CNL-15-187, Response to NRC Request for Additional Information (RAI) Regarding Application to Revise Technical Specifications (TS) 3.3.6.1, Table 3.3.6.1-1 to Require Standby Liquid Control (SLC) System Instrumentation in
| ML15268A569 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 09/25/2015 |
| From: | James Shea Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BFN TS-479, CNL-15-187, TAC MF5748, TAC MF5749, TAC MF5750 | |
| Download: ML15268A569 (13) | |
Text
Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402 CNL-15-187 September 25, 2015 10 CFR 50.90 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Browns Ferry Nuclear Plant, Units 1, 2, and 3 Renewed Facility Operating License Nos. DPR-33, DPR-52, and DPR-68 NRC Docket Nos. 50-259, 50-260, and 50-296
Subject:
Response to NRC Request for Additional Information (RAI) Regarding Application to Revise Browns Ferry Nuclear Plant (BFN), Units 1, 2, and 3, Technical Specifications (TS) 3.3.6.1, Table 3.3.6.1-1 to require Standby Liquid Control (SLC) System Instrumentation in Additional Mode (BFN TS-479) (TAC Nos. MF5748, MF5749, MF5750)
References:
- 1. Letter from TVA to NRC, CNL-14-166, "Application to Revise BFN Units 1, 2, and 3 Technical Specifications 3.3.6.1, Table 3.3.6.1-1, Function 5.g and Bases (BFN-TS-479)," dated February 17, 2015 (ML15050A179)
- 2. Electronic Mail from NRC to TVA, RAI for Browns Ferry Application to require SLC instrumentation in additional mode (MF5748, MF5749, and MF5750), dated August 26, 2015 (ML15245A003)
By letter dated February 17, 2015 (Reference 1), Tennessee Valley Authority (TVA) submitted a license amendment request (LAR) for Browns Ferry Nuclear Plant (BFN),
Units 1, 2, and 3, to modify Technical Specification (TS) 3.3.6.1, Primary Containment Isolation Instrumentation, Table 3.3.6.1-1, to incorporate an additional mode of applicability for the Standby Liquid Control (SLC) System initiation instrumentation.
By electronic mail dated August 26, 2015 (Reference 2), the Nuclear Regulatory Commission (NRC) transmitted a request for additional information (RAI). The due date for the response to the RAI is September 25, 2015. The enclosure to this letter provides the TVA response to the RAI. As a result of the response, the proposed TS Bases changes provided for information in Reference 1 have been revised. The revised proposed TS Bases changes are included for information as attachments to the enclosure.
U.S. Nuclear Regulatory Commission CNL-15-187 Page 2 September 25, 2015 Consistent with the standards set forth in Title 10 of the Code of Federal Regulations (10 CFR), Part 50.92(c), TVA has determined that the additional information, as provided in this letter, does not affect the no significant hazards consideration determination associated with the request provided in Reference 1.
There are no new regulatory commitments contained in this submittal. Please address any questions regarding this submittal to Mr. Edward D. Schrull at (423) 751-3850.
I declare under penalty of perjury that the foregoing is true and correct. Executed on this 25th day of September 2015.
President, Nuclear Licensing
Enclosure:
Response to RAI Regarding Application to Revise Browns Ferry Nuclear Plant (BFN), Units 1, 2, and 3, Technical Specifications (TS) 3.3.6.1, Table 3.3.6.1-1 to require Standby Liquid Control (SLC) System Instrumentation in Additional Mode Attachments:
- 1. Revised Proposed Technical Specification Bases Pages Markups (for information only)
- 2. Revised Proposed Retyped Technical Specification Bases Pages (for information only) cc (Enclosure):
NRC Regional Administrator - Region II NRC Senior Resident Inspector - Browns Ferry Nuclear Plant NRC Project Manager - Browns Ferry Nuclear Plant NRC Branch Chief - Region II State Health Officer, Alabama State Department of Health
ENCLOSURE Response to RAI Regarding Application to Revise Browns Ferry Nuclear Plant (BFN),
Units 1, 2, and 3, Technical Specifications (TS) 3.3.6.1, Table 3.3.6.1-1 to require Standby Liquid Control (SLC) System Instrumentation in Additional Mode
NRC RAI STSB-01 The regulation at 10 CFR 50.36(c)(2) requires that Limiting Conditions for Operation (LCOs) be included in TSs. LCOs are the lowest functional capability or performance levels of equipment required for safe operation of a facility. LCOs must be established for items that meet one of four criteria contained in 10 CFR 50.36(c)(2)(ii). The regulations do not specify requirements for the contents of individual TSs.
The application states that the use of the SLCS [Standby Liquid Control system] to control suppression pool pH below 7 is further discussed in Final Safety Analysis Report Section 14.6.3.5. This FSAR section describes the use of the SLCS operation to add sodium pentaborate solution to the suppression pool water in order to maintain it below a pH of 7 following a LOCA event.
The NRC staff reviewed FSAR section 14.6.3.5. The FSAR section states that the buffering effect of SLCS injection within several hours is sufficient to offset the effects of these acids that are transported to the pool. Sufficient sodium pentaborate solution is available to maintain the suppression pool pH at or above 7.0 for 30 days post-accident. Section 3.8.1 of the FSAR states that the safety objective of the SLCS is to provide sufficient buffering agent to maintain the suppression pool pH at or above 7.0 following a DBA LOCA involving fuel damage. This is consistent with the safety evaluation for full scale implementation of the alternative source term amendment.
Please clarify (1) whether the post LOCA suppression pool pH is calculated to be below 7 or at or above 7; (2) clarify the SLC systems function in maintaining the post LOCA suppression pool pH; and (3) confirm that the calculated post LOCA suppression pool pH is consistent with the accident analysis assumptions.
TVA Response Please clarify (1) whether the post LOCA suppression pool pH is calculated to be below 7 or at or above 7.
The post-LOCA suppression pool pH is calculated to be at or above 7. The license amendment request (LAR) submitted in Reference 1 was in error. The discussion in the detailed description and technical evaluation sections regarding maintaining the suppression pool below a pH of 7 should have stated at or above a pH of 7 in each instance. This error has been entered into TVAs corrective action program as Condition Report 1080050.
The proposed TS Bases changes included for information in Reference 1 also contained this error. Revised proposed TS Bases changes are included for information as attachments to this enclosure. Attachment 1 contains the revised proposed TS Bases pages markups, and contains the revised proposed retyped TS Bases pages.
(2) clarify the SLC systems function in maintaining the post LOCA suppression pool pH The SLC system is credited in the radiological dose analysis for a LOCA to provide a buffering agent (sodium pentaborate solution) to the suppression pool water. The use of a buffering agent is needed to ensure that the suppression pool pH remains at or above 7.0 under worst case conditions for 30 days following a LOCA.
(3) confirm that the calculated post LOCA suppression pool pH is consistent with the accident analysis assumptions BFN Units 1, 2, and 3 licenses were amended in Reference 2 to adopt the alternative source term (AST) methodology. Analyses related to the radiological consequences of design basis accidents (DBAs), including a LOCA, were performed in support of these amendments. The LOCA analysis was performed in accordance with the guidance of Regulatory Guide (RG) 1.183 (Reference 3). Consistent with the source term assumptions prescribed in RG 1.183, the BFN AST LOCA analysis assumes that the iodine released to the containment is comprised of 95% cesium iodide (CsI), 4.85% elemental iodine, and 0.15% organic iodide. The safety evaluation enclosed in Reference 2 stated, the assumption of this iodine speciation is predicated on maintaining the containment sump water at pH 7.0 or higher.
The post-LOCA suppression pool pH has been calculated to remain above 7.0 for the duration of the DBA (30 days), confirming that the requirement for the iodine speciation assumption is met. Therefore, the post-LOCA suppression pool pH is consistent with the accident analysis assumptions.
References:
- 1.
Letter from TVA to NRC, "Application to Revise BFN Units 1, 2, and 3 Technical Specifications 3.3.6.1, Table 3.3.6.1-1, Function 5.g and Bases (BFN-TS-479)," dated February 17, 2015 (ML15050A179)
- 2.
Letter from NRC to TVA, Browns Ferry Nuclear Plant, Units 1, 2, and 3 -
Issuance of Amendments Regarding Full-Scope Implementation of Alternative Source Term (TAC Nos. MB5733, MB5734, MB5735, MC0156, MC0157, and MC0158) (TS-405), dated September 27, 2004 (ML042730028)
- 3.
Regulatory Guide 1.183, Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors, U.S. NRC Office of Nuclear Regulatory Research, July 2000
Revised Proposed Technical Specification Bases Pages Markups (for information only)
BASES APPLICABLE SAFETY ANALYSES, LCO, and APPLICABILITY (continued)
BFN-UNIT 1 Primary Containment Isolation Instrumentation B 3.3.6.1 5.g. SLC System Initiation The isolation of the RWCU System is required when the SLC System has been initiated to prevent dilution and removal of the boron solution by the RWCU System (Ref. 4 ). An isolation signal for both RWCU isolation valves is initiated when the SLC pump start handswitch is not in the stop position.
There is no Allowable Value associated with this Function since the channels are mechanically actuated based solely on the position of the SLC System initiation switch.
The SLC System Initiation Function is required to be OPERABLE only in MODES 1 and 2, since these are the only MODES where the reactor can be critical, and these MODES are consistent with the Applicability for the SLC System (LCO 3.1. 7).
As noted (footnote (a) to Table 3.3.6.1-1), the SLC initiation signal provides input to the isolation logic for both RWCU isolation valves.
5.h. Reactor Vessel Water Level - Low. Level 3 (LIS-3-203A-D)
Low RPV water level indicates that the capability to cool the fuel may be threatened. Should RPV water level decrease too far, fuel damage could result. Therefore, isolation of some interfaces with the reactor vessel occurs to isolate the potential sources of a break. The isolation of the RWCU System on Level 3 supports actions to ensure that the fuel peak cladding (continued)
B 3.3-206 Revision 0 and in MODE 3 because this MODE uses the SLC System sodium pentaborate as a buffering solution to maintain the pH level at or above 7 in the suppression pool in the event of a LOCA.
These because
BASES APPLICABLE SAFETY ANALYSES, LCO, and APPLICABILITY (continued)
BFN-UNIT 2 Primary Containment Isolation Instrumentation B 3.3.6.1 5.g. SLC System Initiation The isolation of the RWCU System is required when the SLC System has been initiated to prevent dilution and removal of the boron solution by the RWCU System (Ref. 4 ). An isolation signal for both RWCU isolation valves is initiated when the SLC pump start handswitch is not in the stop position.
There is no Allowable Value associated with this Function since the channels are mechanically actuated based solely on the position of the SLC System initiation switch.
The SLC System Initiation Function is required to be OPERABLE only in MODES 1 and 2, since these are the only MODES where the reactor can be critical, and these MODES are consistent with the Applicability for the SLC System (LCO 3.1.7).
As noted (footnote (a) to Table 3.3.6.1-1), the SLC initiation signal provides input to the isolation logic for both RWCU isolation valves.
5.h. Reactor Vessel Water Level - Low. Level 3 (LI S-3-203A-D)
Low RPV water level indicates that the capability to cool the fuel may be threatened. Should RPV water level decrease too far, fuel damage could result. Therefore, isolation of some interfaces with the reactor vessel occurs to isolate the potential sources of a break. The isolation of the RWCU System on Level 3 supports actions to ensure that the fuel peak cladding (continued)
B 3.3-209 Revision 0 and in MODE 3 because this MODE uses the SLC System sodium pentaborate as a buffering solution to maintain the pH level at or above 7 in the suppression pool in the event of a LOCA.
These because
BASES APPLICABLE SAFETY ANALYSES, LCO, and APPLICABILITY (continued)
BFN-UNIT 3 Primary Containment Isolation Instrumentation B 3.3.6.1 5.q. SLC System Initiation The isolation of the RWCU System is required when the SLC System has been initiated to prevent dilution and removal of the boron solution by the RWCU System (Ref. 4 ). An isolation signal for both RWCU isolation valves is initiated when the SLC pump start handswitch is not in the stop position.
There is no Allowable Value associated with this Function since the channels are mechanically actuated based solely on the position of the SLC System initiation switch.
The SLC System Initiation Function is required to be OPERABLE only in MODES 1 and 2, since these are the only MODES where the reactor can be critical, and these MODES are consistent with the Applicability for the SLC System (LCO 3.1. 7).
As noted (footnote (a) to Table 3.3.6.1-1), the SLC initiation signal provides input to the isolation logic for both RWCU isolation valves.
5.h. Reactor Vessel Water Level - Low. Level 3 (LIS-3-203A-D)
Low RPV water level indicates that the capability to cool the fuel may be threatened. Should RPV water level decrease too far, fuel damage could result. Therefore, isolation of some interfaces with the reactor vessel occurs to isolate the potential sources of a break. The isolation of the RWCU System on Level 3 supports actions to ensure that the fuel peak cladding B 3.3-209 (continued)
Amendment No. 213 September 03, 1998 and in MODE 3 because this MODE uses the SLC System sodium pentaborate as a buffering solution to maintain the pH level at or above 7 in the suppression pool in the event of a LOCA.
These because
Revised Proposed Retyped Technical Specification Bases Pages (for information only)
Primary Containment Isolation Instrumentation B 3.3.6.1 (continued)
BFN-UNIT 1 B 3.3-206 Revision 0, 00 BASES APPLICABLE 5.g. SLC System Initiation SAFETY ANALYSES, LCO, and The isolation of the RWCU System is required when the SLC APPLICABILITY System has been initiated to prevent dilution and removal of the (continued) boron solution by the RWCU System (Ref. 4). An isolation signal for both RWCU isolation valves is initiated when the SLC pump start handswitch is not in the stop position.
There is no Allowable Value associated with this Function since the channels are mechanically actuated based solely on the position of the SLC System initiation switch.
The SLC System Initiation Function is required to be OPERABLE in MODES 1 and 2, because these are the only MODES where the reactor can be critical, and in MODE 3 because this MODE uses the SLC System sodium pentaborate as a buffering solution to maintain the pH level at or above 7 in the suppression pool in the event of a LOCA. These MODES are consistent with the Applicability for the SLC System (LCO 3.1.7).
As noted (footnote (a) to Table 3.3.6.1-1), the SLC initiation signal provides input to the isolation logic for both RWCU isolation valves.
5.h. Reactor Vessel Water Level - Low, Level 3 (LIS-3-203A-D)
Low RPV water level indicates that the capability to cool the fuel may be threatened. Should RPV water level decrease too far, fuel damage could result. Therefore, isolation of some interfaces with the reactor vessel occurs to isolate the potential sources of a break. The isolation of the RWCU System on Level 3 supports actions to ensure that the fuel peak cladding
Primary Containment Isolation Instrumentation B 3.3.6.1 (continued)
BFN-UNIT 2 B 3.3-209 Revision 0, 00 BASES APPLICABLE 5.g. SLC System Initiation SAFETY ANALYSES, LCO, and The isolation of the RWCU System is required when the SLC APPLICABILITY System has been initiated to prevent dilution and removal of the (continued) boron solution by the RWCU System (Ref. 4). An isolation signal for both RWCU isolation valves is initiated when the SLC pump start handswitch is not in the stop position.
There is no Allowable Value associated with this Function since the channels are mechanically actuated based solely on the position of the SLC System initiation switch.
The SLC System Initiation Function is required to be OPERABLE in MODES 1 and 2, because these are the only MODES where the reactor can be critical, and in MODE 3 because this MODE uses the SLC System sodium pentaborate as a buffering solution to maintain the pH level at or above 7 in the suppression pool in the event of a LOCA. These MODES are consistent with the Applicability for the SLC System (LCO 3.1.7).
As noted (footnote (a) to Table 3.3.6.1-1), the SLC initiation signal provides input to the isolation logic for both RWCU isolation valves.
5.h. Reactor Vessel Water Level - Low, Level 3 (LIS-3-203A-D)
Low RPV water level indicates that the capability to cool the fuel may be threatened. Should RPV water level decrease too far, fuel damage could result. Therefore, isolation of some interfaces with the reactor vessel occurs to isolate the potential sources of a break. The isolation of the RWCU System on Level 3 supports actions to ensure that the fuel peak cladding
Primary Containment Isolation Instrumentation B 3.3.6.1 (continued)
BFN-UNIT 3 B 3.3-209 Amendment No. 213 Revision 00 BASES APPLICABLE 5.g. SLC System Initiation SAFETY ANALYSES, LCO, and The isolation of the RWCU System is required when the SLC APPLICABILITY System has been initiated to prevent dilution and removal of the (continued) boron solution by the RWCU System (Ref. 4). An isolation signal for both RWCU isolation valves is initiated when the SLC pump start handswitch is not in the stop position.
There is no Allowable Value associated with this Function since the channels are mechanically actuated based solely on the position of the SLC System initiation switch.
The SLC System Initiation Function is required to be OPERABLE in MODES 1 and 2, because these are the only MODES where the reactor can be critical, and in MODE 3 because this MODE uses the SLC System sodium pentaborate as a buffering solution to maintain the pH level at or above 7 in the suppression pool in the event of a LOCA. These MODES are consistent with the Applicability for the SLC System (LCO 3.1.7).
As noted (footnote (a) to Table 3.3.6.1-1), the SLC initiation signal provides input to the isolation logic for both RWCU isolation valves.
5.h. Reactor Vessel Water Level - Low, Level 3 (LIS-3-203A-D)
Low RPV water level indicates that the capability to cool the fuel may be threatened. Should RPV water level decrease too far, fuel damage could result. Therefore, isolation of some interfaces with the reactor vessel occurs to isolate the potential sources of a break. The isolation of the RWCU System on Level 3 supports actions to ensure that the fuel peak cladding