ML20086S468

Suppls Re Status & Schedule of post-restart commitments.Long-term Mods for Sys 36 in Diesel Generator Bldg & Sys 41 in Standby Gas Treatment Bldg Will Be Completed by End of Cycle 6 Outage

ML20086S468
Person / Time
Site:	Browns Ferry
Issue date:	12/24/1991
From:	Zeringue O TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9201030182
Download: ML20086S468 (10)

Text

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A icwssee Voey Asetr Post ONe Bs N Cwu Area ECW December 24, 1991 O J.*iW Zenngue vee mes.m %,acuy opeens U.S. Nuclear Regulatory Commission ATTN: Document Control Desk j Washington, D.C. 20555 i Gentlemen:

l In the Matter of ) Docket No. 50-260 Tennessee Valley Authority )

BROWNS FERRY NUCLEAR PLANT (BFN) - SUPPLEMENT TO THE STATUS AND SCHEDULE FOR COMPLETION OF UNIT 2 POST-RESTART ISSUES

References:

3. TVA letter dated September 20, 1991, "BFN - Status and Schedule for Completion of Unit 2 Post-Restart Issues"

2. NRC letter, dated November 21, 1991, " Browns Ferry Nuclear Plant, Unit 2 - Post-Restart Commitments" This letter supplements Reference 1 concerning the status and schedule of Unit'2 post-restart commitments.

The enclosure contains a status and schedule for post-restart issues discussed in Reference 2. There are no new commitments identified in l this submittal.

TVA has conducted a review of NUREG-1232 and its supplements, associated NRC inspection reports, NRC/TVA correspondence, and TVA's Tracking and Reporting of Open Ite.ns (TROI) database. TVA will continue to notify NRC upon completion of the Unit 2 post-restart commitments within the scope of NUREG-1232 and its supplements or as required by other licensing commitments. BFh's commitments are tracked to completion on TROI. Thia includes the generr. tion of a folder that has conclusive evidence of completion of the commitment. These folders are availabic onsite for NRC review.

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b U.S. Nuclear Regulatory Commission December 24, 1991 If you have any questions, please contact R. R. Baron, at (205) 729-7566; Sincerely,

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- 0.1 . Zeringue Enclosure cc'(Enclosure):

NRC Resident Inspector Browns Ferry Nuclear Plant

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Route 12, Box 637

! Athens,' Alabama 35611 i

Mr.-Thierry M. Ross, Project' Manager l

U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike

-Rockville, Maryland 20852 Mr. B. A. Wilson,-Project Chief U.S. Nuc1 car Regulatory Commission Region II-101 Marietta Street, NW, Suite 2900

-Atlanta, Georgia 30323 l-l'

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. ENCLOSURE SUPPLEMINTAL STATUS AND SCHEDULE FOR POST-RESTART ISSUES The following is the status and schedule for post-restart issues discussed in Reference 2. The. format follows the list of issues contained in Reference 2.

Unless noted otherwise, the section numbers and pages referenceo below are from NUREG-1232, Volume 3, Supplement 2.

A. Impact of New Amplified Response Criteria (Section 2.2.2.2.3 - Page 2-5)

1. Evaluate, and upgrade as needed, the structural steel elements, connections, base plates, and anchorages of drywell steel platforms qualified to the interim criteria against the long-term criteria (Inspection Report [1R] 50-260/89-42).

STATUS: TVA submitted the design criteria by letter, dated June 12, 1991, "BFH - Corrective Action Plan and Design Criteria for Lower Drywell Steel Platforms and Miscellaneous Steel". TVA corumit t ed to evaluate the Unit 2 lower dryvell steel platf orms and modify them, if required, to meet the enclosed design criteria prior to Unit 2 restart from the next refueling outage.

Open. This commitment will be completed by the end of Unit 2, Cycle 6 outage.

2. Evaluate, and upgrade as needed, the structural steel elements, base plates, connections, and anchorages of miscellaneous steel frames qualified to the interim criteria against the long-term design criteria (IR 50-260/89-42).

STATUS: See response to-item A.1. The commitment and schedule apply '

to drywell' and miscellaneous steel.

3. Conduct the long-term modifications for System 'J b in the diesel generator building and System 41 in the standby cas treatment building that were qualitied to the interim criteria (IR 50-260/89-42).

TVA letter, dated Notember 15, 1991, "BFN - Heating, Ventilstion and Air Conditioning (HVAC) Seismic Design Criceria submitted the design criteria for_NRC review and approval. For HVAC ductwork and supports, i the long-term modifications for rystem 36 in the diesel generator building and system 41 _n the standby gaa treatment building that were qualified to the interim criteria vill be evaluated and modified along with other Class I HVAC duct ano uupports.

Open. This commitment will be completed by the end of Unit 2, C1cle 0 outage.

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4. Complete the long-term evaluation of the impact of the new Amplified Response Spectra (ARS) on the Class I HVAC ductwork and supports in the chimney and modify the ductwork as needed (IR 50-260/89-a2).

STATUS: See response to item A.3. The commitment and schedule apply to Class I HVAC ductwork and supports.

5. Finalize the evsluation method documents for the nuclear steam supply system (NSSS) components (IR 50-250/89-39).

STATUS: This item was closed it. TR 89-62.

6. Demonstrate enmpliance of the long-term design criteria with the FSAR requirements (IR 50-260/89-42).

STATUS: This commitment is complete.

As documented in References 1 and 2 below, the staff's review of TVA's seismic design criteria identified some exceptions to either the FSAR requirements or the criteria generally applied in the nuclear indu.stry such as AISC specification, ASMS code, etc. Therefore, the staff took a post-Unit 2 reatart action item to review TVA's HVAC, dryvell steel platform, miscellaneous steel, and conduit selsmic design criteria to 4 determine if they conform vith BFN FSAR requirements.

TVA considers its actions for this post-Unit 2 restart action item complete based on the following:

1) The design criteria for HVAC was submitted by reference 3, "BFN -

Heating, Ventilation and Air Conditioning (HVAC) Seismic Design Criteria." ,

2) TVA's criteria for the seismic qualification of drywell steel platforms and miscellaneous steel was submitted by Reference 4, and

3) As discussed in References 2 and 5, TVA's final program for the seismic qualification of conduits-will be-included in'the resolution of Unresolve Safety Issue (USI) A-46, Verification of Seismic Adequacy _of' Mechanical and Electrical Equipment in

-. Operating Reactors. This criteria is being reviewed generically

and will not require a 11rowns Ferry plant specific review by the staff.

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References:

1) NRC letter, dated July 26, 1988, Interim Operability Criteria for the Seismic Design Program for the Browns  ;

I Ferry Nuclear Plant, Unit 2.

2) NRC letter, dated January 23, 1991, NUREG-1232, Volume 3, Supplement 2, Safety Evaluation Report on Tennessee Valley Authority: Browns F- y Nuclear Plan.

3) TVA letter, dated November 15, 1991, DFN - Heating, Ventilation and Air Conditioning (IIVAC) Seismic Design Criteria.

4) TV/. letter, dated June 12, 1991, Corrective Action Plan and Design Criteria for Lower Drywell Steel Platforma and  ;

Miscellaneous Steel.  !

l 7 5) TVA letter, dated May 6,1991, Program for Resolving l L Conduit and Conduit Supports Issue Prior to the Restart i E

of Unita 1 - and 3.

l B. Instrument Tubing Program (NUREG-1232, Volume 3, Supplement 1, Section 2.2.3.4 -Page 2-33) i U 1 El . Implement third phase-(i.e., complete engineering evaluations of remaining 70. tubing installations).

STATUS;' As previously , abmitted in TVA. letter, dated  !

June 3 3,1989, "BFN - Unit 2 - Seismic Qualification of Inutrument Tubing", Enclosure 1, item 4 committed TVA to evaluate the 70 BFN Scismic Class 1 tubing installations outside the design baseline boundary post restart.

1 Open. This commitment will be completed by the end of  !

' Unit 2, Cycle 6 outage.

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C. Environmental Qualification of Electrical Equipment (NUREG-1232, Volume 3, Section 3.2.2.1 - Page 3-6)

1. Environmental Qualification Regulatory Guide 1.97 instrumentation. ,

STATUS: NRC letter, dated January 18, 1989, "TVA's August 23, 1988 j Response to NRC Safety Evaluation Report on Browns Ferry Compliance to Regulatory Guide 1.97, 'Instrumentacion for Lightwater Cooled Nuclear Power Plants and Environs Conditions During and Following an Accident' (TAC 00462,;00463)," cover letter; the staff found acceptable the TVA commitment to provide environmentally qualified instrumentation by

-Cycle 7 for Unit 2'for the core spray flow, residual heat removal system flow (LPCI mode), Residual Heat Removal Service Water (RHRSW) flow, and emergency ventilation damper position variables. l Open. These items will be completed by the end of Unit 2, Cycle 6 outage.

D. Piece-Part Qualificatiot Program (Section 3.3 - Page 3-3)

1. Evaluate replacement items installed in safety-related applications other~than 10 CPR 50.49 system.

2. Develop pre-engineered specifications detailing technical and quality requirements, source audit and inspection requirements, receipt inspection requirements, part conditioning requirements, and if applicable, post-maintenance testing requirements.

3. Establish a conditional release program that will require

-justification and review by senior management for installation of any item that is nonconforming or otherwise not documented as meeting criteria for a specific safety-related application.

11em No. D.1:

TVA letter, dated September 20, 1991, "BFN - Status and Schedule for Completion of Unit' 2 Post-Restart Issues," was intended to include both installed and inventoried replacement items for safety-related applications other than 10 CFR f^ 49 systems.

Open. The_ inventoried and installed-activities in safety-related applications other than 10 CFR 50.49 systems will be completed by_

September 30, 1993.

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Item._No. D.21

'The' pre-engineering specifications detailing technical and quality ,

requirements, source audit and inspection requirements,_ receipt )

inspection requirements, part conditioning requirements, and if applicable, post-maintenance testing requirements have been completed.

Closed. BFN procedures are in place to maintain this portion of the Piece-Part Qualification Program.

Item No. Dgli A conditional release program that requires justification and review by senior management for installation of any item that is nonconforming or otherwise not documented as meeting criteria for a specific _ safety-relsted application has been completed.

Closed. BFN procedures are in place to maintain this portion of the Piece-Part Qualification Program.

E. Probabilistic Risk' Assessment (Section 3.9 - Page 3-8)

1. Revise BFHP PRA~to reflect short- and long-term ECCS pump combination requirements.

2. Revise human factors considerations and incorporate use of hardened vent in BFNP PRA.

Item No. E.11

-_As previously submitted in TVA letter, dated October 26, 1990, "NUREG-1232 and NUREG-1232, Supplement 1, Safety Evaluation Report",

page 13,.Section 3.9-provided the status on the short- and long-term ECCS pump requirements. .TVA committed to. revise the BFNP PRA to refleet'short- and long-term pump requirements to be completed with the next PRA update. The BFN PRA will be performed in accordance with the requirements of Generic Letter 88-20 as committed in TVA's

__0ctober 30, 1989 letter.

Open. TVA is committed to submit the BFN PRA in accordance with oGL 88-20-by September 1, 1992.

Item No. E.2:

Human Factors:

As previously submitted in TVA letter, dated May 1, 1990, "BFN -

Probabilistic Risk Assessment (PRA) and Emergency Operating Procedure (EOP)," TVA will revise the human factors considerations for the next PRA update.

Open. TVA is committed to provide a summary report of the updated PRA by September 1, 1992.

l Incorporate Use of Harde.D.ed Vent As previously submitted in TVA letter, dated October 30, 1989, "BFN -

Response to Generic Letter (GL) 89-16 ' Installation of Hardened Wetvoll Vent'," TVA committed to install the hardened vent in BFN Unit 2 during the next refueling outage. Also, TVA letter dated May 1, 1990, "BFN Probabilistic Risk Assessment (PRA) and Emergency Operating Procedure (EOP)" stated that when BFN installed the hardened vent, the BFN PRA would be updated to reflect this change in plant i design. If the modification was incorporated prior to completion of the next update of the PRA, it would be incorporated in the update.

If the hardened vent was installed after the current update of the BFN  ;

PRA, the hardened vent would be incorporated into the next update of I the BFN FRA. Currently, the s;hedule for the design of the hardened vent does not support the inclusion of the hardened vent into the September 1, 1992 PRA update.

F. Cable Installation (Section 3.11.5 - Pages 3-17 and 3-19)

1. - Test and trend Group 2 cables.

2. Resolve bend ~ radius and vertical drop concerns for medium voltage cables.

3. Establish environmental qualification of Brand Rex cables.

Item No. F.1:

-As previously submitted in TVA letter, dated September 19, 1990, "BFN Unit 2 - Resolution of Cable Installation Issues Supplement Report Corrective Actions - Cable Pullby", Enclosure 2, paragraph 2.0, states: " Group 2 cables will be tested to the requirements of SMI-65 during the next scheduled Unit 2 outage and subsequent outages to facilitate a trend analysis."

Open. TVA is evaluating the extent of the testing remaining to complete this commitment by the end of Unit 2, Cycle 6.

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Jtem No. F.23 MEDIUM VOLTAGE CABLE BEND RADIUS This commitment is closed based on the program revised and approved by NRC prior to restart. The bend radius issue concerns damage that may result when cables are bent beyond a minimum radius. As a part of the BFN Unit 2 Restart effort, class 1E medium voltage cables required for Unit 2 operation were inspected for cable bend radius using Construction Specification G-38 as acceptance criteria. All nonconformances were noted and ranked according to severity. The supplemental report, transmitted to NRC via letter dated July 10, 1990, and the subsequent-revisions described TVA's program for resolution of the bend radius issue. This program excluded cables being replaced by other programs and diesel generator neutral ground circuits. The worst 15 case cables were Hi-Pot tested at the maintenance levels of IEEE Standard 400-1980, and all passed. The cables were then categorized according_to severity _ levels into three groups. Group 1 cables (most severe) are scheduled for replacement during the next refueling outage. Group 2 cables are to be tested during the BFN Unit 2, Cycle 6 outage and subsequent outages to assess L the need for continued trending. Group 3 cables (least tevere) will be subject to only normal maintenance testing.

Implementation of the cable installation program was reviewed by NRC as documented in Inspection Report 90-13. NRC concluded in IR 90-13 that the cable installation program was being properly implemented.

NRC stated further in IR 90-13 that successful completion of the Hi-Pot test should demonstrate the integrity of the cable installation at BFN.

VERTICAL DROP ISSUE This commitment is closed. TVA letter, dated July 10, 1990, "BFN -

Unit 2 - Cable Installation Issues Supplemental Report Corrective Actions," page 7, paragraph 3.3 provided the disposition of existing vertical support conditions.

I 'Seven Class 1E cables' vere technically justified in TVA G-38 SRN 32 l (B22 890112 002) " Variance Number 5 - 5 kV Vertical Support Violations" to remain installed with unsupported vertical drops greater than recommended by Article 300-19 of the National Electrical Code 1987. The-justification is based on the same method used for the unsupported vertical cable concern identified in the Technical l- Evaluation Report for TVA's_Sequoyah Nuclear Plant. This method calculated static: sidewall bearing pressure values using equations l

recommended by the Kerite Company and the Okonite Company.- The l sidewall pressures are less than the maximum recommended by Kerite and Okonite. One remaining cable (ES2513-II).has been modified to add a support, in accordance with the requirements of General Construction Specification G-38.

Class 1E medium voltage cables required for Unit 2 operation were walked down- for conformar.e to G-38. (See NRC IR 90-13, paragraph 4.7.2.6) Vertical ser,61ons of cabic (except those cables being replaced by other rcograms) with unsupported lengths greater than that allowed by G-38 vt.re Hi-Pot tested at the maintenance voltage levels in-IEEE Standard 400-1980, and found to pass. Following this, static sidewall bearing pressure (SSBP) calculations were performed to determine if they were in the acceptable range. Cable supports were added for those cables not technically justified by this analysis.

Item No. F.3:

As previously submitted in TVA letter, dated January 23, 1991, "BFN -

Unit 2 - Brand Rex Cable", provided closure of'this issue.

Closed. The engineering evaluation concluded that the cables are capable of performing their intended safety function for at least one cycle. TVA-is evaluating the continued use of Brand Rex cable in safety-related application beyond Cycle 6.

G. Microbiological 1y Induced Corrosion (Section 3.14 - Page 3-27)

1. Examine and trend EECW velds for MIC damage.

STATUS: As previously submitted in TVA letter, dated September 29, 1988, "BFN - Units'1, 2 and 3 - Microbiological 1y Induced Corrosion (MIC)-Program," TVA committed to determine the rate that MIC is progressing in-the stainless steel velds of the EECW system. The velds identified with MIC and possible MIC indications in the 1987 inspection effort were re-inspected using RT before Unit 2 restart and will be reinspected at each Unit 2 refuel outage. This effort covers Units 1, 2 and 3 and the common EECW piping. In addition, a population of the Unit 2 butt velds which were previously inspected by RT will be reradiographed at each Unit 2 outage to ensure structural integrity of the system and to establish a trend for MIC' damage.

Open. The next inspection effort will be at the end of Unit 2,.

Cycle 6 outage. This will provide the-r.ata needed to establich the trend analysis and close this item, l