ML110600408

Technical Specification Change TS-429 - Deletion of Low Pressure Coolant Injection Motor-Generator Sets

ML110600408
Person / Time
Site:	Browns Ferry
Issue date:	02/25/2011
From:	Krich R Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML110600408 (51)

Text

Tennessee Valley Authority 1101 Market Street, LP 3R Chattanooga, Tennessee 37402-2801 R. M. Krich Vice President Nuclear Licensing February 25, 2011 10 CFR 50.90 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Browns Ferry Nuclear Plant, Units 2 and 3 Facility Operating License Nos. DPR-52 and DPR-68 NRC Docket Nos. 50-260 and 50-296

Subject:

Technical Specification Change TS-429 - Deletion of Low Pressure Coolant Injection Motor-Generator Sets for Browns Ferry Nuclear Plant, Units 2 and 3

Reference:

Letter from M. H. Chernoff (NRC) to K. Singer (TVA), "Browns Ferry Nuclear Plant, Unit 1 - Issuance of an Amendment Regarding Deletion of the Low Pressure Coolant Injection Motor-Generator Sets (TAC No. MC3822) (TS-427)," dated June 20, 2005 In accordance with the provisions of 10 CFR 50.90, "Application for amendment of license, construction permit or early site permit," Tennessee Valley Authority (TVA) is submitting a request for an amendment to the Technical Specifications (TS) for Browns Ferry Nuclear Plant (BFN), Units 2 and 3.

The proposed amendment would delete BFN, Units 2 and 3, TS Surveillance Requirement (SR) 3.5.1.12. SR 3.5.1.12. requires the verification of the capability to automatically transfer the power supply from the normal source to the alternate source for each Low Pressure Coolant Injection (LPCI) subsystem inboard injection valve and each recirculation pump discharge valve on a 24-month frequency. In addition, the BFN, Units 2 and 3, TS Bases 3.5.1, "ECCS - Operating," and TS Bases 3.8.7, "Distribution Systems -

Operating," are modified to reflect the disabling of this automatic transfer capability and the deletion of the LPCI Motor-Generator (MG) Sets. The NRC previously approved a similar request for BFN, Unit 1, in the reference letter.

The enclosure to this letter provides the evaluation for the proposed changes, the marked-up proposed TS and Bases pages, and the retyped proposed TS and Bases pages for BFN, Units 2 and 3. The evaluation for the proposed changes includes a description of the proposed changes, the technical evaluation, the no significant hazards determination, and the environmental evaluation.

printed on recycled paper

U.S. Nuclear Regulatory Commission Page 2 February 25, 2011 TVA has determined that there are no significant hazards considerations associated with the proposed change and that the proposed TS change qualifies for categorical exclusion from environmental review pursuant to the provisions of 10 CFR 51.22(c)(9). Additionally, in accordance with 10 CFR 50.91 (b)(1), "Notice for public comment; State consultation," a copy of this application, with attachments, is being provided to the designated State of Alabama official.

TVA requests the approval of the proposed License Amendments within one year of the date of this letter (i.e., by February 25, 2012), with the BFN, Unit 3, amendment being implemented prior to BFN, Unit 3, entering Mode 3 (i.e., Hot Shutdown) from the refueling outage currently scheduled to begin on April 1, 2012, and with the BFN, Unit 2, amendment being implemented prior to BFN, Unit 2, entering Mode 3 from the refueling outage currently scheduled to begin on February 18, 2013.

There is no new regulatory commitment in this license amendment request. If you should have any questions regarding this submittal, please contact Tom Matthews at (423) 751-2687.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on this 2 5 th day of February, 2011.

Respectfully, R. M. Krich

Enclosure:

Evaluation for Technical Specification Change TS-429, Deletion of Low Pressure Coolant Injection Motor-Generator Sets for Browns Ferry Nuclear Plant, Units 2 and 3 cc: NRC Regional Administrator - Region II NRC Senior Resident Inspector - Browns Ferry Nuclear Plant State Health Officer - Alabama Department of Public Health

ENCLOSURE EVALUATION FOR TECHNICAL SPECIFICATION CHANGE TS-429 Deletion of Low Pressure Coolant Injection Motor-Generator Sets for Browns Ferry Nuclear Plant, Units 2 and 3 1.0

SUMMARY

DESCRIPTION 2.0 DETAILED DESCRIPTION

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements/Criteria 4.2 Precedent 4.3 Significant Hazards Consideration 4.4 Conclusion

6.0 REFERENCES

ATTACHMENTS:

1. Proposed Technical Specifications and Bases Page Markups for BFN, Unit 2

2. Proposed Technical Specifications and Bases Page Markups for BFN, Unit 3

3. Retyped Proposed Technical Specifications and Bases Pages for BFN, Unit 2

4. Retyped Proposed Technical Specifications and Bases Pages for BFN, Unit 3 E-1

1.0

SUMMARY

DESCRIPTION This evaluation supports the proposal to amend Operating License DPR-52 for Browns Ferry Nuclear Plant (BFN), Unit 2 and Operating License DPR-68 for BFN, Unit 3. The proposed amendment would delete BFN, Units 2 and 3, Technical Specifications (TS) Surveillance Requirement (SR) 3.5.1.12. This SR requires the verification of the capability to automatically transfer the power supply from the normal source to the alternate source for each Low Pressure Coolant Injection (LPCI) subsystem inboard injection valve and each recirculation pump discharge valve on a 24-month frequency. In addition, the BFN Units 2 and 3 TS Bases 3.5.1, "ECCS - Operating," and TS Bases 3.8.7, "Distribution Systems - Operating," are modified to reflect the disabling of this automatic transfer capability and the deletion of the LPCI Motor-Generator (MG) Sets.

1.1 Equipment Historical Background The current design of BFN, Units 2 and 3, provided for automatic transfer of the power supply for the Low Pressure Coolant Injection (LPCI) inboard injection, Residual Heat Removal (RHR) minimum flow valves, and recirculation pump discharge valves to the alternate source when low voltage is detected on the primary source. The design included MG Sets (i.e., LPCI MG Sets) to provide electrical divisional isolation between the 1 E class normal and alternate power feeds to Reactor Motor-Operated Valve (RMOV) Boards D and E, while allowing for the operability of both Emergency Core Cooling System (ECCS) electrical trains when the power supply was swapped over. Currently, these LPCI MG Sets for BFN, Unit 2, and BFN, Unit 3, are obsolete and are high maintenance equipment.

1.2 Design and Licensing Bases Currently, BFN, Units 2 and 3, RMOV Boards D and E automatically transfer the power supply from the normal source to the alternate source upon detection of low voltage at the normal power source. The automatic transfer of the power supply for the LPCI inboard injection valves, RHR minimum flow valves, and recirculation pump discharge valves was once a requirement to comply with 10 CFR 50 Appendix K, "ECCS Evaluation Models," and 10 CFR 50.46, "Acceptance criteria for emergency core cooling systems for light-water nuclear power reactors,"

using older LOCA analysis methods.

Based on improved Loss of Coolant Accident (LOCA) analysis methods, the automatic transfer of power is no longer required. This is demonstrated in the AREVA LOCA Break Spectrum Analysis for BFN, Units 1, 2, and 3 (Reference 1). This analysis does not require the automatic transfer of the power supply for the LPCI inboard injection valves, RHR minimum flow valves, and recirculation pump discharge valves.

10 CFR 50.46 regulatory requirements are met by the use of two independent electrical power divisions for the ECCS equipment.

Deletion of the requirement for the automatic transfer function of RMOV Boards D and E will not change the number of ECCS subsystems credited in the current BFN licensing basis for BFN, Units 2 or BFN, Unit 3 since the automatic transfer function is no longer credited for the BFN LOCA Break Spectrum Analysis.

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2.0 DETAILED DESCRIPTION The proposed change eliminates the requirement to maintain an automatic transfer capability for the power supply to the LPCI inboard injection valves, RHR minimum flow valves and recirculation pump discharge valves. The specific proposed TS changes are described below.

The associated TS Bases changes are provided for information.

2.1 Proposed Technical Specification Changes The proposed change is to delete TS SR 3.5.1.12 for BFN, Units 2 and 3. This SR requires the verification of the capability to automatically transfer the power supply from the normal source to the alternate source for each LPCI subsystem inboard injection valve and each recirculation pump discharge valve on a 24-month frequency. In addition, TS Bases 3.5.1 and 3.8.7 for BFN, Units 2. and 3, are modified to reflect the disabling of the automatic transfer capability and any reference to the LPCI MG Sets.

The Tennessee Valley Authority (TVA) is requesting that TS SR 3.5.1.12 for BFN, Units 2 and 3, be deleted to support a modification to allow for the removal of the LPCI MG Sets. LPCI MG Sets, which were once a requirement for electrical divisional isolation between the Class 1E normal and alternate power feeds to RMOV Boards D and E, while allowing for the operability of both ECCS electrical trains when the power supply is swapped over, will be removed from service since the automatic transfer function is no longer credited for the BFN LOCA Break Spectrum Analysis. BFN, Units 2 and 3, RMOV Boards D and E will be connected directly to their power supplies with both of the alternate supply breakers normally open to provide isolation between electrical divisions.

TVA received approval of a similar TS change to support the deletion of the automatic transfer function and the associated LPCI MG Sets on June 20, 2005 (Reference 2) for BFN, Unit

1. The BFN, Unit 1, LPCI MG Sets and their RMOV Boards 1 D and 1 E were then removed from service. For BFN, Unit 1, loads that were once on RMOV Boards 1D and 1E are now powered from BFN, Unit 1, RMOV Boards A and B.

However, BFN, Units 2 and 3, will retain their RMOV boards in the proposed modification, which will eliminate the LPCI MG Sets. Currently, the BFN, Units 2 and 3 RMOV Boards D and E are being powered by the LPCI MG Sets. After the modification, the BFN, Units 2 and 3, RMOV Boards D and E will be powered directly from the 480V Shutdown Boards. Loads presently on BFN, Units 2 and 3, RMOV Boards D and E will remain on the respective RMOV boards.

Mark-ups of the proposed changes to the TS and Bases are provided in Attachments 1 and 2 for BFN, Units 2 and 3, respectively. Attachments 3 and 4 provide the retyped TS and Bases pages reflecting the incorporation of the proposed changes for BFN, Units 2 and 3, respectively.

TVA requests the approval of the proposed License Amendments within one year of the date of this letter (i.e., by February 25, 2012), with the BFN, Unit 3, amendment being implemented prior to BFN, Unit 3, entering Mode 3 (i.e., Hot Shutdown) from the refueling outage currently scheduled to begin on April 1, 2012, and with the BFN, Unit 2, amendment being implemented prior to BFN, Unit 2, entering Mode 3 from the refueling outage currently scheduled to begin on February 18, 2013.

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3.0 TECHNICAL EVALUATION

3.1 Current Electrical Distribution System BFN is a three-unit plant. As discussed in Updated Final Safety Analysis Report (UFSAR)

Sections 8.4, "Normal Auxiliary Power System," and 8.5, "Standby AC Power Supply and Distribution," there are several sources of offsite and onsite power for BFN.

During normal operation, station auxiliary power is taken from the main generator through the unit station service transformers. During startup and shutdown, auxiliary power is supplied from the 500-kV system through the main transformers to the unit station service transformer with the main generators isolated by the main generator breakers. Auxiliary power is also available through the two common station service transformers which are fed from the 161-kV system.

Standby (onsite) power is supplied by eight diesel generator units (four for BFN Units 1 and 2, and four for BFN, Unit 3).

There are five 480V RMOV Boards (A through E) powered by 480V Shutdown Boards A and B for BFN, Unit 2, and BFN, Unit 3. The 480V RMOV Boards A and D are normally powered from 480V Shutdown Board A with Division I power. The 480V Shutdown Board B is the alternate power supply. The 480V RMOV Boards B, C and E are normally powered from 480V Shutdown Board B with Division II power. The 480V Shutdown Board A is the alternate power supply.

(Note that the designations used for the boards, valves and MG Sets in the text of this submittal have been generalized to improve readability. The actual RMOV board designations are 2A through 2E on BFN, Unit 2, and 3A through 3E on BFN, Unit 3. The valves and MG Set designations are also prefixed with the associated unit number.)

Currently, power to BFN, Unit 2, and BFN, Unit 3, 480V RMOV Boards D and E are supplied from 480V Shutdown Boards A and B via MG Sets. There are four MG Sets in BFN, Unit 2, and four in BFN, Unit 3. Two MG Sets are fed from 480V Shutdown Board A and act as a normal power source for 480V RMOV Board D (MG Set DN) and as an alternate power source to 480V RMOV Board E (MG Set EA). Two MG Sets are fed from 480V Shutdown Board B and act as a normal power source for 480V RMOV Board E (MG Set EN) and as an alternate power source to 480V RMOV Board D (MG Set DA).

Currently, BFN, Unit 2, and BFN, Unit 3, 480V RMOV Boards D and E automatically transfer the power supply from the normal source to the alternate source upon detection of an under voltage condition from the normal source. The MG Sets act as electrical isolators to prevent a fault from propagating between electrical divisions during an automatic transfer.

The 480V RMOV Board D provides Division I power to the following loads:

• Flow Control Valve (FCV) 68-79, Recirculation Pump Discharge Valve;

• FCV-74-7, RHR Pumps A and C Minimum Flow Bypass Valve; and

• FCV-74-53, RHR LPCI Injection Valve.

The 480V RMOV Board E provides Division II power to the following loads:

• FCV-68-3, Recirculation Pump Discharge Valve;

• FCV-74-30, RHR Pumps B & D Minimum Flow Bypass Valve; and

• FCV-74-67, RHR LPCI Injection Valve.

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3.2 Design of the Emergency Core Cooling System The BFN ECCS consists of the following:

" High Pressure Coolant Injection (HPCI);

" Automatic Depressurization System (ADS);

• Low Pressure Core Spray (LPCS); and

• LPCI, which is an operating mode of RHR.

The ECCS subsystems are designed to limit clad temperature over the complete spectrum of possible break sizes in the nuclear system process barrier, including the design basis break.

The design basis break is defined as the complete and sudden circumferential rupture of the largest pipe connected to the reactor vessel (i.e., one of the recirculation loop pipes) with displacement of the ends so that blow down occurs from both ends.

The low-pressure ECCS consists of LPCS and LPCI. The LPCS consists of two independent loops. Each loop consists of two pumps, a spray sparger inside the core shroud and above the core, piping, and valves to convey water from the pressure suppression pool to the sparger, and the associated controls and instrumentation. When the system is actuated, water is taken from the pressure suppression pool. Flow then passes through a normally open motor-operated valve in the suction line to each 50% capacity pump.

The RHR System is designed for five modes of operation (i.e., shutdown cooling, containment spray and suppression pool cooling, LPCI, standby cooling, and supplemental fuel pool cooling).

During LPCI operation, four RHR pumps take suction from the pressure suppression pool and discharge to the reactor vessel into the core region through both of the recirculation loops. Two pumps discharge to each recirculation loop.

The design function for the equipment powered from BFN, Unit 2, and BFN, Unit 3, 480V RMOV Boards D and E is as follows.

• Recirculation Pump Discharge Valves (FCV-74-79 and 3) - After receipt of a LPCI initiation signal, a signal is transmitted to the recirculation pump discharge valve control logic in each loop of the Recirculation System to close each valve once the reactor vessel pressure has sufficiently decreased.

• RHR Pump Minimum Flow Bypass Valves (FCV-74-7 and 30) - The RHR pump minimum flow bypass line header isolation valves are automatically controlled by control logic to start or stop flow through the two RHR pump minimum flow bypass lines of the associated loop. The isolation valve is automatically opened if its associated loop injection flow is less than approximately 3,500 gpm, concurrent with indication that either of the two RHR pumps in the respective loop is running. The isolation valve is automatically closed if its associated loop injection flow is greater than the set point.

• RHR Inboard Valves (FCV-74-53 and 67) - The RHR Inboard Valves are opened upon receipt of a LPCI initiation signal once the reactor vessel pressure has sufficiently decreased.

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3.3 Historical Basis for the Electrical and Emergency Core Cooling Systems Design As discussed in UFSAR Section 1.5, "Principal Design Criteria," sufficient redundancy and independence is provided for essential safety functions to ensure that no single failure of active components can prevent the required actions. For systems or components to which IEEE-279, "Criteria for Protection Systems for Nuclear Power Generating Stations," is applicable, single failures of passive electrical components are also considered.

Following initial startup and operation, the electrical system design was modified to satisfy the more stringent limitations required by 10 CFR 50, Appendix K, and to resolve other regulatory issues (late 1970s). BFN was using the General Electric (GE) SAFE/CHASTE/REFLOOD LOCA analysis methodology when it modified the ECCS logic. In order to obtain acceptable results utilizing the SAFE/CHASTE/REFLOOD LOCA analysis methodology, TVA had to ensure that at least one RHR pump would be operating in each LPCI loop prior to the postulated single failure to mitigate the consequences of a recirculation suction line break.

The automatic transfer capability for BFN, Unit 2, and BFN, Unit 3, 480V RMOV Boards D and E was designed to ensure that the LPCI injection occurred from both loops with at least one pump in each loop. If one loop's LPCI injection valve (either FCV-74-53 or FCV-74-67), RHR minimum flow valves (FCV-74-7 and 30) and the associated reactor recirculation loop discharge valve (either FCV-68-79 or FCV-68-3) lost power (from either 480V RMOV Boards D or E), the RMOV board would automatically transfer to the opposite division's power supply to ensure operation of the valves. With this transfer scheme in place, TVA was concerned that the automatic transfer could propagate an electrical fault to both divisions of power supply. As a result, BFN, Unit 2 and BFN, Unit 3 LPCI MG Sets were included in the design for both the normal and alternate power supplies to provide electrical isolation between the associated 480V Shutdown Board and the RMOV Board.

In 1996, TVA replaced the SAFE/CHASTE/REFLOOD LOCA analysis methodology with the SAFER/GESTR-LOCA methodology. The plant specific analysis to support the change to the SAFER/GESTR model and the associated TS changes were provided to NRC in per References 3 and 4. NRC issued the change in Reference 5. With the change to SAFER/GESTR, the BFN LOCA analyses no longer credited the automatic transfer of power for LPCI.

3.4 Description of Current Emergency Core Cooling System Performance Analysis BFN, Units 2 and 3, currently use AREVA fuel, supported by the EXEM BWR-2000 Evaluation Model which has been approved for licensing analysis by the NRC and conforms directly to 10 CFR 50, Appendix K. As with the earlier GE LOCA analyses using SAFER/GESTR, AREVA has not taken credit for the LPCI automatic transfer mechanism in their analyses for BFN.

Results of the AREVA analyses of record for LOCA are provided in References 1 and 6.

Reference 7 provided the results of these analyses to the NRC. Operational equipment assumptions for the analyses of record are shown in Table 1, "Available BFN ECCS for Recirculation Line Break LOCAs." Terminology for assumed single failures (SF) used in Table 1 is as follows.

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• Backup battery power (SF-BATT) o Unit Battery supplying 250VDC RMOV Board 1A, 2A, or 3A (SF-BATTIBA) o Unit Battery supplying 250VDC RMOV Board 1B, 2B, or 3B Board B (SF-BATTIBB) o Unit Battery supplying 250VDC RMOV Board 1C, 2C, or 3C Board C (SF-BATTIBC)

Note: There are three Unit Batteries (1, 2, and 3) shared between the three BFN units and supplying power to the 250VDC RMOV Boards.

" Opposite unit false LOCA signal (SF-LOCA)

" LPCI valve (SF-LPCI)

• Diesel Generator (SF-DGEN)

• HPCI System (SF-HPCI)

• ADS (SF-ADS) o Failure of ADS initiation logic (SF-ADSIIL) o Failure of a single ADS valve (SF-ADSISV)

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Table 1, Available BFN ECCS for Recirculation Line Break LOCAs Systems* t Assumed Failure Remaining Recirculationt Recirculation Suction Break Discharge Break SF-BATTIBA 6 ADS, 1 LPCS, 2 LPCI 6 ADS, 1 LPCS SF-BATTIBB HPCI, 1 LPCS, 2 LPCI, Manual ADS5 HPCI, 1 LPCS, Manual ADS SF-BATTIBC** 4 ADS, HPCI, 1 LPCS, 3 LPCI 4 ADS, HPCI, 1 LPCS, 1 LPCI SF-LOCA 6 ADS, HPCI, 1 LPCS, 2 LPCI 6 ADS, HPCI, 1 LPCS SF-LPCI 6 ADS, HPCI, 2 LPCS, 2 LPCI 6 ADS, HPCI, 2 LPCS SF-DGEN 6 ADS, HPCI, 1 LPCS, 2 LPCI 6 ADS, HPCI, 1 LPCS SF-HPCI 6 ADS, 2 LPCS, 4 LPCI 6 ADS, 2 LPCS, 2 LPCI SF-ADSIIL HPCI, 2 LPCS, 4 LPCI, Manual ADS HPCI, 2 LPCS, 2 LPCI, Manual ADS SF-ADSISV 5 ADS, HPCI, 2 LPCS, 4 LPCI 5 ADS, HPCI, 2 LPCS, 2 LPCI Each LPCS means operation of two core spray pumps in a system. It is assumed that both pumps in a system must operate to take credit for core spray cooling or inventory makeup.

Furthermore, 2 LPCI refers to two LPCI pumps into one loop, 3 LPCI refers to two LPCI pumps into one loop and one LPCI pump into one loop. 4 LPCI refers to four LPCI pumps into two loops, two per loop.

t 4 ADS, 5 ADS and 6 ADS means the number of ADS valves available for automatic activation.

Systems remaining, as identified in this table for recirculation suction line breaks, are applicable to other non-ECCS line breaks. For a LOCA from an ECCS line break, the systems remaining are those listed for recirculation suction breaks, less the ECCS in which the break is assumed.

§ Manual ADS means 4 ADS valves are available to be opened manually. The analyses assume the 4 valves are opened 10 minutes after the break occurs.

BFN, Unit 3, systems remaining. Conservative for BFN, Units 1 and 2.

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3.5 Proposed Change to the Electrical Distribution System The following changes will be made to the Electrical Distribution System:

1. BFN, Units 2 and 3, LPCI MG Sets DN, DA, EN, and EA and their locally mounted instrumentation and controls will be removed from service and abandoned in place.

2. Instead of RMOV Boards D and E being powered from the LPCI MG Sets, they will be powered directly from the corresponding 480V Shutdown Boards through their normal feeds.

3. The feeder breakers for 480V RMOV Boards D and E at the applicable 480V Shutdown Boards will be modified from electrically operated to mechanically operated.

4. The alternate feeder breakers for 480V RMOV Boards D and E at the applicable 480V Shutdown Boards will be changed from normally closed to normally open.

The current configuration of the portion of the electrical distribution system associated with this proposed change is shown in Figures 1 and 3 for BFN, Units 2 and 3, respectively.

After the proposed change, the resulting configuration of the portion of the electrical distribution system associated with this proposed change will be as shown in Figures 2 and 4 for BFN, Units 2 and 3, respectively.

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Figure 1, Current Configuration of Portion of BFN, Unit 2, Electrical Distribution System Associated with Proposed Change 480V REALCTOR MOV OD 2E (2-45E751 -11 E-10

Figure 2, Resulting Configuration of Portion of BFN, Unit 2, Electrical Distribution System Associated with Proposed Change 480V REACTORMOD'SD 2E (2-45E751-11 )

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Figure 3, Current Configuration of Portion of BFN, Unit 3, Electrical Distribution System Associated with Proposed Change 01EStI. GEN 32508VA 3A, 4.16KV.

CONTINUOUS. 0.OPF DIESEL GEN 3B. 4,16KV.

3 50KVA CONTINUOUS.0,8PF DIESEL CEI4 3C. 4.IKAV.

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~4V SHUTDON4VSUOOWN 12 ~ d 0H BR11 4KV SHUDW-8 BODVA 1200A BOB aBsoC 2000k (0-13200A1 120E200A(-IEOO1 NO)8.38 N0)844 26 M)3NC36N 72 N 84 0)62 NO$2 N)43 NO 26 N 38 NG32

• K SUTON2DIE *KV SHT7Ž OWN S 34 O E9 4KVSHUTDOWN8 9 (3-4E72n6)J3-4E72_, 3'45E724'-8) j2 8.00t KVA A Aý1333/V j~ 8 S 50 KVA Tw /I33. KAVI

-. 0 N) 480V SHUTDOWN O0 3A NO) NO) 480V SmUToOvW s0 i8 f3-4SE749-5) T  ? (3-45C749-6)

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OT MOTOR GENERATOR L4O1 MOT IN U. 460V, REACTOR MOV80 3A 3 ,. 60Hz (3-45E751-1&2I MO0T 89 SPECIAL OUTPUT, 48DV.

• .RKVA, D.SPE GENd G Nd NO) NC GEN G 480V REACTOR MDV 80 38 (3-45E751-3&4)

Ir; 480V REACTOR MOV 9D 3C NO)

NC) NO 480V REACTOR MOV 8D 10 (3-45E7il-9)

NO)

NO) 480V REACTOR MOV 80.3E .

(3-45E721-12)

NC) HO0) 48OV DIESEL AUX.8D .3EA (3-450322-5) 480V COMMON 80 3 410)

BUS A 480V DIESEL AUX RD3EB (o-5E 500oo (3-4SE722-G)

NO) NC) 460V CONTROL. BAT VENT;80 N 6

S (J NC-(O-45E736-2)

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Figure 4, Resulting Configuration of Portion of BFN, Unit 3, Electrical Distribution System Associated with Proposed Change DIESEL OrE 3A. 4,1SKV.

32 SMVA CONTINUOUS,O~gff 480Y COA4OE DO 3 (0-IS500O-'2)

(3-45E732-6)

No) .

480v CONTROL eAY VE!N1T NC)I-J ,I ,,

(045V76-2)

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3.6 Evaluation of Proposed Change on the Electrical Distribution System Altering the configuration as proposed above has the potential for introducing different failure modes than were previously considered. A failure modes evaluation was performed, which concluded that there will be no adverse effects as a result of the proposed changes. The design function of the LPCI MG Sets was to provide electrical isolation between redundant divisions of the electrical distribution system in the event of a malfunction of the automatic transfer of 480V RMOV Boards D or E resulting in both normal and alternate supply breakers being closed at the same time. Without the LPCI MG Sets in the circuit, this malfunction would have allowed a fault to propagate from one division to the other. The new electrical system configuration eliminates that concern by changing the alternate feeder breakers for 480V RMOV Boards D and E at the applicable 480V Shutdown Boards from normally closed to normally open. These breakers will be modified to not automatically transfer, which ensures the redundant divisions remain electrically isolated from each other.

TVA's proposed change is in conformance with 10 CFR 50.55a(h)(2), "Protection systems," and the BFN licensing basis. The BFN licensing basis for ECCS protection systems is described in UFSAR Sections 8.9, "Safety Systems Independence Criteria and Bases for Electrical Cable Installation," and 7.4, "Emergency Core Cooling Control and Instrumentation." These systems are designed to meet the intent of the Institute of Electrical and Electronics Engineers (IEEE) proposed Criteria for Protection Systems for Nuclear Power Generating Stations (IEEE-279-1971).

3.7 Effect of Proposed Change on Actual Emergency Core Cooling System Performance and the Loss of Coolant Accident (LOCA) Analysis Once the proposed change is implemented, the loads powered from 480V RMOV Board D or E will not automatically transfer to continue to receive power. Available ECCS equipment, considering various single failure scenarios, and taking into account actual LOCA analyses assumptions, are described in Table 2, "ECCS Equipment Available and Credited in the LOCA Analysis for a Recirculation Suction Line Break Before and After the Proposed Change," and Table 3, "ECCS Equipment Available and Credited in the LOCA Analysis for a Recirculation Discharge Line Break Before and After the Proposed Change."

The ECCS equipment available following the postulated pipe break and single failure were determined by performing an analysis based on the physical configuration of the ECCS. The analysis started with the identification of ECCS equipment available prior to the postulated break. Then, each of the postulated break locations was evaluated. (Note: Break location plays a part in the analysis because the recirculation pump discharge pipe break results in the direct loss of a LPCI loop, whereas recirculation pump suction pipe breaks do not result in the direct loss of any ECCS pump capability.) A loss of offsite power was also postulated to occur. One active single failure within the plant is postulated to occur concurrent with the pipe break. The single failure was determined based on ensuring that it results in the largest amount of equipment being lost. (For example, if two LPCI pumps (one loop) were lost as a result of the break location, a Diesel Generator supplying power to another pump in the opposite (unbroken) recirculation loop was selected as the single failure. This resulted in the largest amount of equipment lost due to the single failure). This analytical approach resulted in the identification of the minimum equipment remaining available for postulated break mitigation.

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The proposed change does not affect available equipment for eight of the nine most limiting postulated failures evaluated in the current LOCA analyses:

• The failure of unit battery board A (SF-BATTIBA);

" The failure of unit battery board B (SF-BATTIBB);

• The failure'of unit battery board C (SF-BATTIBC);

• A spurious LOCA signal from another unit (SF-LOCA);

• The failure of a LPCI injection valve (SF-LPCI);

• The failure of the HPCI System (SF-HPCI);

• The failure of ADS initiation logic (SF-ADSIIL); or

• The failure of a single ADS valve (SF-ADSISV).

The ninth limiting postulated failure is a LOCA (suction or discharge line break), without offsite power available, and the loss of a diesel generator is the assumed single failure. The scenario will cause the loss of power to either 480V RMOV Boards A and D or B and E. After the proposed change is implemented, the loads powered from 480V RMOV Board D or E will not automatically transfer to receive power. Therefore, there will be one less LPCI pump actually available for injection into the vessel. However, as indicated in Tables 2 and 3, the proposed change results in the same number of LPCI components available as is credited in the References 1 and 6 analyses of record.

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Table 2, ECCS Equipment Available and Credited in the LOCA Analysis for a Recirculation Suction Line Break Before and After the Proposed Change Assumed Failure ECCS Systems ECCS Systems ECCS Systems ECCS Systems Actually Available Actually Available Credited In the Credited In the Before the Proposed After the Proposed Analysis Analysis Change Change Before the Change After the Change SF-BATTIBA 6 ADS, 1 LPCS, 2 LPCI (Same as available before 6 ADS, 1 LPCS, 2 LPCI (Same as credited before the proposed change) the proposed change)

SF-BATTIBB HPCI, 1 LPCS, 2 LPCI, (Same as available before HPCI, 1 LPCS, 2 LPCI, (Same as credited before Manual ADS the proposed change) Manual ADS the proposed change)

SF-BATTIBC 4 ADS, HPCI, 1 LPCS, 3 (Same as available before 4 ADS, HPCI, 1 LPCS, 3 (Same as credited before LPCI the proposed change) LPCI the proposed change)

SF-LOCA 6 ADS, HPCI, 1 LPCS, 2 (Same as available before 6 ADS, HPCI, 1 LPCS, 2 (Same as credited before LPCI the proposed change) LPCI the proposed change)

SF-LPCI 6 ADS, HPCI, 2 LPCS, 2 (Same as available before 6 ADS, HPCI, 2 LPCS, 2 (Same as credited before LPCI the proposed change) LPCI the proposed change)

SF-DGEN 6 ADS, HPCI,1 LPCS, 3 6 ADS, HPCI,1 LPCS, 2 6 ADS, HPCI,1 LPCS, 2 (Same as credited before LPCI LPCI LPCI the proposed change)

SF-HPCI 6 ADS, 2 LPCS, 4 LPCI (Same as available before 6 ADS, 2 LPCS, 4 LPCI (Same as credited before the proposed change) the proposed change)

SF-ADSIIL HPCI, 2 LPCS, 4 LPCI, (Same as available before HPCI, 2 LPCS, 4 LPCI, (Same as credited before Manual ADS the proposed change) Manual ADS the proposed change)

SF-ADSISV 5 ADS, HPCI, 2 LPCS, 4 (Same as available before 5 ADS, HPCI, 2 LPCS, 4 (Same as credited before LPCI the proposed change) LPCI the proposed change)

E-1 6

Table 3, ECCS Equipment Available and Credited in the LOCA Analysis for a Recirculation Discharge Line Break Before and After the Proposed Change Assumed Failure ECCS Systems ECCS Systems ECCS Systems ECCS Systems Actually Available Actually Available Credited In the Credited In the Before the Proposed After the Proposed Analysis Analysis Change Change Before the Change After the Change SF-BATTIBA 6 ADS, 1 LPCS (Same as available before 6 ADS, 1 LPCS (Same as credited before the proposed change) the proposed change)

SF-BATTIBB HPCI, 1 LPCS, Manual (Same as available before HPCI, 1 LPCS, Manual (Same as credited before ADS the proposed change) ADS the proposed change)

SF-BATTIBC 4 ADS, HPCI, 1 LPCS, 1 (Same as available before 4 ADS, HPCI, 1 LPCS, 1 (Same as credited before LPCI the proposed change) LPCI the proposed change)

SF-LOCA 6 ADS, HPCI, 1 LPCS (Same as available before 6 ADS, HPCI, 1 LPCS (Same as credited before the proposed change) the proposed change)

SF-LPCI 6 ADS, HPCI, 2 LPCS (Same as available before 6 ADS, HPCI, 2 LPCS (Same as credited before the proposed change) the proposed change)

SF-DGEN 6 ADS, HPCI,1 LPCS, 1 6 ADS, HPCI,1 LPCS 6 ADS, HPCI,1 LPCS (Same as credited before LPCI the proposed change)

SF-HPCI 6 ADS, 2 LPCS, 2 LPCI (Same as available before 6 ADS, 2 LPCS, 2 LPCI (Same as credited before the proposed change) the proposed change)

SF-ADSIIL HPCI, 2 LPCS, 2 LPCI, (Same as available before HPCI, 2 LPCS, 2 LPCI, (Same as credited before Manual ADS the proposed change) Manual ADS the proposed change)

SF-ADSISV 5 ADS, HPCI, 2 LPCS, 2 (Same as available before 5 ADS, HPCI, 2 LPCS, 2 (Same as credited before LPCI the proposed change) LPCI the proposed change)

E-1 7

3.8 Technical Evaluation Summary In summary, the automatic transfer of the power supply for the LPCI inboard injection valves, RHR minimum flow valves and recirculation pump discharge valves is not required to meet the modeling of these components in the safety analyses (LOCA). Regulatory requirements are met by the use of two independent divisions of ECCS equipment. Disabling of the automatic transfer function will not change the number of ECCS subsystems credited in the current BFN licensing basis.

The BFN, Unit 2, and BFN, Unit 3, 480V RMOV Boards D and E will be powered directly from the applicable 480V Shutdown Boards. This electrical alignment has been analyzed and determined to be acceptable for BFN, Unit 2, and BFN, Unit 3.

The results of the deterministic evaluation provided in Sections 3.6 and 3.7 assure that the equipment required to safely shutdown the plant and mitigate the effects of a design basis accident, transient, or special event, will remain capable of performing their safety function with the deletion of the requirement to maintain an automatic transfer capability for the power supply to the LPCI inboard injection valves, RHR minimum flow valves and recirculation pump discharge valves.

4.0 REGULATORY EVALUATION

TVA is submitting a TS change request to licenses DPR-52 and DPR-68 for BFN, Unit 2, and BFN, Unit 3. The proposed TS change removes the requirement to maintain an automatic transfer capability for the power supply to the LPCI inboard, injection valves, RHR minimum flow valves and recirculation pump discharge valves.

4.1 Applicable Regulatory Requirements/Criteria The proposed deletion of the requirement for an automatic transfer of the power supply to the LPCI inboard injection valves, RHR minimum flow valves and recirculation pump discharge valves does not alter compliance with the requirements of 10 CFR 50, Appendix A, General Design Criterion 17, "Electric Power Systems," or the guidelines in Regulatory Guide 1.9, "Selection, Design, Qualification, and Testing of Emergency Diesel Generator Units Used as Class IE Onsite Electric Power Systems at Nuclear Power Plants."

TVA's proposed change is in conformance with 10 CFR 50.55a(h)(2) and the BFN licensing basis. The BFN licensing basis for ECCS protection systems is described in UFSAR Sections 8.9, "Safety Systems Independence Criteria and Bases for Electrical Cable Installation," and 7.4, "Emergency Core Cooling Control and Instrumentation." These systems are designed to meet the intent of the IEEE proposed Criteria for Protection Systems for Nuclear Power Generating Stations (IEEE-279-1971).

The Normal Auxiliary Power System, Emergency AC Power System and the proposed electrical distribution system will support the electrical loads necessary to mitigate the consequences of a design basis accident. The proposed deletion of the requirement to maintain an automatic transfer capability for the power supply to the LPCI inboard injection valves, RHR minimum flow valves and recirculation pump discharge valves does not change the number of ECCS subsystems credited in the BFN licensing basis. Therefore, the requirements of 10 CFR 50.46 and Appendix K continue to be met.

E-18

4.2 Precedent The NRC has previously approved a similar change for the following plant.

"Browns Ferry Nuclear Plant, Unit 1 - Issuance of an Amendment Regarding Deletion of the Low Pressure Coolant Injection Motor-Generator Sets (TAC No. MC3822)(TS-427)," dated June 20, 2005. (ML051580047) 4.3 Significant Hazards Consideration The Tennessee Valley Authority (TVA) is submitting a Technical Specifications (TS) change request to licenses DPR-52 and DPR-68 for Browns Ferry Nuclear Plant (BFN), Unit 2, and BFN, Unit 3. The proposed TS change removes the requirement to maintain an automatic transfer capability for the power supply to the Low Pressure Coolant Injection (LPCI) inboard injection valves, Residual Heat Removal (RHR) minimum flow valves and recirculation pump discharge valves.

TVA has evaluated whether or not a significant hazards consideration is involved with the proposed TS changes by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of Amendment," as discussed below:

1. Does the proposed Technical Specification change involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No The 480V RMOV Boards D or E, the equipment they power, or the automatic power transfer feature provided for these boards are not precursors to any accident previous evaluated in the Updated Final Safety Analysis Report (UFSAR). Therefore, the probability of an evaluated accident is not increased by modifying this equipment.

The proposed deletion of the requirement to maintain the automatic transfer capability for the power supply to the LPCI inboard injection valves, RHR minimum flow valves and recirculation pump discharge valves does not change the number of Emergency Core Cooling System (ECCS) subsystems credited in the BFN licensing basis. The proposed change does not affect the operational characteristics or function of systems, structures, or components (SSCs), the interfaces between credited SSCs and other plant systems, or the reliability of SSCs. The proposed change does not impact the capability of credited SSCs to perform their required safety functions.

Therefore, the proposed TS changes will not significantly increase the consequences of an accident previously evaluated.

E-19

2. Does the proposed Technical Specification change create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No The proposed deletion of the requirement to maintain an automatic transfer capability for the power supply to the LPCI inboard injection valves, RHR minimum flow valves and recirculation pump discharge valves does not introduce new equipment, which could create a new or different kind of accident.

The proposed change does not alter the manner in which equipment operation is initiated, nor will the functional demands on credited equipment be changed. The capability of credited SSCs to perform their required function will not be affected by the proposed change. In addition, the proposed change does not affect the interaction of plant SSCs with other plant SSCs whose failure or malfunction can initiate an accident or transient. As such, no new failure modes are being introduced. No new external threats, release pathways, or equipment failure modes are created. Therefore, the proposed deletion of the requirement to maintain an automatic transfer capability for the power supply to the LPCI inboard injection valves, RHR minimum flow valves and recirculation pump discharge valves will not create a possibility for an accident of a new or different type than those previously evaluated.

3. Does the proposed Technical Specification change involve a significant reduction in a margin of safety?

Response: No The proposed deletion of the requirement to maintain an automatic transfer capability for the power supply to the LPCI inboard injection valves, RHR minimum flow valves and recirculation pump discharge valves does not change the conditions, operating configurations, or minimum amount of operating equipment credited in the safety analyses for accident or transient mitigation. The proposed change does not alter the assumptions contained in the safety analyses. The proposed change does not alter the manner in which safety limits, limiting safety system settings or limiting conditions for operation are determined. The proposed change does not impact the safety analysis-credited redundancy or availability of SSCs required for accident or transient mitigation, or the ability of the plant to cope with design basis events as assumed in safety analyses. In addition, no changes are proposed in the manner in which the credited SSCs provide plant protection or which create new modes of plant operation. The requirements of 10 CFR 50.46 and Appendix K continue to be met. Therefore, the proposed change does not involve a significant reduction in the margin of safety.

Based on the above, TVA concludes that the proposed TS changes present no significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of "no significant hazards consideration" is justified.

E-20

4.4 Conclusions In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the TS changes will not be inimical to the common defense and security or the health and safety of the public.

5.0 ENVIRONMENTAL CONSIDERATION

A review has determined that the proposed TS changes would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or would change an inspection or surveillance requirement. However, the proposed TS changes do not involve: (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluent that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure.

Accordingly, the proposed TS changes meet the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed TS changes.

6.0 REFERENCES

1. ANP-2908(P) Revision 0, "Browns Ferry Units 1, 2, and 3 105% OLTP LOCA Break Spectrum Analysis," AREVA NP Inc., dated March 2010.

2. Letter from M. H. Chernoff (NRC) to K. Singer (TVA), "Browns Ferry Nuclear Plant, Unit 1 - Issuance of an Amendment Regarding Deletion of the Low Pressure Coolant Injection Motor-Generator Sets (TAC No. MC3822)(TS-427)," dated June 20, 2005.

3. Letter from T. E. Abney (TVA) to NRC, "Browns Ferry Nuclear Plant (BFN) - Units 1, 2 and 3 - Adoption of the General Electric (GE) SAFER/GESTR Loss of Coolant Accident Methodology," dated March 11, 1997.

4. Letter from T. E. Abney (TVA) to NRC, "Browns Ferry Nuclear Plant (BFN) - Units 2 and 3 - Revision to Technical Specification (TS) Bases (TS-389)," dated April 24, 1997.

5. Letter from J. F. Williams (TVA) to O.D. Kingsley (TVA), "Browns Ferry Nuclear Plant Units 1, 2 and 3 - Revision to Technical Specification Bases (TAC Nos. M9791 1, M97912, M97913, M98695 and M98696) (TS 388 and TS 389)," dated July 8, 1997.

6. ANP-2910(P) Revision 0, "Browns Ferry Units 1, 2, and 3 105% OLTP LOCA-ECCS Analysis MAPLHGR Limit for ATRIUM TM-10 Fuel," AREVA NP Inc., dated March 2010.

7. Letter from R. M. Krich (TVA) to NRC, "Final Report of Emergency Core Cooling System Evaluation Model Changes," dated April 30, 2010.

E-21

EVALUATION FOR TECHNICAL SPECIFICATION CHANGE TS-429 Deletion of Low Pressure Coolant Injection Motor-Generator Sets for Browns Ferry Nuclear Plant, Units 2 and 3 ATTACHMENT I Proposed Technical Specifications and Bases Page Markups for BFN, Unit 2 Technical Specifications Paaes: 3.5-7 Technical Specifications Bases Pages: B 3.5-3, B 3.5-21, B 3.8-86, B 3.8-87a, B 3.8-93

ECCS - Operating 3.5.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.5.1.10 ------------------- NOTE -------------

Valve actuation may be excluded.

Verify the ADS actuates on an actual or 24 months simulated automatic initiation signal.

SR 3.5.1.11 ------------------- NOTE -------------

Not required to be performed until 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after reactor steam pressure and flow are adequate to perform the test.

Verify each ADS valve opens when manually 24 months actuated.

SR 3.6.1.2 Verify autematic transfcr of the power supply 24 months fr*om1 theR nal zourcc to the altcrnat Sourcc for cach LPG! subsystem inboard 0njcctien valve and each rccirclation pump disehaFge valve.

BFN-UNIT 2 3.5-7 Amendment No. 265 N,,embc, 30, 1998

ECCS - Operating B 3.5.1 BASES BACKGROUND at 0.2 seconds when offsite power is available and B, C, and D (continued) pumps approximately 7, 14, and 21 seconds afterwards and if offsite power is not available all pumps 7 seconds after diesel generator power is available). When the RPV pressure drops sufficiently, CS System flow to the RPV begins. A full flow test line is provided to route water from and to the suppression pool to allow testing of the CS System without spraying water in the RPV.

LPCI is an independent operating mode of the RHR System.

There are two LPCI subsystems (Ref. 2), each consisting of two motor driven pumps and piping and valves to transfer water from the suppression pool to the RPV via the corresponding recirculation loop.

The two LPCI pumps and associated motor operated valves in each LPCI subsystem are powered from separate 4 kV shutdown boards. Both pumps in a LPCI subsystem inject water into the reactor vessel through a common inboard injection valve and depend on the closure of the recirculation pump discharge valve following a LPCI injection signal.

Therefore, each LPCI subsystem's common inboard injection valve and recirculation pump discharge valve are powered from one of the two 4 kV shutdown boards associated with that subsystem. The abilit' to p.OVidc p.wc. to the inboard injo.ti'n valvc and the rccirUlation pump dischargc valye fromf tMo independent 4 k(V shutdown beards cnzUrcz that a single failure of a diesel goncrator (DG) will not result inthe failurc of bot

[*Cn ne n.

(continued)

BFN-UNIT 2 B 3.5-3 Revision . March 22, 20*G7

ECCS - Operating B 3.5.1 BASES SURVEILLANCE SR 3.5.1.11 (continued)

REQUIREMENTS The Frequency of 24 months is based on the need to perform the Surveillance under the conditions that apply just prior to or during a startup from a plant outage. Operating experience with these components supports performance of the Surveillance at the 24 month Frequency, which is based on the refueling cycle.

Therefore, the Frequency was concluded to be acceptable from a reliability standpoint.

SR 3.611A2 Verifieation evcr', 24 moenths of the autematce transfcr capablity between thcEF ormal and altrnfatc poewr nupplYh(480 V shutdown bo~ards) for thc RMOV boards which supply pewc for cach LPG! subsystem inboard injcctien valve and cach rccircUlatien pump dischargc Yalyc dcmoneStratcs that ACG clcctrical powcr is ayailablc to epcrate these valves following loss of powcr to onc of the 4 WV shutdown boadrds. The abiliy to provide power to the inboard injcction valve and the rccircUlation pump dischargc valve frmto needet4k shutdown boards cnSUrcs that single failurc of an EIDO willno T-hcrcforc, the fai!urc of the autonm-aticn trannsfcr capability woI rcsult in the f the affcctod LPC!I enprblt Iuyto. The 24 month Frcqucncy has been found to be acceptablc base cngccong judgment and epcrating cxpcricncc.

on (continued)

Revisbe4-ion BFN-UNIT 2 B 3.5-21 No~lvemer3,+I1998/*-

Distribution Systems - Operating B 3.8.7 BASES (continued)

LCO The required electrical power distribution subsystems listed in Table B 3.8.7-1 ensure the availability of AC and DC electrical power for the systems required to shut down the reactor and maintain it in a safe condition after an abnormal operational transient or a postulated DBA. The AC and DC electrical power distribution subsystems are required to be OPERABLE.

Maintaining the AC and DC electrical power distribution subsystems OPERABLE ensures that the redundancy incorporated into the design of ESF is not defeated. Therefore, a single failure within any system or within the electrical power distribution subsystems will not prevent safe shutdown of the reactor.

The AC electrical power distribution subsystems require the associated buses and electrical circuits to be energized to their proper voltages. in addition, for the D Or E RMOV Boards to be OPERABLE, they must be able to auto transfer on loss et voltage. This feature enU,rs that the fa'Iur1 ef ene Diesel Gencrator Will not result in the loss of an RHR subsystcm.

OPERABLE DC electrical power distribution subsystems require the associated buses to be energized to their proper voltage from either the associated battery or charger.

Based on the number of safety significant electrical loads associated with each board listed in Table B 3.8.7-1, if one or more of the boards becomes inoperable, entry into the appropriate ACTIONS of LCO 3.8.7 is required. Other boards, such as motor control centers (MCC) and distribution panels which help comprise the AC and DC distribution systems may not be listed in Table B 3.8.7-1. The loss of electrical loads associated with these boards may not result in a complete loss of a redundant safety function necessary to shut down the reactor and maintain it in a safe condition. Therefore, should (continued)

BFN-UNIT 2 B 3.8-86 Revision 0

Distribution Systems - Operating B 3.8.7 BASES LCO When 480 V Shutdown Board 2B is aligned to the alternate (continued) supply 4.16 kV Shutdown Board C, a LOCA/LOOP with a failure of the Shutdown Board D Battery would disable the normal supply 4.16 kV Shutdown Board D, and would also prevent the 480 V Shutdown Board 2B from load shedding its 480 V loads which would overload the alternate supply Diesel Generator D.

This would result in the loss of diesel generators C and D, associated 4.16 kV shutdown boards and RHRSW pumps.

Therefore, the restrictions on the associated drawings shall be adhered to whenever 480 V Shutdown Board 2B is on its alternate supply. -2A, 2B,Dand2E The Unit 2 480 V RMOV boards 2A and 213 have an alternate power supply from the other 480 V shutdown board. Interlocks prevent paralleling normal and alternate feeder breakers. The boards are considered inoperable when powered from their alternate feeder breakers because a single failure of the power source would affect both divisions.

The Unit 2 250 V DC RMOV boards 2A, 2B, and 2C have alternate power supplies from another 250 V Unit DC board.

Interlocks prevent paralleling normal and alternate feeder breakers. The boards are considered inoperable when powered from their alternate feeder breakers because a single failure of the power source could affect both divisions depending on the board alignment.

If a 4.16 kV or 480 V shutdown board is aligned to its alternate 250 V DC control power source a single failure of the alternate power source could affect both ECCS divisions and common equipment needed to support the other units depending on the board alignment. Therefore, the restrictions on the associated drawings shall be adhered to whenever a 4.16 kV or 480 V shutdown board is on its alternate control power supply.

(continued)

BFN-UNIT 2 B 3.8-87a Revision 39, 56 APFiOI 3, 2OO

Distribution Systems - Operating B 3.8.7 BASES ACTIONS B.1 (continued)

Pursuant to LCO 3.0.6, the Distribution System Action C would not be entered even if the 480 V shutdown board was inoperable, resulting in de-energization of a 480 V RMOV board. Therefore, the Required Actions of Condition B are modified by a Note to indicate that when Condition B is entered with no power source to 480 V RMOV board 2D or 2E, Action C must be immediately entered. This allows Condition B to provide requirements for the loss of the 480 V shutdown board without regard to whether 480 V RMOV board 2D or 2E is de-energized. Action C provides the appropriate restrictions for a de-energized 480 V RMOV board 2D or 2E.

C.1 480 V RMOV board 2D or 2E is inopcrablc if the automati transfer capability between the no~rmal and alternlate powo supply (LPC! MG sets) is inepr-ablc for any reason. (Rf,  ;

also to bascs for SR 3.6.1.12.)

With 480 V RMOV Board D or E inoperable, the respective RHR subsystem supported by each affected board is inoperable for LPCI. The overall reliability is reduced because of the loss of one LPCI/RHR subsystem. In this condition, the remaining OPERABLE ECCS subsystems provide adequate core cooling during a LOCA. However, overall ECCS reliability is reduced, because a single failure in one of the remaining OPERABLE subsystems, concurrent with a LOCA, may result in the ECCS not being able to perform its intended safety function.

Therefore, the associated RHR subsystem must be declared inoperable immediately, and the actions in the appropriate system specification taken.

(continued)

BFN-UNIT 2 B 3.8-93 Revision 0

EVALUATION FOR TECHNICAL SPECIFICATION CHANGE TS-429 Deletion of Low Pressure Coolant Injection Motor-Generator Sets for Browns Ferry Nuclear Plant, Units 2 and 3 ATTACHMENT 2 Proposed Technical Specifications and Bases Page Markups for BFN, Unit 3 Technical Specifications Pages: 3.5-7 Technical Specifications Bases Pages: B 3.5-3, B 3.5-21, B 3.8-86, B 3.8-88, B 3.8-94

ECCS - Operating 3.5.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.5.1.10 ------------------- NOTE -------------

Valve actuation may be excluded.

Verify the ADS actuates on an actual or 24 months simulated automatic initiation signal.

SR 3.5.1.11 ------------------- NOTE -------------

Not required to be performed until 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after reactor steam pressure and flow are adequate to perform the test.

Verify each ADS valve opens when manually 24 months actuated.

SR 3.5.1.2 Verify automnatic transfcr of the power supply 24 menths fromn the noFrmal GoUrcc to the alternate Source for each LPG! subsystem *nboard 0njectien valve and each recirulation pump diehPl vale . i BFN-UNIT 3 3.5-7 Amendment No. 2-16 No)venmber 30, 1998

ECCS - Operating B 3.5.1 BASES BACKGROUND at 0.2 seconds when offsite power is available and B, C, and D (continued) pumps approximately 7, 14, and 21 seconds afterwards and if offsite power is not available all pumps 7 seconds after diesel generator power is available). When the RPV pressure drops sufficiently, CS System flow to the RPV begins. A full flow test line is provided to route water from and to the suppression pool to allow testing of the CS System without spraying water in the RPV.

LPCI is an independent operating mode of the RHR System.

There are two LPCI subsystems (Ref. 2), each consisting of two motor driven pumps and piping and valves to transfer water from the suppression pool to the RPV via the corresponding recirculation loop.

The two LPCI pumps and associated motor operated valves in each LPCI subsystem are powered from separate 4 kV shutdown boards. Both pumps in a LPCI subsystem inject water into the reactor vessel through a common inboard injection valve and depend on the closure of the recirculation pump discharge valve following a LPCI injection signal.

Therefore, each LPCI subsystem's common inboard injection valve and recirculation pump discharge valve are powered from one of the two 4 kV shutdown boards associated with that subsystem. The ability to p.o.idc pow.. to the inboead i -j,,i valv'e and the FecIrcUlaioun pumFp diseharyu valve iruir; MW thlnt n sinnir B II 9nrcIncnrdhnt A k" Qh-WIMAn hmmirtV ionq'.irir v,..*.*

tniiii

.*.,*.v of a dIc-nl gnc*r-ator (DG) will not rczult in the taIIurc eT betfl LPG! pumps in one subsystem.

(continued)

BFN-UNIT 3 B 3.5-3 Revision 0T67 APFrI - 0,2008

ECCS - Operating B 3.5.1 BASES SURVEILLANCE SR 3.5.1.11 (continued)

REQUIREMENTS The Frequency of 24 months is based on the need to perform the Surveillance under the conditions that apply just prior to or during a startup from a plant outage. Operating experience with these components supports performance of the Surveillance at the 24 month Frequency, which is based on the refueling cycle.

Therefore, the Frequency was concluded to be acceptable from a reliability standpoint.

8 R 3..1.2 Verification every 21 moenths of the autematce transfcr capab~iiy I between the nrmFFal and altcrnatc power SUPPly (480 V shutdown boards) for the RMOV boards which supply powrfo cach LPG' subsystem inboardinjcctien valve and cach rccirculation pum~p dischargc valve dcmans~trates that AC electrisa! poc fsaalable to epcrate Ithcsc valWcs following l*ss of p.we,, to oc of thc I .,shutwn br..-,.ds. The ability to proVidc pewcr to the inboard inijcctien valve and the rccirulatien pump disesharge valve from twe independent 4 k shutdown boarlds e-nWrcs that sing-l famIlue of an ED-I will not result in the fa;Iuro of both LPGI pum-n one subsystem.

T-hccfoFc, the faiurce of the autoemati transfcr capability Will rcsult in the inopcrability of the affccted L=PCI subsystem. The 24 month Frequency has been found to be acceptable base engneeing judgment and operating experience.

on (continued)

BFN-UNIT 3 B 3.5-21 Amend vsnt No. 2 Neoember 30, 1998

Distribution Systems - Operating B 3.8.7 BASES (continued)

LCO The required electrical power distribution subsystems listed in Table B 3.8.7-1 ensure the availability of AC and DC electrical power for the systems required to shut down the reactor and maintain it in a safe condition after an abnormal operational transient or a postulated DBA. The AC and DC electrical power distribution subsystems are required to be OPERABLE.

Maintaining the AC and DC electrical power distribution subsystems OPERABLE ensures that the redundancy incorporated into the design of ESF is not defeated. Therefore, a single failure within any system or within the electrical power distribution subsystems will not prevent safe shutdown of the reactor.

The AC electrical power distribution subsystems require the associated buses and electrical circuits to be energized to their proper voltages. in additi.n, for the D Or E RIVIOV Boards to be OPERABLE, they must be able to auto *n transfeF loss of voltagc. This feature enSUres that the failure of onc Diesel Gencrator Will net rssult in the loss of an RHR subsystem.

OPERABLE DC electrical power distribution subsystems require the associated buses to be energized to their proper voltage from either the associated battery or charger.

Based on the number of safety significant electrical loads associated with each board listed in Table B 3.8.7-1, if one or more of the boards becomes inoperable, entry into the appropriate ACTIONS of LCO 3.8.7 is required. Other boards, such as motor control centers (MCC) and distribution panels which help comprise the AC and DC distribution systems may not be listed in Table B 3.8.7-1. The loss of electrical loads associated with these boards may not result in a complete loss of a redundant safety function necessary to shut down the reactor and maintain it in a safe condition. Therefore, should (continued)

BFN-UNIT 3 B 3.8-86 Revision G

Distribution Systems - Operating B 3.8.7 BASES LCO generators 3A and 3C, associated 4.16 kV shutdown boards, (continued) and RHRSW pumps. Therefore, the restrictions on the associated drawings shall be adhered to whenever 480 V Shutdown Board 3A is on its alternate supply.

The Unit 3 diesel auxiliary boards have an alternate power supply from the other 480 V shutdown board. Interlocks prevent paralleling normal and alternate feeder breakers. The boards are considered inoperable when powered from their alternate feeder breakers because a single failure of the power source would affect both divisions. 3A, 3B, 3D and 3E The Unit 3 480 V RMOV boards 3A eand 33 have an alternate power supply from the other 480 V shutdown board. Interlocks prevent paralleling normal and alternate feeder breakers. The boards are considered inoperable when powered from their alternate feeder breakers because a single failure of the power source would affect both divisions.

The Unit 3 250 V DC RMOV boards 3A, 3B, and 3C have alternate power supplies from another 250 V Unit DC board.

Interlocks prevent paralleling normal and alternate feeder breakers. The boards are considered inoperable when powered from their alternate feeder breakers because a single failure of the power source could affect both divisions depending on the board alignment.

If a 4.16 kV or 480 V shutdown board is aligned to its alternate 250 V DC control power source a single failure of the alternate power source could affect both ECCS divisions and common equipment needed to support the other units depending on the board alignment. Therefore, the restrictions on the associated drawings shall be adhered to whenever a 4.16 kV or 480 V shutdown board is on its alternate control power supply.

(continued)

BFN-UNIT 3 B 3.8-88 Revision 0 ApF" 03, ,2No

Distribution Systems - Operating B 3.8.7 BASES ACTIONS B.1 (continued)

Pursuant to LCO 3.0.6, the Distribution System Action C would not be entered even if the 480 V shutdown board was inoperable, resulting in de-energization of a 480 V RMOV board. Therefore, the Required Actions of Condition B are modified by a Note to indicate that when Condition B is entered with no power source to 480 V RMOV board 3D or 3E, Action C must be immediately entered. This allows Condition B to provide requirements for the loss of the 480 V shutdown board without regard to whether 480 V RMOV board 3D or 3E is de-energized. Action C provides the appropriate restrictions for a de-energized 480 V RMOV board 3D or 3E.

C.1 480 V RMOV board 3D) or 3E ic inopcrablc if the automati transfcr capability between the normal and altcrnate powc supply (LPC! MG sets) is inepcrable for any rcasen. (Refc also to bases for SR 3.6.1.12.)

With 480 V RMOV Board D or E inoperable, the respective RHR subsystem supported by each affected board is inoperable for LPCI. The overall reliability is reduced because of the loss of one LPCI/RHR subsystem. In this condition, the remaining OPERABLE ECCS subsystems provide adequate core cooling during a LOCA. However, overall ECCS reliability is reduced, because a single failure in one of the remaining OPERABLE subsystems, concurrent with a LOCA, may result in the ECCS not being able to perform its intended safety function.

Therefore, the associated RHR subsystem must be declared inoperable immediately, and the actions in the appropriate system specification taken.

(continued)

BFN-UNIT 3 B 3.8-94 Revision 0

EVALUATION FOR TECHNICAL SPECIFICATION CHANGE TS-429 Deletion of Low Pressure Coolant Injection Motor-Generator Sets for Browns Ferry Nuclear Plant, Units 2 and 3 ATTACHMENT 3 Retyped Proposed Technical Specifications and Bases Pages for BFN, Unit 2 Technical Specifications Pages: 3.5-7 Technical Specifications Bases Pages: B 3.5-3, B 3.5-21, B 3.8-86, B 3.8-87a, B 3.8-93

ECCS - Operating 3.5.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.5.1.10 ------------------- NOTE -------------

Valve actuation may be excluded.

Verify the ADS actuates on an actual or 24 months simulated automatic initiation signal.

SR 3.5.1.11 ------------------- NOTE -------------

Not required to be performed until 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after reactor steam pressure and flow are adequate to perform the test.

Verify each ADS valve opens when manually 24 months actuated.

SR 3.5.1.12 (Deleted)

BFN-UNIT 2 3.5-7 Amendment No. I

ECCS - Operating B 3.5.1 BASES BACKGROUND at 0.2 seconds when offsite power is available and B, C, and D (continued) pumps approximately 7, 14, and 21 seconds afterwards and if offsite power is not available all pumps 7 seconds after diesel generator power is available). When the RPV pressure drops sufficiently, CS System flow to the RPV begins. A full flow test line is provided to route water from and to the suppression pool to allow testing of the CS System without spraying water in the RPV.

LPCI is an independent operating mode of the RHR System.

There are two LPCI subsystems (Ref. 2), each consisting of two motor driven pumps and piping and valves to transfer water from the suppression pool to the RPV via the corresponding recirculation loop.

The two LPCI pumps and associated motor operated valves in each LPCI subsystem are powered from separate 4 kV shutdown boards. Both pumps in a LPCI subsystem inject water into the reactor vessel through a common inboard injection valve and depend on the closure of the recirculation pump discharge valve following a LPCI injection signal.

Therefore, each LPCI subsystem's common inboard injection valve and recirculation pump discharge valve are powered from one of the two 4 kV shutdown boards associated with that subsystem.

(continued)

BFN-UNIT 2 B 3.5-3 Revision I

ECCS - Operating B 3.5.1 BASES SURVEILLANCE SR 3.5.1.11 (continued)

REQUIREMENTS The Frequency of 24 months is based on the need to perform the Surveillance under the conditions that apply just prior to or during a startup from a plant outage. Operating experience with these components supports performance of the Surveillance at the 24 month Frequency, which is based on the refueling cycle.

Therefore, the Frequency was concluded to be acceptable from a reliability standpoint.

(continued)

BFN-UNIT 2 B 3.5-21 Revision I

Distribution Systems - Operating B 3.8.7 BASES (continued)

LCO The required electrical power distribution subsystems listed in Table B 3.8.7-1 ensure the availability of AC and DC electrical power for the systems required to shut down the reactor and maintain it in a safe condition after an abnormal operational transient or a postulated DBA. The AC and DC electrical power distribution subsystems are required to be OPERABLE.

Maintaining the AC and DC electrical power distribution subsystems OPERABLE ensures that the redundancy incorporated into the design of ESF is not defeated. Therefore, a single failure within any system or within the electrical power distribution subsystems will not prevent safe shutdown of the reactor.

The AC electrical power distribution subsystems require the associated buses and electrical circuits to be energized to their proper voltages. OPERABLE DC electrical power distribution subsystems require the associated buses to be energized to their proper voltage from either the associated battery or charger.

Based on the number of safety significant electrical loads associated with each board listed in Table B 3.8.7-1, if one or more of the boards becomes inoperable, entry into the appropriate ACTIONS of LCO 3.8.7 is required. Other boards, such as motor control centers (MCC) and distribution panels which help comprise the AC and DC distribution systems may not be listed in Table B 3.8.7-1. The loss of electrical loads associated with these boards may not result in a complete loss of a redundant safety function necessary to shut down the reactor and maintain it in a safe condition. Therefore, should (continued)

BFN-UNIT 2 B 3.8-86 Revision

Distribution Systems - Operating B 3.8.7 BASES LCO When 480 V Shutdown Board 2B is aligned to the alternate (continued) supply 4.16 kV Shutdown Board C, a LOCA/LOOP with a failure of the Shutdown Board D Battery would disable the normal supply 4.16 kV Shutdown Board D, and would also prevent the 480 V Shutdown Board 2B from load shedding its 480 V loads which would overload the alternate supply Diesel Generator D.

This would result in the loss of diesel generators C and D, associated 4.16 kV shutdown boards and RHRSW pumps.

Therefore, the restrictions on the associated drawings shall be adhered to whenever 480 V Shutdown Board 2B is on its alternate supply.

The Unit 2 480 V RMOV boards 2A, 2B, 2D and 2E have an alternate power supply from the other 480 V shutdown board.

Interlocks prevent paralleling normal and alternate feeder breakers. The boards are considered inoperable when powered from their alternate feeder breakers because a single failure of the power source would affect both divisions.

The Unit 2 250 V DC RMOV boards 2A, 2B, and 2C have alternate power supplies from another 250 V Unit DC board.

Interlocks prevent paralleling normal and alternate feeder breakers. The boards are considered inoperable when powered from their alternate feeder breakers because a single failure of the power source could affect both divisions depending on the board alignment.

If a 4.16 kV or 480 V shutdown board is aligned to its alternate 250 V DC control power source a single failure of the alternate power source could affect both ECCS divisions and common equipment needed to support the other units depending on the board alignment. Therefore, the restrictions on the associated drawings shall be adhered to whenever a 4.16 kV or 480 V shutdown board is on its alternate control power supply.

(continued)

BFN-UNIT 2 B 3.8-87a Revision I

Distribution Systems - Operating B 3.8.7 BASES ACTIONS B.1 (continued)

Pursuant to LCO 3.0.6, the Distribution System Action C would not be entered even if the 480 V shutdown board was inoperable, resulting in de-energization of a 480 V RMOV board.

Therefore, the Required Actions of Condition B are modified by a Note to indicate that when Condition B is entered with no power source to 480 V RMOV board 2D or 2E, Action C must be immediately entered. This allows Condition B to provide requirements for the loss of the 480 V shutdown board without regard to whether 480 V RMOV board 2D or 2E is de-energized.

Action C provides the appropriate restrictions for a de-energized 480 V RMOV board 2D or 2E.

C._1 With 480 V RMOV Board D or E inoperable, the respective RHR subsystem supported by each affected board is inoperable for LPCI. The overall reliability is reduced because of the loss of one LPCI/RHR subsystem. In this condition, the remaining OPERABLE ECCS subsystems provide adequate core cooling during a LOCA. However, overall ECCS reliability is reduced, because a single failure in one of the remaining OPERABLE subsystems, concurrent with a LOCA, may result in the ECCS not being able to perform its intended safety function.

Therefore, the associated RHR subsystem must be declared inoperable immediately, and the actions in the appropriate system specification taken.

(continued)

BFN-UNIT 2 B 3.8-93 Revision I

EVALUATION FOR TECHNICAL SPECIFICATION CHANGE TS-429 Deletion of Low Pressure Coolant Injection Motor-Generator Sets for Browns Ferry Nuclear Plant, Units 2 and 3 ATTACHMENT 4 Retyped Proposed Technical Specifications and Bases Pages for BFN, Unit 3.

Technical Specifications Pages: 3.5-7 Technical Specifications Bases Pages: B 3.5-3, B 3.5-21, B 3.8-86, B 3.8-88, B 3.8-94

ECCS - Operating 3.5.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.5.1.10 ------------------- NOTE -------------

Valve actuation may be excluded.

Verify the ADS actuates on an actual or 24 months simulated automatic initiation signal.

SR 3.5.1.11 ------------------- NOTE -------------

Not required to be performed until 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after reactor steam pressure and flow are adequate to perform the test.

Verify each ADS valve opens when manually 24 months actuated.

SR 3.5.1.12 (Deleted)

BFN-UNIT 3 3.5-7 Amendment No. I

ECCS - Operating B 3.5.1 BASES BACKGROUND at 0.2 seconds when offsite power is available and B, C, and D (continued) pumps approximately 7, 14, and 21 seconds afterwards and if offsite power is not available all pumps 7 seconds after diesel generator power is available). When the RPV pressure drops sufficiently, CS System flow to the RPV begins. A full flow test line is provided to route water from and to the suppression pool to allow testing of the CS System without spraying water in the RPV.

LPCI is an independent operating mode of the RHR System.

There are two LPCI subsystems (Ref. 2), each consisting of two motor driven pumps and piping and valves to transfer water from the suppression pool to the RPV via the corresponding recirculation loop.

The two LPCI pumps and associated motor operated valves in each LPCI subsystem are powered from separate 4 kV shutdown boards. Both pumps in a LPCI subsystem inject water into the reactor vessel through a common inboard injection valve and depend on the closure of the recirculation pump discharge valve following a LPCI injection signal.

Therefore, each LPCI subsystem's common inboard injection valve and recirculation pump discharge valve are powered from one of the two 4 kV shutdown boards associated with that subsystem.

I (continued)

BFN-UNIT 3 B 3.5-3 Revision

ECCS - Operating B 3.5.1 BASES SURVEILLANCE SR 3.5.1.11 (continued)

REQUIREMENTS The Frequency of 24 months is based on the need to perform the Surveillance under the conditions that apply just prior to or during a startup from a plant outage. Operating experience with these components supports performance of the Surveillance at the 24 month Frequency, which is based on the refueling cycle.

Therefore, the Frequency was concluded to be acceptable from a reliability standpoint.

(continued)

BFN-UNIT 3 B 3.5-21 Revision I

Distribution Systems - Operating B 3.8.7 BASES (continued)

LCO The required electrical power distribution subsystems listed in Table B 3.8.7-1 ensure the availability of AC and DC electrical power for the systems required to shut down the reactor and maintain it in a safe condition after an abnormal operational transient or a postulated DBA. The AC and DC electrical power distribution subsystems are required to be OPERABLE.

Maintaining the AC and DC electrical power distribution subsystems OPERABLE ensures that the redundancy incorporated into the design of ESF is not defeated. Therefore, a single failure within any system or within the electrical power distribution subsystems will not prevent safe shutdown of the reactor.

The AC electrical power distribution subsystems require the associated buses and electrical circuits to be energized to their proper voltages. OPERABLE DC electrical power distribution subsystems require the associated buses to be energized to their proper voltage from either the associated battery or charger.

Based on the number of safety significant electrical loads associated with each board listed in Table B 3.8.7-1, if one or more of the boards becomes inoperable, entry into the appropriate ACTIONS of LCO 3.8.7 is required. Other boards, such as motor control centers (MCC) and distribution panels which help comprise the AC and DC distribution systems may not be listed in Table B 3.8.7-1. The loss of electrical loads associated with these boards may not result in a complete loss of a redundant safety function necessary to shut down the reactor and maintain it in a safe condition. Therefore, should (continued)

BFN-UNIT 3 B 3.8-86 Revision

Distribution Systems - Operating B 3.8.7 BASES LCO generators 3A and 3C, associated 4.16 kV shutdown boards, (continued) and RHRSW pumps. Therefore, the restrictions on the associated drawings shall be adhered to whenever 480 V Shutdown Board 3A is on its alternate supply.

The Unit 3 diesel auxiliary boards have an alternate power supply from the other 480 V shutdown board. Interlocks prevent paralleling normal and alternate feeder breakers. The boards are considered inoperable when powered from their alternate feeder breakers because a single failure of the power source would affect both divisions.

The Unit 3 480 V RMOV boards 3A, 3B, 3D and 3E have an alternate power supply from the other 480 V shutdown board.

Interlocks prevent paralleling normal and alternate feeder breakers. The boards are considered inoperable when powered from their alternate feeder breakers because a single failure of the power source would affect both divisions.

The Unit 3 250 V DC RMOV boards 3A, 3B, and 3C have alternate power supplies from another 250 V Unit DC board.

Interlocks prevent paralleling normal and alternate feeder breakers. The boards are considered inoperable when powered from their alternate feeder breakers because a single failure of the power source could affect both divisions depending on the board alignment.

If a 4.16 kV or 480 V shutdown board is aligned to its alternate 250 V DC control power source a single failure of the alternate power source could affect both ECCS divisions and common equipment needed to support the other units depending on the board alignment. Therefore, the restrictions on the associated drawings shall be adhered to whenever a 4.16 kV or 480 V shutdown board is on its alternate control power supply.

(continued)

BFN-UNIT 3 B 3.8-88 Revision I

Distribution Systems - Operating B 3.8.7 BASES ACTIONS B.1 (continued)

Pursuant to LCO 3.0.6, the Distribution System Action C would not be entered even if the 480 V shutdown board was inoperable, resulting in de-energization of a 480 V RMOV board.

Therefore, the Required Actions of Condition B are modified by a Note to indicate that when Condition B is entered with no power source to 480 V RMOV board 3D or 3E, Action C must be immediately entered. This allows Condition B to provide requirements for the loss of the 480 V shutdown board without regard to whether 480 V RMOV board 3D or 3E is de-energized.

Action C provides the appropriate restrictions for a de-energized 480 V RMOV board 3D or 3E.

C.1 With 480 V RMOV Board D or E inoperable, the respective RHR subsystem supported by each affected board is inoperable for LPCI. The overall reliability is reduced because of the loss of one LPCI/RHR subsystem. In this condition, the remaining OPERABLE ECCS subsystems provide adequate core cooling during a LOCA. However, overall ECCS reliability is reduced, because a single failure in one of the remaining OPERABLE subsystems, concurrent with a LOCA, may result in the ECCS not being able to perform its intended safety function.

Therefore, the associated RHR subsystem must be declared inoperable immediately, and the actions in the appropriate system specification taken.

(continued)

BFN-UNIT 3 B 3.8-94 Revision