ML23010A254
| ML23010A254 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 01/12/2023 |
| From: | Tennessee Valley Authority |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| EPID L-2022-LRM-0098 | |
| Download: ML23010A254 (1) | |
Text
Watts Bar Nuclear Plant Watts Bar Nuclear Plant (WBN)
Pre-submittal Meeting for Expedited License Amendment Request Main Control Room (MCR) Chiller Completion Time Extension January 12, 2023
Agenda
- Introduction
- Background
- Current Technical Specification (TS) Requirements
- Reason for the Proposed Change
- Revised MCR Chiller Replacement Schedule
- Proposed Technical Specification Changes
- Changes to MCR Temporary Chilled Water Equipment Description
- Schedule Milestones
- Closing Remarks 2
Introduction
- The purpose of this meeting is to discuss a proposed expedited license amendment request (LAR) for WBN Units 1 and 2.
- TVA is requesting an expedited license amendment for a revision to the one-time footnotes to WBN Units 1 and 2 Technical Specification (TS) 3.7.11, Control Room Emergency Air Temperature Control System (CREATCS), Required Actions A.1 and E.1 to reflect a change in the scheduling dates for the CREATCS chillers [main control room chillers (MCR) A and B].
- There are no technical changes or changes to the TS compensatory measures associated with the proposed amendment.
- The proposed change is due to delays in the vendor delivery of the MCR CREATCS chillers, which were beyond the control of TVA.
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Background
- 5/19/2020 - TVA submits the LAR to modify the WBN Units 1 and TS for MCR completion time extension (ML20140A342). LAR includes technical information on the MCR CREATCS replacement project including the temporary chilled water system to be utilized during the MCR CREATCS replacement project.
- 9/2/2020-10/1/2020 - NRC conducts an audit of the LAR (ML21012A084)
- 12/16/2020 - TVA responds to NRC RAI (ML20351A424)
- 5/5/2021 - NRC approves the LAR (ML21078A484) l 4
Current TS Requirements Units 1 and 2 - TS 3.7.11 Footnote for Action A.1 l 5
Current TS Requirements Units 1 and 2 - TS 3.7.11 Footnote for Action E.1 l 6
Reason for the Proposed Change
- Due to unforeseen supplier chain issues, TVA is unable to meet the current TS date range of May 1, 2022, to May 1, 2023, for the MCR chiller replacement as required by the existing footnotes to the Completion Time for WBN Units 1 and 2 TS 3.7.11, Required Actions A.1 and E.1.
- As shown in Table 1, the new MCR chillers have not yet been received and are not scheduled to be installed until the third quarter 2023.
- TVA has received confirmation from the supplier vendor that they can currently meet the delivery dates for the MCR chillers.
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Revised MCR Chiller Replacement Schedule Table 1 Revised WBN MCR Chiller Replacement Timeline Activity Date U1R18 Outage 4/14/2023-5/13/2023 Qualification of MCR Chillers 4/28/2023 New MCR B Chiller at WBN 5/4/2023 New MCR A Chiller at WBN 5/9/2023 Replace existing MCR B chiller 9/4/2023 - 10/12/2023 U2R5 Outage 11/03/2023 - 12/02/2023 Replace existing MCR A chiller 1/29/2024 - 4/29/2024 U1R19 Outage 11/1/2024-12/13/2024 l 8
Proposed TS Changes
- Revise the current start and end dates in the footnotes to TS 3.7.11, Required Actions A.1 and E.1 to September 1, 2023, to December 31, 2024, respectively (provides a margin for any potential further schedule delays).
Reflects the current MCR replacement schedule (allowing for margin for any potential further schedule delays).
Requires expedited NRC review and approval of the LAR because NRC approval would be required no later than August 1, 2023 (allowing 30 days for implementation).
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Proposed Technical Specification Change Units 1 and 2 - TS 3.7.11 Footnote for Action A.1 l 10 PLACE THE TITLE OF THE PRESENTATION HERE
Proposed Technical Specification Change Units 1 and 2 - TS 3.7.11 Footnote for Action E.1 l 11 PLACE THE TITLE OF THE PRESENTATION HERE
Changes to MCR Temporary Chilled Water Equipment Description
- There are no technical changes to the replacement planned MCR CREATCS chillers as described in the previous LAR (ML20140A342) and the NRC safety Evaluation (SE) (ML21078A484).
- Differences between the currently planned MCR temporary chiller equipment description and the MCR temporary chiller equipment description in Section 3.1 to the previous LAR and the NRC Regulatory Audit Summary (ML21012A084) are provided in Tables 2 and 3, respectively. There are no changes to the MCR temporary chiller equipment description in the previous TVA RAI response (ML20351A424).
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Table 2 Item No. Description in LAR Currently Planned Installation Reason for Change Significance 1 Page E6 of 24, paragraph 1 describes, The inlet and outlet piping will To allow more efficient This new configuration The chilled water piping inlet and no longer be removed. (less time) transition is functionally outlet to the AHUs is removed and Permanent branch connections between the temporary equivalent to the replaced with temporary piping for the with isolation valves are being and permanent chillers configuration described temporary chiller system. added via permanent which will be in the LAR and is modification to the inlet and advantageous during expected to benefit the outlet piping to the AHUs to the post modification project by reducing the allow connection of the test (PMT) window and time in the TS Required temporary chiller without should reduce time in Action Completion removal of piping. the TS Required Action Time.
Completion Time.
2 Page E6 of 24, Section 3.2 describes The temporary chiller The temporary chiller These items were major equipment and includes Chilled installation may have as many installation includes included for water Pump. as three pumps. Additionally, multiple pumps to meet completeness of one major equipment item necessary hydraulic information.
that was not included in the conditions. The LAR description is a transfer temporary chiller switch, to allow transfer installation includes a between plant power and the transfer switch.
diesel generator (DG) for the temporary chiller.
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Table 2 Item No. Description in LAR Currently Planned Installation Reason for Change Significance 3 Page E6 of 24, Section 3.2.1 The DG referred to in the LAR (a Clarification on the Both the rented refers to a 320kW DG. Section rented Aggreko chiller) is rated at rating of the Aggreko Aggreko equipment 3.2.4 also refers to the 320kW 320kW at 50Hz. The rating of this DG and to include and the Carrier/CAT DG. DG is 300kW at 60Hz, which is reference to the CAT equipment have adequate for the temporary/rented generator which the adequate electrical and Aggreko chiller equipment. A site has purchased, cooling capacity to Caterpillar (CAT) generator and along with a Carrier meet the requirements Carrier chiller have also been chiller. for the temporary chiller purchased by the site to reduce system.
reliance on rented equipment. The ratings (tons and kW) of the CAT/Carrier equipment exceed the ratings of the rented Aggreko equipment.
4 Page E6 of 24, Section 3.2.1, Permanent branch connections have To allow more efficient This new configuration second paragraph states, been added to the AHU piping, (less time) transition is functionally Connection to the AHU coils will Therefore, it is more accurate to state between the temporary equivalent to the be made by isolating the chilled "Connection to the AHU coils is made and permanent chillers configuration described water piping, removing the flex via permanent flanged branch which will be in the LAR and is hoses between the AHU coils connections with an isolation valve, advantageous during expected to benefit the and the chilled water piping and which were added as part of the the PMT window and project by reducing the then reconnecting the temporary chiller replacement project should reduce time in time in the TS Required chilled water supply and return subsequent to the submittal of the the TS Required Action Action Completion hoses to the AHU coils using LAR." Completion Time. Time.
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Table 2 Item No. Description in LAR Currently Planned Installation Reason for Change Significance 5 Page E7 of 24, Section 3.2.2 Hose sizes used in the temporary Final configuration to Larger hose sizes meet refers to 2.5 inch() diameter chilled water system are of various meet hydraulic hydraulic requirements supply and return hoses. sizes (3, 4 and 6) requirements. and offer less resistance compared to smaller hose sizes.
6 Page E7 of 24, Section 3.2.3 As noted in the NRC audit summary, Provide flexibility in Both locations are a states, The equipment "The two potential locations with chiller locations. similar distance (hose associated with the temporary respect to assumed plant north are run). Both locations chiller system will be located in (a) due west of the Auxiliary Building are also sufficiently the yard west of the Auxiliary or (b) northwest of the Unit 1 distant from the plant Building and in the Control Containment." air intakes.
Building (Elevation 729.0 feet).
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Table 2 Item No. Description in LAR Currently Planned Installation Reason for Change Significance 7 Page E7 of 24, Section 3.2.3 This statement is intended to mean Clarification. Clarification.
states, the temporary chiller as required. The design package system will be protected from states that if the chiller is deployed freezing. during winter months, steps should be taken to avoid freezing (e.g.,
draining lines when not in use, use of heat tape and insulation).
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Table 3 Item No. Description in NRC Audit Report Currently Planned Installation Reason for Change Significance 1 Page 4 of 7 of the Audit Report Permanent branch connections have To allow more efficient This new configuration states, Connection to the AHU been added to the AHU piping; (less time) transition is functionally coils will be made by isolating therefore, a current statement would between the temporary equivalent to the the chilled water piping, be, "Connection to the AHU coils is and permanent chillers configuration described removing the flex hoses between made via permanent flanged branch which will be in the LAR and is the AHU coils and the chilled connections with an isolation valve, advantageous during expected to benefit the water piping and then which were added as part of the the PMT window and project by reducing the reconnecting the temporary chiller replacement project should reduce time in time in the TS Required chilled water supply and return subsequent to the submittal of the the TS Required Action Action Completion hoses to the AHU coils using LAR." Completion Time. Time.
existing flange connections.
2 Page 5 of 7 of the Audit Report The CAT DG has a 300 gallon tank, To reflect the capacity The run time for the states, The temporary chiller which provides a 24-hour run time of the CAT DG which CAT DG is longer than skid DG fuel oil tanks capacity which is conservative compared to would be used with the the run time for the provides a 12-hour run time for the value cited here. Carrier chiller. Aggreko DG, which is the chiller skid without fuel oil conservative to what is replenishment, which allows the described in the Audit licensee time for replenishing Report.
measures.
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Schedule Milestones
- Request expedited NRC approval by August 1, 2023.
- 30-day implementation following NRC approval.
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