ML21012A084
| ML21012A084 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 01/26/2021 |
| From: | Kimberly Green Plant Licensing Branch II |
| To: | Jim Barstow Tennessee Valley Authority |
| Green K | |
| References | |
| EPID L-2020-LLA-0114 | |
| Download: ML21012A084 (7) | |
Text
January 26, 2021 Mr. James Barstow Vice President, Nuclear Regulatory Affairs and Support Services Tennessee Valley Authority 1101 Market Street, LP 4A-C Chattanooga, TN 37402-2801
SUBJECT:
WATTS BAR NUCLEAR PLANT, UNITS 1 AND 2 - REGULATORY AUDIT
SUMMARY
RELATED TO REQUEST TO TECHNICAL SPECIFICATION 3.7.11, CONTROL ROOM EMERGENCY AIR TEMPERATURE CONTROL SYSTEM (CREATCS) (EPID L-2020-LLA-0114)
Dear Mr. Barstow:
By letter to the U.S. Nuclear Regulatory Commission (NRC) dated May 19, 2020, Tennessee Valley Authority (TVA) submitted a license amendment request that would revise Watts Bar Technical Specification (TS) 3.7.11, Control Room Emergency Air Temperature Control System (CREATCS), to add a one-time change with a footnote to the Completion Time for Required Action A.1. This footnote allows each CREATCS train to be inoperable for up to 60 days while performing modifications to each respective trains obsolete chiller. The proposed amendments would also add a footnote to the Completion Time for Required Action E.1. The footnote allows an up-to-four-day delayed entry into TS Limiting Condition for Operation (LCO) 3.0.3.
To enhance the review of TVAs request, the NRC staff conducted an audit of supporting documents from September 2 through October 1, 2020. The staff audited the requested documents to confirm certain information relied upon in the license amendment request. A summary of the regulatory audit is enclosed.
J. Barstow The NRC staff did not identify any significant issues during the audit. However, the staff did identify the need for additional information related to the topic of the audit. Separate correspondence containing a request for additional information was transmitted to Mr. Russ Wells on November 17, 2020.
Sincerely,
/RA/
Kimberly J. Green, Senior Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-390 and 50-391
Enclosure:
Regulatory Audit Summary cc: Listserv
REGULATORY AUDIT
SUMMARY
LICENSE AMENDMENT REQUEST TO REVISE TECHNICAL SPECIFICATION 3.7.11, CONTROL ROOM EMERGENCY AIR TEMPERATURE CONTROL SYSTEM (CREATCS)
TENNESSEE VALLEY AUTHORITY WATTS BAR NUCLEAR PLANT UNITS 1 AND 2 DOCKET NOS. 50-390 AND 50-391
1.0 BACKGROUND
A regulatory audit is a planned license or regulation-related activity that includes the examination and evaluation of docketed and non-docketed information. The audit was conducted with the intent to gain understanding, to verify information, and to identify information that will require docketing to support the basis of a licensing or regulatory decision.
By application dated May 19, 2020, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20140A342) Tennessee Valley Authority (TVA, the licensee) submitted a license amendment request (LAR) to Facility Operating License Nos. NPF-90 and NPF-96 for the Watts Bar Nuclear Plant (Watts Bar), Units 1 and 2, respectively. The proposed amendment would revise Watts Bar Technical Specification (TS) 3.7.11, Control Room Emergency Air Temperature Control System (CREATCS), to add a one-time change with a footnote to the Completion Time for Required Action A.1. This footnote allows each CREATCS train to be inoperable for up to 60 days while performing modifications to each respective trains obsolete chiller.
The proposed amendment also adds a footnote to the Completion Time for Required Action E.1.
The footnote allows an up-to-four-day delayed entry into TS Limiting Condition for Operation (LCO) 3.0.3. During the post-replacement testing of each new chiller, both CREATCS trains will need to be declared inoperable to allow for comprehensive testing of the new CREATCS chiller.
As proposed by TVA, both TS changes (i.e., the footnotes) to Action A.1 and Action E.1 are limited to the time that the CREATCS modifications are being performed between the timeframe of May 1, 2021, to October 1, 2022. The applicability of each footnote will expire on October 1, 2022.
The U.S. Nuclear Regulatory Commission (NRC) staff performed a preliminary review of the LAR and determined that a regulatory audit would assist in the timely completion of the review.
The regulatory audit was performed consistent with the NRC Office of Nuclear Reactor Enclosure
Regulation Office Instruction LIC-111, Regulatory Audits, Revision 1, dated October 31, 2019 (ADAMS Accession No. ML19226A274). The NRC staff conducted a regulatory audit that consisted of a remote audit, including discussions with the licensee, from September 2 through October 1, 2020. The audit plan was provided to TVA on August 25, 2020 (ADAMS Accession No. ML20239A969). The list of documents uploaded by the licensee in response to the NRC staffs request and examined by the audit team is provided in Section 5.0.
The NRC staff reviewed documents and held discussions with members of TVA during the week of October 1, 2020, regarding the LAR under staff review. The collective results of the regulatory audit were used by the NRC staff to finalize requests for additional information (RAIs), which was issued on November 17, 2020 (ADAMS Accession No. ML20322A441).
2.0 AUDIT ACTIVITIES AND OBSERVATIONS The remote audit was conducted using an online portal and teleconferencing capabilities. The purpose of the audit was to (1) gain a better understanding of the information in the LARs to support the staffs review, and (2) identify any information that would be required from the licensee to be provided on the docket for the NRC staff to render a staff finding to support the safety evaluation.
The NRC staff made the following observations based on its audit of the documents listed in Section 5.0 of this report:
Supply and return hoses routed through the Service Building and into the Control Building will be used to route the chilled water from the temporary-chilled-water-skid package to the air-handling units (AHUs) in the Control Building. The hoses will be routed as appropriate to the TS inoperable but functional AHU. A manual isolation valve connected to a pipe is integrated into each of two-floor penetrations. The two penetrations are part of the floor of the mechanical equipment room of the Main Control Room Habitability Zone (MCRHZ) on Control Building Elevation 755.0. The two isolation valves with connected pipes will be used for routing the chilled water supply and return hoses to the appropriate MCR AHU located in the mechanical equipment room. Connection to the AHU coils will be made by isolating the plant chilled water piping, removing the flex hoses between the AHU coils and the permanent plant chilled water piping, and then connecting the temporary chilled water supply and return hoses to the AHU coils using the existing flange connections. As noted, the mechanical equipment room is part of the MCRHS area (a.k.a, MCRHZ), which includes all rooms on plan Elevation 755 of the Control Building. The required combined area to accommodate these two breaches, can be procedurally controlled within the constraints of the licensing basis analysis pertaining to design basis accident consequences to control room envelope occupants.
Provisions exist in the Watts Bar temporary modification (i.e., T-mod) work packages to control the spraying effects of leakage in the event either the supply or return hoses develop a leak during the time the temporary chiller is supply cooling water to the inoperable but functional AHU.
The 150-ton (minimum) capacity of the temporary chiller skid exceeds the individual design capacity of each CREATCS AHU.
The temporary chiller skid diesel generator (DG) fuel oil tanks capacity provides a 12-hour run time for the chiller skid without fuel oil replenishment, which allows the licensee time for replenishing measures.
The temporary chiller package will be stationed in the yard, and the chilled water lines run from the chiller package to the inoperable but functional affected AHU. This chiller package will be located at either of the two locations. The two potential locations with respect to assumed plant north are (a) due west of the Auxiliary Building or (b) northwest of the Unit 1 Containment. Both locations will locate the temporary chiller skid approximately 250 feet from both the Auxiliary Building Fresh Air intake and the closest of the two MCR Fresh Air intakes. Final connection of the chilled water lines to the AHU will occur when each to be replaced respective chiller train is taken out of service. In the event that non-safety related 480 volt alternating current (AC) source is lost and the skids DG is required to operate to power the temporary chiller, the staff determined that based on the distance of the skid from the fresh air intakes that any diesel engine exhaust fumes emitted from the skid would be sufficiently dilute so as not to provide a threat to MCR habitability or Auxiliary Building accessibility.
The NRC staff examined WBN-0-2019-031-001, Revision 0, Temporary Chiller to Support Replacement of A-Train MCR Chiller, to confirm that the design and the qualification of the temporary hoses, pipe, fittings, and the valves at the penetrations will minimize the potential for failure of the temporary chiller system and the control room envelope boundary. However, the staff was unable to verify that the temporary hoses, pipe, and fittings are qualified for adequate pressure to protect against rupture and pipe whip, and the valves at the penetrations are qualified for seismic retention to maintain the integrity of the control room envelope boundary. Therefore, the staff developed a RAI regarding this matter.
Discussions on various topics were held with the licensee during an audit call on October 1, 2020. The NRC staff assessed the information from the audit to determine whether the information would be needed to support a regulatory finding, and therefore, needed to be submitted for review by the NRC staff.
3.0 RESULTS OF THE AUDIT During the audit, the NRC staff confirmed information that supported statements made in the LAR. However, the staff identified additional information that is needed to support the staffs regulatory findings. Therefore, subsequent to the audits conclusion, an RAI was sent to the licensee on November 17, 2020 (ADAMS Accession No. ML20322A441).
4.0 AUDIT PARTICIPANTS NRC TVA Enercon Kimberly Green Russell Wells Joel Riddle Raul Hernandez-Figueroa Jerry Thompson Adam Edwards Matthew Hamm Ron Rogers Patricia Furio Yueh-Li (Renee) Li Gordon Williams Paul Schoepf David Nold Matt Smith Brian Wittick Stuart Rymer John Prangle John Sterchi 5.0 LIST OF DOCUMENTS AND MATERIALS PROVIDED IN THE ELECTRONIC READING ROOM Document No. Description NPG-SPP-09.5, Temporary Modifications Temporary Configuration Changes Revision 0015, Attachment 6 WBN-0-2019-031-001, Temporary Chiller to Support Replacement of A-Train MCR Revision 0 Chiller WBN-0-2019-031-002, Temporary Chiller to Support Replacement of B-Train MCR Revision 0 Chiller WBN-47W200-4-AC Equipment Plan-El 737.0 & El 729.0 004133670, Revision 19 WBN-2-47W600-2-CC Unit 2 Electrical Instruments and Controls 055277853, Revision 3 WBN-47W930-5-AC Mechanical Heating, Ventilating and Air Conditioning 003886276, Revision 16 WBN-47W930-3-AC Mechanical Heating, Ventilating and Air Conditioning 003969024, Revision 42 Calculation Main Control Room Floor (EL. 755.0) Transient Temperature MDQ00003120090157, Analysis using Gothic' modelling Revision 7 NPG-SPP-05.4, Chemical Traffic Control Revision 0008 Unit 0, 1, & 2 Technical Breaching the Containment Annulus, ABSCE, or MCRHZ Instruction TI-65 Pressure Boundaries MCRHZ - TI-65, Appendix Breach Permit Log WBN-47W200-3, Revision 16 Equipment Plan - El 757.0 & El 755.0 WBN-47W200-2, Revision 12 Equipment Plan - El 772.0 & Above 2020 TomTom Arial Satellite Annotated to depict two potential temporary chiller locations View of WBN with respect to MCR Fresh Air Intakes and Auxiliary Building Fresh Air Intakes
ML21012A084 *by e-mail OFFICE NRR/DORL/LPL2-2/PM* NRR/DORL/LPL2-2/LA* NRR/DSS/SCPB/BC*
NAME KGreen BAbeywickrama BWittick DATE 01/11/2021 01/13/2021 12/15/2020 OFFICE NRR/DEX/EMIB/BC* NRR/DORL/LPL2-2/BC* NRR/DORL/LPL2-2/PM*
NAME ABuford UShoop KGreen DATE 12/04/2020 01/26/2021 01/26/2021