RBG-47830, License Renewal Application Update - Neutron Absorbing Material Monitoring Program

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License Renewal Application Update - Neutron Absorbing Material Monitoring Program
ML18046A044
Person / Time
Site: River Bend Entergy icon.png
Issue date: 02/15/2018
From: Maguire W
Entergy Operations
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
RBG-47830
Download: ML18046A044 (19)
v • d • e


Text

  • Entergy.

~

Entergy Operations, Inc.

River Bend Stilt ion 5485 US Highway 61 N SI Francisville. LA 70775 Tel 225*381*4374 William F. Maguire Site Vice President River Bend Station RBG-47830 February 15, 2018 Attn: Document Control Desk U.S. Nuclear Regulatory Commission 11555 Rockville Pike Rockville , MD 20852-2738

SUBJECT:

License Renewal Application Update - Neutron Absorbing Material Monitoring Program River Bend Station , Unit 1 Docket No. 50-458 License No. NPF-47

References:

1) Entergy Letter: License Renewal Application (RBG -47735 dated May 25, 2017) (ML17153A282)
2) NRC Letter, "Summary of October 12, 2017, Meeting with Entergy Operations, Inc. on its Intent to Change Neutron Absorbers for the River Bend Station , Unit 1 Spent Fuel Pool ," dated November 2, 2017 (ML17303A042)
3) NUREG-1801 , "Generic Aging Lessons Learned (GALL) Report," Revision 2, December 2010 (ML103490041)
4) Nuclear Energy Institute (NEI) 16-03, "Guidance for Monitoring of Fixed Neutron Absorbers in Spent Fuel Pools," Revision 0, May 2017 (ML17263A133).

Dear Sir or Madam :

In Reference 1, Entergy Operations, Inc. (Entergy) submitted an application for renewal of the Operating License for River Bend Station (RBS) for an additional 20 years beyond the current expiration date. The license renewal application (LRA) credited the Boraflex Monitoring Program , described in Section B.1.3, for managing aging of Boraflex during the period of extended operation.

Subsequently, Entergy notified the Nuclear Regulatory Commission (NRC) (Reference 2) of its intent to install NETCO's SNAP-IN neutron inserts in the RBS spent fuel pool (SFP) storage cells and to change the SFP criticality analysis. This change will remove credit for Boraflex and credit the SNAP-IN inserts in the new criticality analysis. Thus , during the period of extended operation , Entergy will no longer use the Boraflex Monitoring Program , but will use the Neutron Absorbing Material Monitoring Program described in Enclosure 1. The Neutron Absorbing Material Monitoring Program will be consistent with the program described

RBG-47830 Page 2 of 3 in NUREG-1801 (Reference 3) ,Section XI.M40 , "Monitoring of Neutron-Absorbing Materials Other than Boraflex," and will follow the industry guidance in NEI 16-03 (Reference 4) .

The commitment to enhance the Boraflex Monitoring Program is being replaced by a commitment to implement the Neutron Absorbing Material Monitoring Program. A new commitment is being made to replace the neutron absorbing material so that the Boraflex material in the spent fuel pool will not be required to perform a neutron absorption function during the period of extended operation . These commitments are described in Enclosure 2.

If you require additional information , please contact Mr. Tim Schenk at (225)-381-4177 or tschenk@entergy.com.

In accordance with 10 CFR 50.91 (b)(1) , Entergy is notifying the State of Louisiana and the State of Texas by transmitting a copy of this letter and attachment to the designated State Official.

I declare under penalty of perjury that the foregoing is true and correct. Executed on February 15, 2018.

Sincerely, WFM/RMC/alc : License Renewal Application Revisions for the Neutron Absorbing Material Monitoring Program- River Bend Station : Commitments - River Bend Station

RBG-47830 Page 3 of 3 cc : (with Enclosure)

U. S. Nuclear Regulatory Commission Attn : Emmanuel Sayoc 11555 Rockville Pike Rockville , MD 20852 cc: (w/o Enclosure)

U. S. Nuclear Regulatory Commission Attn: Lisa Regner 11555 Rockville Pike Rockville, MD 20852 U. S. Nuclear Regulatory Commission Attn: David Drucker 11555 Rockville Pike Rockville , MD 20852 U.S. Nuclear Regulatory Commission Region IV 1600 East Lamar Blvd.

Arlington , TX 76011-4511 NRC Resident Inspector PO Box 1050 St. Francisville, LA 70775 Central Records Clerk Public Utility Commission of Texas 1701 N. Congress Ave .

Austin, TX 78711-3326 Department of Environmental Quality Office of Environmental Compliance Radiological Emergency Planning and Response Section Ji Young Wiley P.O. Box 4312 Baton Rouge , LA 70821-4312 RBFI 0028

Enclosure 1 License Renewal Application Revisions for the Neutron Absorbing Material Monitoring Program

RSG-47830 Page 2 of 14 2.3.3.15 Fuel Pool Cooling and Cleanup

System Description

The purpose of the fuel pool cooling and cleanup system (system code 602, SFC) is to provide heat removal for spent fuel , to maintain the spent fuel covered with water during all storage conditions, and to maintain required water purity under normal conditions. The system serves the fuel building pools (spent fuel storage pool, cask pool , and lower transfer pool) and the containment pools (refueling cavity, separator storage pool , dryer storage pool, and upper transfer pool) .

The fuel pool cooling and cleanup system consists of two separate subsystems: fuel pool cooling and fuel pool purification. The fuel building spent fuel racks (system 054) employ Boraflex, a fixed neutron absorber or poison material for criticality control with the intended function of providing neutron absorption. Entergy has committed to install aluminum boron-carbide neutron absorbing material before the period of extended operation (i.e., prior to February 28. 2025. or the end of the last refueling outage prior to August 29. 2025. whichever is later) . Upon completion of the installation. the Boraflex material in the spent fuel pool will not be credited to perform a neutron absorption function. Boraflex The neutron absorbing material and the spent fuel pool racks are considered to be components in the fuel pool cooling and cleanup system for purposes of aging management review .

RBG-47830 Page 3 of 14 3.3.2.1.15 Fuel Pool Cooling and Cleanup Materials Fuel pool cooling and cleanup system components are constructed of the following materials.

  • Aluminum/boron carbide
  • Bolting Integrity
  • Boraflex Monitoring
  • External Surfaces Monitoring
  • Internal Surfaces in Miscellaneous Piping and Ducting Components
  • Neutron Absorbing Material Monitoring
  • One-Time Inspection
  • Water Chemistry Control - BWR
  • Water Chemistry Control - Closed Treated Water Systems

RSG-47830 Enclosure 1 Page 4 of 14 Table 3.3.1 Summary of Aging Management Programs for the Auxiliary Systems Evaluated in Chapter VII of NUREG-1801 Table 3.3.1 : Auxiliary Systems Further Item Aging Effect! Aging Management Evaluation Number Component Mechanism Programs Recommended Discussion 3.3.1-51 Boraflex spent fuel Reduction of Chapter XI.M22, "Boraflex No G9AsisteAt witl:! N6J~eG ~ gQ~. +I:!e storage racks: neutron-absorbing Mon itoring" Gl:!aA§e iA ffiatefial ~f9~efties aA9 neutron-absorbing capacity due to fe9l:1Gti9A 9f Ael:ltf9A a9s9f9iA§ sheets (PWR) , spent boraflex Ga~aGit1' 9f tl:!e El9Faflex s~eAt fl:lel fuel storage racks : degradation st9fa§e faGk Ael:ltf9A a9s9F9iA§ sl:!eets neutron-absorbing eX~9seEl t9 tfeateEl ,.\tatef will ge sheets (BWR) ffiaAa§eEl 91' tl:!e Elmaflex M9AitmiA§ exposed to treated Pf9§Faffi .This item was not used.

borated water, Boraflex neutron absorbing sheets will treated water not be credited for neutron absoq;~t i on during the (2eriod of extended o(2eration. Therefore, the Boraflex in the s(2ent fuel storage racks will not (2erform a license renewal intended function .

RBG-47830 Enclosure 1 Page 5 of 14 Table 3.3.1: Auxiliary Systems Further Item Aging Effect! Aging Management Evaluation Number Component Mechanism Programs Recommended Discussion 3.3.1-102 Boral; boron steel , Reduction of Chapter XI.M40, "Monitoring of No +Ris item was R9t ~se9. +Re~e a~e R9 and other materials neutron-absorbing Neutron-Absorbing Materials al~miR~mt99F9R Ga~9ige speRt f~el (excluding Boraflex) capacity; change in other than Boraflex" st9~a~e ~aGk Re~t~9R a9s9~9iR~ sReets spent fuel storage dimensions and loss iR tRe a~xilia~y systems iR tRe SG9pe of racks: neutron- of material due to liGeRse ~eRewal.Consistent with absorbing sheets effects of SFP NUREG-1801. The Neutron Absorbing (PWR) , spent fuel environment Material Monitoring Program will storage racks: manage reduction of neutron-neutron-absorbing absorbing cal2acity, change in sheets (BWR) dimensions, and loss of material of the exposed to treated neutron absorbing materials eXl20sed borated water, to treated water.

treated water

RBG-47830 Page6of14 Table 3.3.2-15 Fuel Pool Cooling and Cleanup System Summary of Aging Management Evaluation Table 3.3.2-15: Fuel Pool Cooling and Cleanup System Aging Effect Aging Intended Requiring Management NUREG-1801 Table 1 Component Type Function Material Environment Management Program Item Item Notes Neutron absorber Neutron Alum inum / Treated water Change in Neutron VII.A2.AP-236 3.3.1-102 A absorl2tion boron (ext) dimensions Absorb ing carbide Material Monitoring Neutron absorber Neutron Alum inum / Treated water Loss of material Neutron VII.A2.AP-236 3.3.1-102 A absorl2tion boron (ext) Absorbing carbide Material Monitoring Neutron absorber Neutron Alum inum / Treated water Reduction in Neutron VII.A2.AP-236 3.3.1-102 A absorl2tion boron (ext) neutron Absorbing carbide absorl2tion Material cal2ac ity Monitoring Neutron absorber J':IJeutron ~ Treated water Change in gorafle* VII.A2.A 87 3.3.1 51 -A-absorption sarbide /. ~ Fflaterial Monitoring elastoFfler properties J':IJeutron absorber J':IJeutron ~ Treated water ~edustion in gorafle* VII.A~.A 87 3.3.1 51 -A-absorption sarbide /. ~ neutron Monitoring elastoFfler absorption sapaGity I

RBG-47830 Page 7 of 14 TABLE OF CONTENTS A.1 AGING MANAGEMENT PROGRAMS 2 A.1.1 Aboveground Metallic Tanks 3 A.1 .2 Bolting Integrity 3 A.1.3 Boraflex MenitoringNeutron Absorbing Material Monitoring 4 A.1.3 Boraflex Neutron Absorbing Material Monitoring The Boraflex Monitering Program manages reduction in neutron absorbing capacity and change in material properties in the Beraflex material affixed to spent fuel racks. A monitoring program for the Boraflex panels in the spent fuel storage racks is implemented to assure that degradatien of the Beraflex material does not compromise the criticality analysis in suppert of the design of spent fuel storage racks. The pregram uses the RACKLI FE predictive cemputer code or equivalent to calculate the gamma dose absorbed by and the amount of boron carbide loss from the Boraflex panels.

The program entails (a) periodic sampling and analysis for silica levels in the spent fuel pool water and trending the results using the RACKLIFE code or equivalent, (b) performing periodic physical measurements of test coupons containing Boraflex material that have been located in the spent fuel pool, and (c) aroal Boron 10 (B 10) density measurement testing of the spent fuel storage racks, such as BADGER [B 10 Areal Density Gage for Evaluating Racks] testing, at a frequency of not less than once every five years. This program assures that the required 5 percent sub criticality margin is maintained.

The Boraflex Monitoring Program will be enhanced as follows.

  • Revise Boraflex Monitoring Program procedures to include aroal B 10 density measurement testing of the spent fuel storage racks, such as BADGER testing , at a frequency of at least once every five years.

The enhancement will be implemented prior to the period of extended operation.

The Neutron Absorbing Material Monitoring Program is a new program that will manage change in material properties, loss of material. and reduction of neutron absorption capacity of the neutron absorbing material in the spent fuel pool. Degradation of the neutron absorbing material that could compromise the criticality analysis will be detected to assure that the required 5% sub-criticality margin is maintained during the period of extended operation. The parameters monitored include the physical condition and dimensions (corrosion , pitting, wear, blisters, bulges) and areal density (neutron absorber loss).

Inspection and test frequencies will be based on plant-specific experience and will be informed by industry operating experience, but will be at least once every 10 years. Test results will be trended and, if necessary, corrective action will be taken to ensure the sub-criticality margin is met.

The program will use monitoring coupons and in-situ inspections and will follow the most current industry guidance, Nuclear Energy Institute (NEil 16-03, "Guidance for Monitoring of Fixed Neutron Absorbers in Spent Fuel Pools," Revision 0, May 2017 (ML17263A133).

This program will be implemented prior to the period of extended operation.

RBG-47830 Page 8 of 14 A.4 LICENSE RENEWAL COMMITMENT LIST Implementation Source No. Program or Activity Commitment Schedule (Letter Number) 3 Boraflex Neutron eARaAGe tRe Boraflex Iml2lement the Neutron Absorbing Prior to February 28, RBG 47735 Absorbing Material Material Monitoring Program as described in LRA Section 2025, or the end of the RBG-47830 Monitoring B.1.3. last refueling outage I2rior to August 29, 2025, whichever is later.

new Neutron Absorbing Install aluminum boron-carbide neutron absorbing Prior to Februa!y 28, RBG*47830 Material Monitoring material before the l2eriod of extended ol2eration so that 2025, or the end of the the Boraflex material in the sl2ent fuel 12001 will not be last refueling outage credited to l2erform a neutron absorl2tion function . I2rior to August 29, Enterg~ shall submit a letter to the NRC, within 60 da~s 2025, whichever is following installation of the new neutron absorbing later.

material, confirming that the Boraflex material is no longer credited for neutron absorl2tion. I

RBG-47830 Page 9 of 14 TABLE OF CONTENTS B.1 AGING MANAGEMENT PROGRAMS AND ACTIVITIES 15 B.1.1 Aboveground Metallic Tanks 15 8.1.2 Bolting Integrity 17 B.1 .3 Boraflex MonitoringNeutron Absorbing Material Monitoring 22 Table B-1 Aging Management Programs Program Section New or Existing B9faflex Neutron Absorbing Material Monitoring B.1.3 existiRlNew

RBG-47830 Page 10 of 14 Table B-2 RBS Aging Management Program Correlation with NUREG-1801 Programs NUREG-1801 Number NUREG-1801 Program RSS Program BeFafle* MeRiteFiR§ [B.~ .dJThis NUREG-XI.M22 Boraflex Monitoring 1801 (;1rogram will not be credited during the

(;1eriod of extended o(;1eration .

+I:lis f3F9§FaFA is Ret iA blse at ~B~.Neutron Monitoring of Neutron-Absorbing XI.M40 Absorbing Material Monitoring Program Materials Other than Boraflex

[B.1.3]

RBG-47830 Page 11 of 14 Table 8-3 R8S Program Consistency with NUREG-1801 NUREG-1801 Comparison Program has Plant- Program has Exceptions to Program Name Specific Enhancements NUREG-1801 199fafle* Neutron Absorbing Material X

Monitoring [B.1 .3]

RBG -47830 Page 12 of 14 B.1.3 BORAFLEX NEUTRON ABSORBING MATERIAL MONITORING Program Description The Boraflex Monitoring Program managos roduction in neutron absorbing capacity and change in material properties in tho Boraflex material affixed to spent fuel racks. A monitoring program for tho Boraflex panels in the spent fuel storage racks is implomented to assure that dogradation of the Boraflex material does not compromise the criticality analysis in support of the design of spent fuel storage racks. The program uses the RACKLIFE predictive computer code or equivalent to calculate the gamma dose absorbed by and the amount of boron carbide loss from the Boraflex panels.

The program entails (a) periodic sampling and analysis for silica levels in the spent fuel pool water and trending the results using the RACKLIFE code or equivalent, (b) performing periodic physical measuroments of test coupons containing Boraflex material that have been located in the spent fuel pool , and (c) aroal B 10 density measurement testing of the spent fuel storage racks, such as BADGER testing , at a frequency of not less than once every five years. This program assuros that the roquirod 5 percent sub criticality margin is maintained.

The Neutron Absorbing Material Monitoring Program is a new program that will manage change in material properties. loss of material. and reduction of neutron absorption capacity of the neutron absorbing material in the spent fuel pool. Degradation of the neutron absorbing material that could compromise the criticality analysis will be detected to assure that the required 5% sub-criticality margin is maintained during the period of extended operation. The parameters monitored include the physical condition and dimensions (corrosion. pitting. wear. blisters. bulges), and areal density (neutron absorber loss).

Inspection and test frequencies will be based on plant-specific experience and will be informed by industry operating experience. but will be at least once every 10 years. Test results will be trended and. if necessary. corrective action will be taken to ensure the sub-criticality margin is met.

The program will use monitoring coupons and in-situ inspections and will follow the industry guidance provided in Nuclear Energy Institute (NEI) 16-03. "Guidance for Monitoring of Fixed Neutron Absorbers in Spent Fuel Pools." Revision O. May 2017 (ML17263A133).

The program will be implemented prior to the period of extended operation.

NUREG-1801 Consistency The Boraflex Monitoring Program , with enhancement, will be consistent with the program described in NUREG 1801 ,Section XI.M22 , Boraflex Monitoring.

The Neutron Absorbing Material Monitoring Program will be consistent with the program described in NUREG-1801.Section XI.M40. Monitoring of Neutron-Absorbing Materials Other than Boraflex.

Exceptions to NUREG-1801 None

RBG-47830 Page 13 of 14 Enhancements The follO'tving enhancement will be implemented prior to the period of extended operation .

ElemeRt Affested ERhaRsemeRt

4. Detection of Aging Effects ~e",ise Qorafle* Monitoring I2rograffi J3rOCe9tlreS to incltlge areal Q ~ g gensity ffieaStlreffient testing of tAe sJ3ent ftlel storage racks, StlCA as QADGE~ testing , at a freqtlency of at least once e..'ery fi",e years.

None Operating Experience The following operating experience provides objective ovidence that the Boraflex Monitoring Program will be effective in ensuring that component intonded functions are maintained consistent \!Jith the current licensing basis during the period of extended operation while Boraflex is credited for neutron absorption in the spent fuel pool.

In 2004, on site testing was performed on a Boraflex coupon from the spent fuel pool with acceptable results.

In 2011, long term Boraflex coupon holder /\4 with coupons 1 3 was removed from the spent fuel pool for on site testing and found acceptable.

In 2011, a condition was identified with a missing reference document listed in the spent fuel pool coupon surveillance program procedure and with how the coupon test evaluation uses the data from measurements of the length and thickness of the coupon. The reference document was found and sent to records. The program procedure 'Has rovised to add acceptance criteria based on tho SFP criticality analysis assumptions of Boraflex length and thickness from EPRI Report NP 6159, "An Assessment of Boraflex Performance in Spent Nuclear Fuel Storage Racks," and a discussion of the basis of the new acceptance criteria was also included.

In 2012, a condition was identified with the criticality safety analysis (GSA) for the spent fuel pool (SFP) and the rate of degradation of Boraflex in the pool. Further analysis determined that the uncertainties associated with the existing information impacted the margin available to credit the Boraflex neutron absorber for long term storage.

Sufficient margin oxisted in the current GSA to bound the Boraflex degradation for more than seven years from the 2015 refueling outage. /\ project was initiated to determine an appropriate action plan to address the SFP Boraflex.

In 2014, long term Boraflex coupon A 5 was removed from the spent fuel pool for on site tosting and found acceptable.

RSG-47830 Page 14 of 14 As discussed in element 10 to NUREG 1801,Section XI,M22, this program considers the technical information and industry operating experience provided in NRC Information Notice (IN) 87 43, IN 93 70, IN 95 38, and NRC GL 96 04 .

The identification of degradation and initiation of corrective action prior to loss of intended function demonstrates that the Boraflex Monitoring Program has been effective. The continued application of proven monitoring methods provides roasonable assurance that the effects of aging 'Nill be managed such that neutron absorbing components 'Nill continue to perform their intended functions consistent with the current licensing basis through the period of extended operation.

The Neutron Absorbing Material Monitoring Program is a new program . Industry operating experience will be considered in the implementation of this program. Plant operating experience will be gained as the program is executed and will be factored into the program via the confirmation and corrective action elements of the RSS 10 CFR 50 Appendix S quality assurance program.

Although the Neutron Absorbing Material Monitoring Program is a new program, RSS has in place basic elements of the program, such as routine inspections performed to industry standards, deficiency identification processes, and corrective actions.

The Neutron Absorbing Material Monitoring Program will be consistent with the program described in NUREG-1801 and in NEI 16-03, both of which are based on industry operating experience that demonstrates that this program is effective for managing the aging effects requiring management. The use of proven program activities provides reasonable assurance that the effects of aging will be managed such that components will continue to perform their intended functions consistent with the current licensing basis through the period of extended operation.

The process for review of future plant-specific and industry operating experience for aging management programs is discussed in Section 8.0.4.

Conclusion The Boraflex Neutron Absorbing Material Monitoring Program provides reasonable assurance that effects of aging will be managed such that applicable components will continue to perform their intended functions consistent with the current licensing basis through the period of extended operation.

Enclosure 2 License Renewal Application Revisions for the Neutron Absorbing Material Monitoring Program Commitments

RBG-47830 Page 1 of 1 This table identifies actions discussed in this letter (Section A.4) that Entergy commits to perform. Any other actions discussed in this submittal are described for the NRC's information and are not commitments .

TYPE SCHEDULED (Check one)

COMMITMENT COMPLETION DATE ONE-TIME CONTINUING (If Required)

ACTION COMPLIANCE Prior to February 28, 2025, or the end of Enhance the Boraflex Implement the Neutron the last refueling Absorbing Material Monitoring Program as X outage prior to described in LRA Section B.1.3.

August 29,2025, whichever is later.

Entergy shall install aluminum boron-carbide neutron absorbing material before the period of extended operation (i.e., prior to February 28, 2025, or the end of the last refueling outage Prior to February 28, prior to August 29, 2025, whichever is later), so 2025, or the end of that the Boraflex material in the spent fuel pool the last refueling X

will not be reguired to perform a neutron outage prior to absorption function. Entergy shall submit a August 29,2025, letter to the NRC, within 60 days following whichever is later.

installation of the new neutron absorbing material, confirming that the Boraflex material is no longer credited for neutron absorption

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