later editions through the 1982 edition. The withdrawal schedule in Table 1 of ASTM E185-82 is defined for the original operating period of 40 years (estimated at 32 effective full-power years [EFPY]). For the period of extended operation, NUREG-1801, Revision 2 (Generic Aging Lessons Learned (GALL) Report), states that the Appendix program shall have, "at least one capsule with a projected neutron fluence equal to or exceeding the 60-year peak reactor vessel wall neutron fluence prior to the end of the period of extended operation. The program withdraws one Enclosure neutron f!uence at the end of the period of extended operation and tests the capsule in accordance with the requirements of ASTM E185-82."
Appendix H of 10 CFR Part 50 describes reactor vessel material surveillance program requirements. Paragraph (lll)(B)(3) requires that, "[a] proposed withdrawal schedule must be submitted with a technical justification as specified in 50.4. The proposed schedule must be approved prior to implementation."
3.0 TECHNICAL EVALUATION
By letter dated September 27, 2013 (ADAMS Accession No. ML13240A320), the Nuclear Regulatory Commission (NRG) approved a revised surveillance capsule withdrawal schedule for SON, Unit 2, to support the license renewal of SON, Unit 2 through the end of the period of extended operation.
At the end of cycle (EOG) 19, Capsules "S" and "W" were relocated to higher neutron fluence locations formerly occupied by Capsules "T" and "U," respectively. The new locations are radiologically equivalent for projected neutron fluence estimates. During this process however, the cap of Capsule "S" was found to be damaged. Therefore, Capsule "S" was removed from the reactor vessel and moved to the spent fuel pool for potential re-insertion at a later date.
The withdrawal of Capsule "W" at EOC 27 is scheduled at a projected neutron fluence of 2.78 E19 n/cm2 (E > 1MeV). The maximum neutron fluence at the reactor vessel inner diameter is projected to be 2.57 E19 n/cm2 (E > 1 MeV) at the end of the period of extended operation (60 years). Therefore, the neutron fluence projected for the withdrawal and testing of Capsule "W" at EOC 27 is greater that the peak reactor vessel neutron fluence at 60 years of operation, but does not exceed twice the peak. This is consistent with Aging Management Program (AMP) XI.M31, Reactor Vessel Surveillance, in NUREG-1801, Revision 2. Therefore, the staff finds the replacement of Capsule "W" for Capsule "S" acceptable as shown in the table below.
I Capsule Vessel Location Lead Factor I
Withdrawal Neutron Number Note (d)
Time (EFPY)
Fluence (x 1019 n/cm2, E>1.0 MeV\\
T 40° 3.11 1.0::7-_ (removed) 0.244 u
140° 3.17 2.91 /removed) 0.654 X
220° 3.18 5.36 /removed) 1.16 y
320° 3.15 10.55 (removed) 2.02 s
4° Note (a)
J.__
3.11
_N_o_te_ (a)
N/A V
176° I
0.94 Standby N/A 2.78 Note /bl w
184'Note (c)
I 3.18 EOC 27 z
356° 0.94 Standbv NIA a) Capsule "S" was relocated from the 4-degree location to the 40-degree location at EOC 19. It was removed from the SQN, Unit 2 reactor vessel at EOC 20 and placed in the spent fuel pool.
b) Value taken from letter dated July 3, 2013 (ADAMS Accession No. ML13192A034),
Enclosure Table 3 for SON, Unit 2 EOC 19 relocation.
c) Capsule "W" was relocated from the 184-degree location to the 140-degree location at SQN, Unit 2 EOG 19.
d) Values taken from letter dated July 3, 2013 (ADAMS Accession No. ML13192A034),
Table 4, except as noted.
4.0 c) Capsule 'W" was relocated from the 184-degree location to the 140-degree location at SON, Unit 2 EOG 19.
d) Values taken from letter dated July 3, 2013 (ADAMS Accession No. ML f 3192A034),
Table 4, except as noted.
CONCLUSION The NRC staff has reviewed the proposed revision to the SON, Unit 2 reactor vessel material surveillance capsule withdrawal schedule, and concludes that it is acceptable because it is consistent with Appendix Hand NUREG-1801, Revision 2.
Principal Contributor: C. Fairbanks Date: December 4, 2017
SUBJECT:
SEQUOYAH NUCLEAR PLANT, UNIT 2-REVISE THE REACTOR PRESSURE VESSEL MATERIAL SURVEILLANCE CAPSULE WITHDRAWAL SCHEDULE (GAG NO. MF9075, EPID L-2016-LLL-0001) DATED DECEMBER 4, 2017 DISTRIBUTION:
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