2CAN091702, Proposed Revision to Reactor Vessel Surveillance Capsule Withdrawal Schedule
| ML17257A121 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 09/14/2017 |
| From: | Pyle S Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 2CAN091702 | |
| Download: ML17257A121 (9) | |
Text
Entergy Operations, Inc.
1448 S.R. 333 Russellville, AR 72802 Tel 479-858-4704 Stephenie L. Pyle Manager, Regulatory Assurance Arkansas Nuclear One 2CAN091702 September 14, 2017 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
SUBJECT:
Proposed Revision to Reactor Vessel Surveillance Capsule Withdrawal Schedule Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No. NPF-6
Dear Sir or Madam:
The Arkansas Nuclear One, Unit 2 (ANO-2) Safety Analysis Report (SAR) Table 5.2-12 provides the ANO-2 reactor vessel surveillance capsule removal schedule. There are two notes associated with this table. The first states that Prior to changing removal intervals, NRC approval is required per 10 CFR 50, Appendix H. The second note states Upon issuance of the renewed license, the ANO-2 specimen capsule withdrawal schedule will be revised to withdraw and test a standby capsule to cover the peak fluence expected through the end of the period of extended operation.
In addition, Section 2.G of the ANO-2 Renewed Operating License provides the following condition related to Reactor Vessel Material Surveillance Capsules:
All capsules in the reactor vessel that are removed and tested must meet the test procedures and reporting requirements of ASTM E 185-82 to the extent practicable for the configuration of the specimens in the capsule. Any changes to the capsule withdrawal schedule, including spare capsules, must be approved by the NRC prior to implementation. All capsules placed in storage must be maintained for future insertion. Any changes to storage requirements must be approved by the NRC.
With this submittal, Entergy Operations, Inc., (Entergy) requests the NRCs approval of a revision to the surveillance capsule withdrawal schedule. This request addresses the above requirements.
Administrative Letter 97-004 allows the NRC to approve a proposed change to the withdrawal schedule without a license amendment if the change conforms with the American Society for Testing and Materials (ASTM) Standard Practice E 185-82. The proposed revision complies with the recommendations of ASTM Standard Practice E 185-82 as discussed in the attachment to the letter.
2CAN091702 Page 2 of 2 The current pressure temperature limits for ANO-2 expire at 32 Effective Full Power Years (EFPY). This corresponds to approximately 40 calendars years. The third reactor vessel specimen capsule was withdrawn in accordance with the schedule and the results of the testing of that capsule have been previously submitted to the NRC (2CAN101602, ML16293A593).
Based on those results, ANO-2 is currently developing a submittal to the NRC for revised pressure temperature limits that would expire at 54 EFPY (approximately 60 calendar years).
The third capsule was the last capsule that had a removal interval listed. The three remaining capsules are listed as STANDBYs. This proposed change to the withdrawal schedule will provide the withdrawal interval for one of these standby capsules to support the extended life of the ANO-2 reactor vessel.
This letter contains no new commitments.
Should you have any questions regarding this submittal, please contact me.
Sincerely, ORIGINAL SIGNED BY STEPHENIE L. PYLE SLP/rwc
Attachment:
Proposed Change to Reactor Vessel Surveillance Capsule Withdrawal Schedule cc: Mr. Kriss Kennedy Regional Administrator U. S. Nuclear Regulatory Commission, Region IV 1600 East Lamar Boulevard Arlington, TX 76011-4511 NRC Senior Resident Inspector Arkansas Nuclear One P.O. Box 310 London, AR 72847 U. S. Nuclear Regulatory Commission Attn: Mr. Thomas Wengert MS O-08B1A One White Flint North 11555 Rockville Pike Rockville, MD 20852
ATTACHMENT TO 2CAN091702 PROPOSED CHANGE TO REACTOR VESSEL SURVEILLANCE CAPSULE WITHDRAWAL SCHEDULE
Attachment to 2CAN091702 Page 1 of 6 Proposed Change to Reactor Vessel Surveillance Capsule Withdrawal Schedule INTRODUCTION The NRC has established requirements and criteria in 10 CFR 50.60 for protecting reactor vessels against fracture. The rule requires the reactor vessel material surveillance program meet the requirements set forth in Appendix H to 10 CFR 50, Reactor Vessel Material Surveillance Program Requirements.
Appendix H to 10 CFR 50 provides the NRC staffs criteria for the design and implementation of the reactor vessel material surveillance programs for operating reactors. The rule, in part, requires reactor vessel surveillance program designs and withdrawal schedules to meet the requirements of the edition of American Society of Testing and Materials (ASTM) Standard Practice E185, Standard Practice for Conducting Surveillance Tests for Light-Water Cooled Nuclear Power Reactor Vessels, which is current on the issue date of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code to which the reactor vessel was purchased, although later editions of ASTM E185 may be used inclusive of the 1982 Edition of ASTM E185 (ASTM E185-82). This rule also requires proposed reactor vessel surveillance programs to be submitted to the NRC and approved prior to implementation.
On September 30, 1997, the NRC issued Administrative Letter (AL)97-004 (ML031210296) to all holders of operating licenses for domestic nuclear power plants. In this AL, the NRC staff summarized the Commissions decision promulgated in Commission Memorandum and Order CLI-96-13. In this Memorandum and Order, the Commission found that, while 10 CFR 50, Appendix H, III.B.3, requires prior NRC approval for all withdrawal schedule changes, only certain changes require the NRC staff to review and approve the changes through the NRCs license amendment process (10 CFR 50.90 process). Specifically, only those changes that are not in conformance with the ASTM standard referenced in 10 CFR 50, Appendix H, are required to be approved through the license amendment process, whereas changes that are determined to conform to the ASTM standard only require the staff to document its review and verification of such conformance.
Entergy Operations, Inc. (Entergy) relocated the Arkansas Nuclear One, Unit 2 (ANO-2) surveillance capsule withdrawal schedule from the ANO-2 Technical Specifications (TSs) to the ANO-2 Safety Analysis Report (SAR) consistent with the provisions of Generic Letter 91-01.
The removal of the withdrawal schedule from the TSs did not result in the loss of any regulatory control because changes to the schedule are controlled by the requirements of 10 CFR 50, Appendix H.
When ANO-2 submitted the proposed change to remove the withdrawal schedule from the TS, a change to the schedule was also proposed. The proposed change was to withdraw the third surveillance capsule several years earlier than originally scheduled. This was due to a significant power uprate. In the Safety Evaluation for Amendment 213 of the ANO-2 TSs (2CNA040002, ML003701437), the NRC concluded that the schedule change was in accordance with ASTM E 185-82.
Attachment to 2CAN091702 Page 2 of 6 The ANO-2 SAR, Table 5.2-12, provides the ANO-2 reactor vessel surveillance capsule removal schedule. There are two notes associated with this table. The first states that Prior to changing removal intervals, NRC approval is required per 10 CFR 50, Appendix H. The second note states Upon issuance of the renewed license, the ANO-2 specimen capsule withdrawal schedule will be revised to withdraw and test a standby capsule to cover the peak fluence expected through the end of the period of extended operation.
Also, Section 2.G of the ANO-2 Renewed Operating License provides the following condition related to Reactor Vessel Material Surveillance Capsules:
All capsules in the reactor vessel that are removed and tested must meet the test procedures and reporting requirements of ASTM E 185-82 to the extent practicable for the configuration of the specimens in the capsule. Any changes to the capsule withdrawal schedule, including spare capsules, must be approved by the NRC prior to implementation. All capsules placed in storage must be maintained for future insertion. Any changes to storage requirements must be approved by the NRC.
Section 7.6 of ASTM E 185-82 provides the requirements for the number of surveillance capsules and withdrawal schedule. The standard requires a sufficient number of surveillance capsules be provided to monitor the effects of neutron irradiation on the reactor vessel throughout its operating lifetime and a withdrawal schedule to meet the monitoring requirements. It should be noted that the recommended withdrawal schedule assumed design life of the vessel to be 40 Effective Full Power Years (EFPY). In accordance with Table 1 of the standard, the ANO-2 program was developed using the column for 3 specimen capsules and the associated schedule.
PROPOSED CHANGES TO SCHEDULE Entergy is proposing to make two changes to the capsule removal schedule. The first is considered to be an editorial change. The Removal Interval for capsule number 4 (W-284) is changed from 30 EFPY to the measured interval determined in the capsule summary report (29.94 EFPY).
The second proposed revision to the schedule is to change the interval for capsule number 6 (W-277) from STANDBY to a minimum of 40.00 EFPY. This is based on a 60-year operating life (equivalent to approximately 54 EFPY).
The current capsule removal schedule is shown in Table 1, while Table 2 provides a revised capsule removal schedule that incorporates the proposed changes. Note that the only remaining capsules are listed as STANDBY capsules.
The proposed change will revise the capsule in vessel location 277 (capsule number 6) from a STANDBY to the next capsule that will be withdrawn.
Attachment to 2CAN091702 Page 3 of 6 TECHNICAL ANALYSIS Section 5.2.2, Reactor Vessel Materials Surveillance Program, of the original Safety Evaluation Report for ANO-2 (NUREG-0308, November 1977, ML102850078), states the ANO-2 materials surveillance program will meet the requirements of ASTM E 185-73 except that the beltline specimen material was chosen at random from the six beltline plates rather than in accordance with ASTM E 185-73. This exception does not impact the capsule withdrawal schedule. The NRC concluded that the surveillance program meets the requirements of Appendix H to 10 CFR 50 to the maximum extent practical for a vessel ordered prior to the publication of Appendix H and is, therefore, acceptable.
ASTM E 185-73 requires three surveillance capsules with a fourth and fifth capsule listed as STANDBY. ANO-2 was constructed with six surveillance capsules, three as part of the program and three as STANDBY.
To date, ANO-2 has removed the three surveillance capsules, Capsules W-97, W-104 and W-284. The test results for the plates and welds in the capsules were submitted to the NRC in the following topical reports:
- Capsule W97 data reported in a Battelle Topical Report 2CAN028503 (February 8, 1985)
(8502270518)
- Capsule W104 data report in Babcock and Wilcox Topical Report BAW-2399, Analysis of Capsule W-104, Entergy Operations, Inc., Arkansas Nuclear One Unit 2 Power Plant (September 2001) (ML013090076)
- Capsule W284 data report in Westinghouse Topical Report WCAP-18166-NP, Revision 0, Analysis of Capsule 284 from the Entergy Operations, Inc. Arkansas Nuclear One, Unit 2 Reactor Vessel Radiation Surveillance Program, (October 2016)
The results of the last data report are currently being used to develop revised ANO-2 Technical Specification 3.4.9 Pressure / Temperature limits.
The proposed revision to the surveillance capsule withdrawal schedule is to ensure that the remaining capsules accumulate sufficient fluence to meet the requirements of ASTM E 185-82.
ANO-2 is currently licensed to operate for 60 years. ANO-2 will enter the period of extended operation in the summer of 2018. The Generic Aging Lessons Learned Report (NUREG-1801, Revision 2) provides guidance related to the reactor vessel surveillance program for renewed licenses. Section XI.M31, Item 4 states:
The plant-specific or integrated surveillance 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 capsule at an outage in which the capsule receives a neutron fluence of between one and two times the peak reactor vessel wall neutron fluence at the end of the period of extended operation and tests the capsule in accordance with the requirements of ASTM E185-82.
Attachment to 2CAN091702 Page 4 of 6 It is recommended that the program retain additional capsules within the reactor vessel to support additional testing if, for example, the data from the required surveillance capsule turn out to be invalid or in preparation for operation beyond 60 years. If the projected neutron fluence for these additional capsules is expected to be excessive if left in the reactor vessel, the program may propose to withdraw and place one or more untested capsules in storage for future reinsertion and/or testing.
The fluence value determined from Capsule W-284 is less than the predicted fluence value at 60-years for ANO-2. Therefore, with the proposed revised withdrawal schedule, a standby capsule will be withdrawn during the period of extended operation and tested in accordance with the above guidance.
Capsule W-263 contains some Standard Reference Materials in place of ANO-2 specific reactor vessel material. The material in this capsule is consistent with the material that was in Capsule W-104 (the second capsule withdrawn and tested in the ANO-2 surveillance program). The contents in Capsules W-83 and W-277 are identical. Capsule W-277 was arbitrarily chosen from these two options.
It should be noted that none of the three remaining capsules are required to be shuffled or moved to another location within the vessel. The lead factors for the three capsules are the same (i.e., 1.35) and are sufficiently high enough in current locations to provide capsule data at adequate fluence values for operation to at least 80 calendar years.
At 40 EFPY, the fluence on Capsule W-277 will have reached the projected 60-year peak vessel fluence (4.98 E 19 n/cm2).
Both Capsules W-83 and W-263 need to remain in the vessel as STANDBY capsules. Capsule W-83 would provide the next surveillance capsule to be tested in support of any potential second license renewal efforts. Capsule W-263 should continue to be irradiated for any potential future testing.
The second note to the SAR, Table 5.2-12, has been revised to change the 48 EFPY to 60 EFPY, to be consistent with the discussion above. See Table 2 included on the final page of this letter.
CONCLUSIONS Similar requests for changes to a site specific reactor vessel surveillance capsule schedule have been approved by the NRC. Examples of such include:
- Watts Bar Unit 1, dated March 27, 2014 ML14083A247
- Indian Point Unit 3, dated March 4, 2015 ML15061A040
- Sequoyah Unit 1, dated September 4, 2015 ML15244B222 Based on the above discussions it is concluded that the proposed surveillance capsule withdrawal schedule meets the requirements of ASTM E185-82 for an operating period of up to 60 years.
Attachment to 2CAN091702 Page 5 of 6 TABLE 1 CURRENT CAPSULE REMOVAL SCHEDULE (SAR Table 5.2-12)
At the nearest scheduled refueling outage, reactor surveillance capsules shall be removed and surveillance specimens tested in accordance with the following schedule:
Removal Interval Capsule Capsule Capsule Vessel (EFPY)
Number Location Code Identification Location (Withdrawal Time) 1 1 W-83 83° Standby(a) 2 2 W-97 97° 1.69 (actual, EOC 2) 3 3 W-104 104° 15.7 (actual, EOC 14) 4 6 W-284 284° 30 5 4 W-263 263° Standby(a) 6 5 W-277 277° Standby(a)
Prior to changing removal intervals, NRC approval is required per 10 CFR 50, Appendix H, Reactor Vessel Surveillance Specimen Withdrawal Schedules. Withdrawal schedules may be modified to coincide with those refueling outages or plant shutdowns most closely approaching the withdrawal schedule.
(a)
If required, Capsules designated as Standby under Removal Interval, will be repositioned to ensure that peak fluence is obtained prior to 60 years (48 EFPY). Upon issuance of the renewed license, the ANO-2 specimen capsule withdrawal schedule will be revised to withdraw and test a standby capsule to cover the peak fluence expected through the end of the period of extended operation (Reference 2CAN100302, 2CAN010401, and NUREG 1828).
Attachment to 2CAN091702 Page 6 of 6 TABLE 2 PROPOSED REVISION TO CAPSULE REMOVAL SCHEDULE At the nearest scheduled refueling outage, reactor surveillance capsules shall be removed and surveillance specimens tested in accordance with the following schedule:
Removal Interval Capsule Capsule Capsule Vessel (EFPY)
Number Location Code Identification Location (Withdrawal Time) 1 1 W-83 83° Standby(a) 2 2 W-97 97° 1.69 (actual, EOC 2) 3 3 W-104 104° 15.7 (actual, EOC 14) 4 6 W-284 284° 29.24 (actual; EOC 24) 5 4 W-263 263° Standby(a) 6 5 W-277 277° Minimum of 40.00 Prior to changing removal intervals, NRC approval is required per 10 CFR 50, Appendix H, Reactor Vessel Surveillance Specimen Withdrawal Schedules. Withdrawal schedules may be modified to coincide with those refueling outages or plant shutdowns most closely approaching the withdrawal schedule.
(a)
If required, Capsules designated as Standby under Removal Interval, will be repositioned to ensure that peak fluence is obtained prior to 60 years (54 EFPY). Upon issuance of the renewed license, the ANO-2 specimen capsule withdrawal schedule will be revised to withdraw and test a standby capsule to cover the peak fluence expected through the end of the period of extended operation (Reference 2CAN100302, 2CAN010401, and NUREG 1828).