Text

Supplement to Technical Specifications Change TS-474-Request to Add a TS 3.7.3, Control Room Emergency Ventilation (Crev) System, Action to Address Two Crev Subsystems Inoperable Due to
	ML12017A161
Person / Time
Site:	Browns Ferry
Issue date:	01/13/2012
From:	James Shea; Tennessee Valley Authority
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	Download: ML12017A161 (119)
	v • d • e

Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402 January 13, 2012 10 CFR 50.4 10 CFR 50.90 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Browns Ferry Nuclear Plant (BFN), Units 1, 2, and 3 Facility Operating License Nos. DPR-33, DPR-52, and DPR-68 NRC Docket Nos. 50-259, 50-260, and 50-296

Subject:

Supplement to Technical Specifications Change TS-474 - Request to Add a TS 3.7.3, "Control Room Emergency Ventilation (CREV) System," Action to Address Two CREV Subsystems Inoperable Due to Inoperable CREV System High Efficiency Particulate Air (HEPA) Filter and/or Charcoal Adsorbers

References:

1. Letter from TVA to NRC, Technical Specifications Change TS-474 -

Request to Add a TS 3.7.3, "Control Room Emergency Ventilation (CREV)

System," Action to Address Two CREV Subsystems Inoperable Due to Inoperable CREV System High Efficiency Particulate Air (HEPA) Filter and/or Charcoal Adsorbers," dated August 27, 2010

2. NRC Letter to TVA, "Browns Ferry Nuclear Plant, Units 1, 2, and 3 -

Request for Additional Information Regarding Technical Specification Change TS-474 (TAC Nos. ME4668, ME4669, and ME4670)," dated March 10, 2011

3. Letter from TVA to NRC, "Response to Request for Additional Information regarding Technical Specifications Change TS-474 - TS 3.7.3, Control Room Emergency Ventilation (CREV) System," dated April 11, 2011

4. Letter from TVA to NRC, "Schedule for Supplement to Technical Specification Change TS-474," dated December 21, 2011 D00Q3.

U.S. Nuclear Regulatory Commission Page 2 January 13, 2012 By letter dated August 27, 2010 (Reference 1), the Tennessee Valley Authority (TVA) submitted a License Amendment Request to revise Technical Specification (TS) 3.7.3, Control Room Emergency Ventilation (CREV) System. In this request, TVA proposed to provide a completion time of 90 days to restore the CREV System HEPA filter and charcoal adsorbers to operable status.

On March 10, 2011, the NRC requested TVA provide additional information in order to support their review of the proposed change to the TS (Reference 2). By letter dated April 11, 2011 (Reference 3),

TVA provided the response to the NRC request for additional information.

During a July 26, 2011, teleconference between NRC and TVA representatives, TVA agreed to supplement the License Amendment Request to revise the proposed completion time from 90 days for restoration of inoperable HEPA filters and charcoal adsorbers to 7 days to restore an inoperable HEPA filter and 14 days to restore an inoperable charcoal adsorber provided the flowrate requirements of the Ventilation Filter Testing Program are maintained. By letter dated December 21, 2011 (Reference 4),

TVA agreed to provide this supplement by January 13, 2012. The enclosure to this letter provides the supplement in the form of revised proposed TS and Bases pages. Attachments 1 through 4 of this enclosure replace in their entirety Attachments 1 through 4 of the enclosure to the Reference 1 letter.

TVA has determined that the supplemental information provided by this letter does not affect the no significant hazards considerations associated with the proposed TS changes provided in the Reference 1 letter. The proposed TS changes still qualify for a 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),

TVA is sending a copy of this letter and the enclosures to the Alabama Department of Public Health.

There are no new regulatory commitments in this submittal.

Please direct any questions concerning this matter to Tom Hess at (423) 751-3487.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 13th day of January 2012.

Res

tfully, S

Shea anager, Corporate Nuclear Licensing

U.S. Nuclear Regulatory Commission Page 3 January 13, 2012

Enclosure:

Browns Ferry Nuclear Plant (BFN), Units 1, 2, and 3, Supplement to Technical Specifications (TS) Change 474 cc (Enclosure):

NRC Regional Administrator-Region II NRC Senior Resident Inspector - Browns Ferry Nuclear Plant State Health Officer, Alabama State Department of Public Health

U.S. Nuclear Regulatory Commission Page 4 January 13, 2012 bcc (Enclosure)

NRC Project Manager - Browns Ferry Nuclear Plant NRC Branch Chief - Region II EDMS bcc (w/o Enclosure):

K. W. Brown M. J. Durr J. E. Emens C. J. Gannon T, A. Hess D. E. Jernigan L. A. Jones H. Lee M. W. Oliver K. J. Poison P. B. Summers P, D. Swafford E. J. Vigluicci NSRB

ENCLOSURE Browns Ferry Nuclear Plant (BFN), Units 1, 2, and 3 Supplement to Technical Specifications (TS) Change 474 License Amendment Request to Add a TS 3.7.3, "Control Room Emergency Ventilation (CREV) System," Action to Address Inoperable CREV High Efficiency Particulate Air (HEPA) Filter and/or Charcoal Adsorbers Browns Ferry Nuclear Plant (BFN), Units 1, 2, and 3 Technical Specifications (TS) Change 474 License Amendment Request to Add a TS 3.7.3, "Control Room Emergency Ventilation (CREV) System," Action to Address Inoperable CREV High Efficiency Particulate Air (HEPA) Filter and/or Charcoal Adsorbers Proposed Technical Specifications Page - Markups

CREV System 3.7.3 3.7 PLANT SYSTEMS 3.7.3 Control Room Emergency Ventilation (CREV) System LCO 3.7.3 Two CREV subsystems shall be OPERABLE.

NOTE ----------------------------------------

The main control room envelope (CRE) boundary may be opened intermittently under administrative control.

APPLICABILITY:

MODES 1, 2, and 3, during operations with a potential for draining the reactor vessel (OPDRVs).

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One CREV subsystem A.1 Restore CREV subsystem 7 days inoperable for reasons to OPERABLE status.

other than Condition B, C, or D.

B. One or more CREV B.1 Initiate action to Immediately subsystems inoperable implement mitigating due to inoperable CRE actions boundary in MODES 1, 2, ord 3.

AND B.2 Verify mitigating actions 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months ensure CRE occupant exposures to radiological hazards will not exceed limits, and verify the CRE occupants are protected from smoke and chemical hazards.

AND B.3 Restore CRE boundary to 90 days OPERABLE status.

(continued)

BFN-UNIT 1 3.7-8 Amendment No. 246, 254-, 2-7-5,

CREV System 3.7.3 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME C. Two CREV subsystems C. I Restore HEPA filter and 7 days inoperable due to one charcoal adsorber to inoperable High Efficiency OPERABLE status.

Particulate Air (HEPA) filter or charcoal adsorbers which do not impact ability of CREV subsystems to meet flowrate requirements specified in the Ventilation Filter Testing Program (VFTP).

D. One CREV subsystem D. 1 Restore charcoal 14 days inoperable due to adsorber to OPERABLE inoperable charcoal status.

adsorber which does not impact the ability of CREV subsystem to meet flowrate requirements specified in the VFTP.

EG.

Required Action and EG.1 Be in MODE 3.

12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months associated Completion Time of Condition A, B, C, AND or D -OF-B-not met in MODE 1, 2, or 3.

EG.2 Be in MODE 4.

36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months (continued)

BFN-UNIT 1 3.7-8a Amendment No. 246, 2-54-, 27-5,

CREV System 3.7.3 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME F9.

Required Action and F9.1 Place OPERABLE CREV Immediately associated Completion subsystem in Time of Condition A or D pressurization mode.

not met during OPDRVs.

OR F9.2 Initiate action to suspend Immediately OPDRVs.

GE.

Two CREV GE-.1 Enter LCO 3.0.3.

Immediately subsystems inoperable in MODE 1, 2, or 3 for reasons other than Condition B or C.

(continued)

BFN-UNIT I 3.7-9 Amendment No. 2-34, 246, 2--1-,

CREV System 3.7.3 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME HF. Required Action and HF.1 Initiate action to suspend Immediately associated Completion OPDRVs.

Time of Condition C not met during OPDRVs.

OR Two CREV subsystems inoperable during OPDRVs for reasons other than Condition C.

OR One or more CREV subsystems inoperable due to an inoperable CRE Boundary during OPDRVs.

BFN-UNIT 1 3.7-10, Amendment No. 246, 2&1-, 2-7-,

CREV System 3.7.3 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.3.1 Operate each CREV subsystem for _Ž 10 31 days continuous hours with the heaters operating.

SR 3.7.3.2 Perform required CREV filter testing in In accordance accordance with the Ventilation Filter TeSting with the VFTP P-egFam-VFTP).

SR 3.7.3.3 Verify each CREV subsystem actuates on an 24 months actual or simulated initiation signal.

SR 3.7.3.4 Perform required CRE unfiltered air inleakage In accordance testing in accordance with the Control Room with the Control Envelope Habitability Program.

Room Envelope Habitability Program BFN-UNIT 1 3.7-11 Amendment No. 235, 2-7-5,

CREV System 3.7.3 3.7 PLANT SYSTEMS 3.7.3 Control Room Emergency Ventilation (CREV) System LCO 3.7.3 Two CREV subsystems shall be OPERABLE.

NOTE -----------------------------------

The main control room envelope (CRE) boundary may be opened intermittently under administrative control.

APPLICABILITY:

MODES 1, 2, and 3, during operations with a potential for draining the reactor vessel (OPDRVs).

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One CREV subsystem A.1 Restore CREV subsystem 7 days inoperable for reasons to OPERABLE status.

other than Condition B, C, or D.

B. One or more CREV B.1 Initiate actions to Immediately subsystems inoperable implement mitigating due to inoperable CRE actions.

boundary in MODES 1, 2, or4 3.

AND B.2 Verify mitigating actions 24 Hours ensure CRE occupant exposures to radiological hazards will not exceed limits, and verify the CRE occupants are protected from smoke and chemical hazards.

AND B.3 Restore CRE boundary to 90 days OPERABLE status.

(continued)

BFN-UNIT 2 3.7-9 Amendment No. 283, 290, W02,

CREV System 3.7.3 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME C. Two CREV subsystems C. I Restore HEPA filter and 7 days inoperable due to one charcoal adsorber to inoperable High Efficiency OPERABLE status.

Particulate Air (HEPA) filter or charcoal adsorbers which do not impact ability of CREV subsystems to meet flowrate requirements specified in the Ventilation Filter Testing Program (VFTP).

D. One CREV subsystem D. I Restore charcoal 14 days inoperable due to adsorber to OPERABLE inoperable charcoal status.

adsorber which does not impact the ability of CREV subsystem to meet flowrate requirements specified in the VFTP.

EG.

Required Action and EG.1 Be in MODE 3.

12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months associated Completion Time of Condition A, B, C, AND or D -er-B-not met in MODE 1, 2, or 3.

EG.2 Be in MODE 4.

36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months (continued)

BFN-UNIT 2 3.7-9a Amendment No. 288, 2-99, WO2,

CREV System 3.7.3 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME FP.

Required Action and FD.1 Place OPERABLE CREV Immediately associated Completion subsystem in Time of Condition A or D pressurization mode.

not met during OPDRVs.

OR FD.2 Initiate action to suspend Immediately OPDRVs.

GE. Two CREV subsystems GE-.1 Enter LCO 3.0.3.

Immediately inoperable in MODE 1, 2, or 3 for reasons other than Condition B or C.

(continued)

BFN-UNIT 2 3.7-10 Amendment No. 254, 2-83, 2-9,

CREV System 3.7.3 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME HR-. Required Action and H.F.1 Initiate action to suspend Immediately associated Completion OPDRVs.

Time of Condition C not met during OPDRVs OR Two CREV subsystems inoperable during OPDRVs for reasons other than Condition C.

OR One or more CREV subsystems inoperable due to an inoperable CRE Boundary during OPDRVs.

BFN-UNIT 2 3.7-11 Amendment No. 283, 2-90, 2,

CREV System 3.7.3 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.3.1 Operate each CREV subsystem for _Ž 10 31 days continuous hours with the heaters operating.

SR 3.7.3.2 Perform required CREV filter testing in In accordance accordance with the Ventilation Filter Testing with the VFTP P-Feg~amVFTP).

SR 3.7.3.3 Verify each CREV subsystem actuates on an 24 months actual or simulated initiation signal.

SR 3.7.3.4 Perform required CRE unfiltered air inleakage In accordance testing in accordance with the Control Room with the Control Envelope Habitability Program.

Room Envelope Habitability Program BFN-UNIT 2 3.7-12 Amendment No. 2-55, 302,

CREV System 3.7.3 3.7 PLANT SYSTEMS 3.7.3 Control Room Emergency Ventilation (CREV) System LCO 3.7.3 Two CREV subsystems shall be OPERABLE.

NOTE The main control room envelope (CRE) boundary may be opened intermittently under administrative control.

APPLICABILITY:

MODES 1, 2, and 3, during operations with a potential for draining the reactor vessel (OPDRVs).

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One CREV subsystem A.1 Restore CREV subsystem 7 days inoperable for reasons to OPERABLE status.

other than Condition B, C, or D.

B. One or more CREV B.1 Initiate actions to Immediately subsystems inoperable implement mitigating due to inoperable CRE actions.

boundary in MODES 1,2, or4 3.

AND B.2 Verify mitigating actions 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months ensure CRE occupant exposures to radiological hazards will not exceed limits, and verify the CRE occupants are protected from smoke and chemical hazards.

AND B.3 Restore CRE boundary to 90 days OPERABLE status.

(continued)

BFN-UNIT 3 3.7-9 Amendment No. 241-, 249, 2-64-,

CREV System 3.7.3 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME C. Two CREV subsystems C. 1 Restore HEPA filter and 7 days inoperable due to one charcoal adsorber to inoperable High Efficiency OPERABLE status.

Particulate Air (HEPA) filter or charcoal adsorbers which do not impact ability of CREV subsystems to meet flowrate requirements specified in the Ventilation Filter Testing Program (VFTP).

D. One CREV subsystem D. 1 Restore charcoal 14 days inoperable due to adsorber to OPERABLE inoperable charcoal status.

adsorber which does not impact the ability of CREV subsystem to meet flowrate requirements specified in the VFTP.

EG.

Required Action and EG.1 Be in MODE 3.

12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months associated Completion Time of Condition A, B, C, AND or D -e9-FBnot met in MODE 1, 2, or 3.

EG.2 Be in MODE 4.

36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months (continued)

BFN-UNIT 3 3.7-9a Amendment No. 244, 249, 26-1-,

CREV System 3.7.3 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME FD.

Required Action and FQ.1 Place OPERABLE CREV Immediately associated Completion subsystem in Time of Condition A or D pressurization mode.

not met during OPDRVs.

OR FD.2 Initiate action to suspend Immediately OPDRVs.

GE.

Two CREV GE-.1 Enter LCO 3.0.3.

Immediately subsystems inoperable in MODE 1, 2, or 3 for reasons other than Condition B or C.

(continued)

BFN-UNIT 3 3.7-10 Amendment No. 244, 244-, 248,

CREV System 3.7.3 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME HF. Required Action and H,.1 Initiate action to suspend Immediately associated Completion OPDRVs.

Time of Condition C not met during OPDRVs.

OFR Two CREV subsystems

-inoperable during

-OPDRVs for reasons other than Condition C.

OR One or more CREV subsystems inoperable due to an inoperable CRE Boundary during OPDRVs.

BFN-UNIT 3 3.7-11 Amendment No. 244-, 249, 2-64-,

CREV System 3.7.3 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.3.1 Operate each CREV subsystem for Ž_ 10 31 days continuous hours with the heaters operating.

SR 3.7.3.2 Perform required CREV filter testing in In accordance accordance with the Ventilation Filter Testing with the VFTP Po)am-VFTP).

SR 3.7.3.3 Verify each CREV subsystem actuates on an 24 months actual or simulated initiation signal.

SR 3.7.3.4 Perform required CRE unfiltered air inleakage In accordance testing in accordance with the Control Room with the Control Envelope Habitability Program.

Room Envelope Habitability Program BFN-UNIT 3 3.7-12 Amendment No. 2-1-5, 264, Browns Ferry Nuclear Plant (BFN), Units 1, 2, and 3 Technical Specifications (TS) Change 474 License Amendment Request to Add a TS 3.7.3, "Control Room Emergency Ventilation (CREV) System," Action to Address Inoperable CREV High Efficiency Particulate Air (HEPA) Filter and/or Charcoal Adsorbers Proposed Technical Specifications Bases Pages - Markups

CREV System B 3.7.3 B 3.7 PLANT SYSTEMS B 3.7.3 Control Room Emergency Ventilation (CREV) System BASES BACKGROUND The CREV System provides a protected environment from which occupants can control the unit following an uncontrolled release of radioactivity.

The safety related function of the CREV System includes two independent and redundant high efficiency air filtration subsystems for emergency treatment of outside supply air and a Control Room Envelope (CRE) boundary that limits the inleakage of unfiltered air. The CREV System has a high efficiency particulate air (HEPA) filter bank in the portion of the inlet piping common to both subsystems. Each CREV subsystem consists of a motor-driven fan, an electric duct air heater, an activated charcoal adsorber section, an electric charcoal heater, and the associated ductwork, valves or dampers, doors, barriers, and instrumentation. The HEPA filter bank removes particulate matter, which may be radioactive.

The charcoal adsorbers provide a holdup period for gaseous iodine, allowing time for decay; however, no credit is taken in the analyses for the coharcoeal adsorbers.

The CRE is the area within the confines of the CRE boundary that contains the spaces that control room occupants inhabit to control the unit during normal and accident conditions. This area encompasses the control room, and may encompass other non-critical areas to which frequent personnel access or continuous occupancy is not necessary in the event of an accident. The CRE is protected during normal operation, natural event and accident conditions. The CRE boundary is the combination of walls, floor, roof, ducting, doors, penetrations and equipment that physically form the CRE. The OPERABILITY of the CRE boundary must be (continued)

BFN-UNIT I B 3.7-17 Revision 0-29 Amendment 27-5,

CREV System B 3.7.3 BASES BACKGROUND (continued) maintained to ensure that the inleakage of unfiltered air into the CRE will not exceed the inleakage assumed in the licensing basis analysis of design basis accident (DBA) consequences to CRE occupants. The CRE and its boundary are defined in the Control Room Envelope Habitability Program.

Upon receipt of the initiation signal(s) (indicative of conditions that could result in radiation exposure to CRE occupants), the CREV System automatically switches to the pressurization mode of operation to minimize infiltration of contaminated air into the CRE. A system of dampers isolates the CRE. Outside air is taken in through the CREV System ventilation intake and is passed through one of the charcoal adsorber filter subsystems for removal of airborne radioactive particles.

The CREV System is designed to maintain a habitable environment in the CRE for 30 day continuous occupancy after a DBA without exceeding 5 REM total effective dose equivalent (TEDE). A single CREV subsystem operating at a flow of 3000 cfm +/-10 percent will pressurize the CRE to about 0.125 inches water gauge to minimize infiltration of air from all surrounding areas adjacent to CRE boundary and the outdoors. CREV System operation in maintaining CRE habitability is discussed in the FSAR, Section 10.12 (Ref. 1).

APPLICABLE SAFETY ANALYSES The ability of the CREV System to maintain the habitability of the CRE is an explicit assumption for the safety analyses presented in the FSAR, Chapters 10 and 14 (Refs. 2 and 3, respectively). The pressurization mode of the CREV System is assumed to operate following a DBA, as discussed in the FSAR, Section 14.6 (Ref. 4). The analyses for radiological doses to CRE occupants as a result of the various DBAs are summarized in References 3 and 10. No credit is taken in the analysis for filtration by the HEPA filter or charcoal adsorbers. Ne-sigle atiýVe, failu-,re Will cause the loss of fiteFred outside air fre-m the9 (continued)

BFN-UNIT 1 B 3.7-18 Revision 0, 2-9 Amendment 2-7-5,

CREV System B 3.7.3 BASES APPLICABLE No single active failure will cause the loss of pressurization SAFETY ANALYSIS capability using outside air from the CRE.

(continued)

There are no offsite or onsite hazardous chemicals that would pose a credible threat to CRE habitability (Ref 9).

Consequently, engineering controls for the CRE are not required to ensure habitability against chemical threat.

The evaluation of a smoke challenge demonstrated that smoke will not result in the inability of the CRE occupants to control the reactor either from the control room or remote shutdown system (Ref 9). The assessment verified that a fire or smoke event anywhere within the plant should not simultaneously render the remote shutdown system and the CRE uninhabitable, nor would it prevent access from the CRE to the remote shutdown system in the event remote shutdown is required. No automatic CREV actuation is required for hazardous chemical releases or smoke and no Surveillance Requirements are required to verify OPERABILITY in cases of hazardous chemicals or smoke.

The CREV System satisfies Criterion 3 of the NRC Policy Statement (Ref. 6).

(continued)

BFN-UNIT 1 B 3.7-18a Revision Q-, 2-8 Amendment 2-7-,

CREV System B 3.7.3 BASES (continued)

LCO Two redundant subsystems of the CREV System are required to be OPERABLE to ensure that at least one is available, if a single active failure disables the other subsystem. Total CREV System failure, such as from a loss of both ventilation subsystems or from an inoperable CRE boundary, could result in exceeding a TEDE of 5 REM to the CRE occupants in the event of a DBA.

Each CREV subsystem is considered OPERABLE when the individual components necessary to limit CRE occupant exposure are OPERABLE. A subsystem is considered OPERABLE when its associated:

a. Fan is OPERABLE;

b. HEPA filter and charcoal adsorbers are not excessively restricting flow and are capable of performing their filtration functions; and

c. The electric duct heater, ductwork, and dampers are OPERABLE.

Charcoal adsorbers are considered OPERABLE when Ventilation Filter Testing Program (VFTP) acceptance criteria are met and the electric duct heater functions to support the charcoal adsorber function. The HEPA filter is considered OPERABLE when VFTP acceptance criteria are met.

In order for the CREV subsystems to be considered OPERABLE, the CRE boundary must be maintained such that the CRE occupant dose from a large radioactive release does not exceed the calculated dose in the licensing basis consequences analyses for DBAs, and that the CRE occupants are protected from hazardous chemicals and smoke.

BFN does not have automatic CREV actuations for hazardous chemicals or smoke. Current practices at BFN do not utilize (continued)

BFN-UNIT 1 B 3.7-19 Revision 4, 2-9 Amendment 2-7-5,

CREV System B 3.7.3 anfifi ++

k^a-nn ;__

rhn,.I kh-

'Arr +r nr"

ýrnif~ll'o']*

%Tt *1 "

ttni l*t

'n l thc ORE. Smoke is no~t considered in the current BEN safety analysis. Thoroforo, BE3N has no) spocific limits on chemical hazards or smoko.

BASES LCO (continued) chemicals of sufficient quantity to present a chemical hazard to the CRE. Smoke is not considered in the current BFN safety analysis. Therefore, BFN has no specific limits on chemical hazards or smoke.

The LCO is modified by a Note allowing the CRE boundary to be opened intermittently under administrative controls. This Note only applies to openings in the CRE boundary that can be rapidly restored to the design condition, such as doors, hatches, floor plugs, and access panels. For entry and exit through doors the administrative control of the opening is performed by the person(s) entering or exiting the area. For other openings, these controls should be proceduralized and consist of stationing a dedicated individual at the opening who is in continuous communication with the operators in the CRE.

This individual will have a method to rapidly close the opening and to restore the CRE boundary to a condition equivalent to the design condition when a need for CRE isolation is indicated.

(continued)

BFN-UNIT 1 B 3.7-19a Revision @, 2-Amendment 27-5,

CREV System B 3.7.3 BASES (continued)

APPLICABILITY

-In MODES 1, 2, and 3, the CREV System must be OPERABLE to ensure that the CRE will remain habitable during and following a DBA, since the DBA could lead to a fission product release.

In MODES 4 and 5, the probability and consequences of a DBA are reduced because of the pressure and temperature limitations in these MODES. Therefore, maintaining the CREV System OPERABLE is not required in MODE 4 or 5, except for during operations with potential for draining the reactor vessel (OPDRVs).

ACTIONS A._1 With one CREV subsystem inoperable, for reasons other than an inoperable CRE boundary, or inoperable HEPA filter or inoperable charcoal adsorbers (which do not impact the ability of the CREV subsystems to meet flowrate requirements specified in the VFTP), the inoperable CREV subsystem must be restored to OPERABLE status within 7 days. With the unit in this condition, the remaining OPERABLE CREV subsystem is adequate to perform the CRE occupant protection function.

However, the overall reliability is reduced because a failure in the OPERABLE subsystem could result in loss of the CREV System function. The 7 day Completion Time is based on the low probability of a DBA occurring during this time period, and that the remaining subsystem can provide the required capabilities.

(continued)

BFN-UNIT 1 B 3.7-20 Revision 0, 29 Amendment No. 246, 2-7-5,

CREV System B 3.7.3 BASES ACTIONS B.1, B2 and B3 (continued)

If the unfiltered inleakage of potentially contaminated air past the CRE boundary and into the CRE can result in a CRE occupant radiological dose greater than the calculated dose of the licensing basis analyses of DBA consequences (allowed to be up to 5 REM TEDE) the CRE boundary is inoperable.

As discussed in the Applicable Safety Analysis Section, the BFN licensing bases notes that CRE inleakage limits for hazardous chemicals and smoke are not needed to protect the CRE occupants. Since the limit established for radiological events is limiting, verification of smoke and chemical hazards by administrative means is acceptable for an inoperable CRE boundary. Verification that the periodic check of onsite and offsite hazardous chemical sources has been performed within the time limit defined by the Control Room Habitability Program is an acceptable means to ensure the CRE occupants are protected from chemical hazards and smoke.

Actions must be taken to restore an OPERABLE CRE boundary within 90 days.

During the period that the CRE boundary is considered inoperable, action must be initiated to implement mitigating actions to lessen the effect on CRE occupants from the potential hazards of a radiological or chemical event or a challenge from smoke. Actions must be taken within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to verify that in the event of a DBA, the mitigating actions will ensure that CRE occupant radiological exposures will not exceed the calculated dose of the licensing basis analyses of DBA consequences and that CRE occupants are protected from hazardous chemicals and smoke. These mitigating actions (i.e., actions that are taken to offset the consequences of the inoperable CRE boundary) should be preplanned for implementation upon entry into the condition, regardless of whether entry is intentional or unintentional. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months (continued)

BFN-UNIT 1 B 3.7-21 Revision Q, 2-9 Amendment No.-246, 275 October 16, 2009

CREV System B 3.7.3 BASES ACTIONS B.1, B2 and B3 (continued)

Completion Time is reasonable based on low probability of a DBA occurring during this time period and the use of mitigating actions. The 90 day Completion Time is reasonable based on the determination that the mitigating actions will ensure protection of CRE occupants within analyzed limits while limiting the probability that CRE occupants will have to implement protective measures that may adversely affect their ability to control the reactor and maintain it in a safe-shutdown condition in the event of a DBA. In addition, the 90 day Completion Time is a reasonable time to diagnose, plan and possibly repair, and test most problems within the CRE boundary.

C.. 1 With two CREV subsystems inoperable due to a HEPA filter inoperable or both CREV subsystems' charcoal adsorbers inoperable, which do not impact the ability of the CREV subsystems to meet flowrate requirements specified in the VFTP, the HEPA filter and one of the charcoal adsorbers must be restored within 7 days. The 7 day Completion Time is based on the analysis for radiological dose to CRE occupants (Ref. 10), which has determined that the CRE 30 day dose after a DBA does not exceed 5 rem (TEDE) without credit for either the HEPA filter or the charcoal adsorbers.

D.1 With one CREV subsystem inoperable due to one inoperable charcoal adsorber, which does not impact the ability of the associated CREV subsystem to meet flowrate requirements specified in the VFTP, the charcoal adsorber must be restored within 14 days. The 14 day Completion Time is based on the analysis for radiological dose to CRE occupants (Ref. 10),

which has determined that the CRE 30 day dose after a DBA does not exceed 5 rem (TEDE) without credit for either (continued)

BFN-UNIT 1 B 3.7-21a Revision Q, 2-9 Amendment No.-246, 2-7-5,

CREV System B 3.7.3 BASES ACTIONS the HEPA filter or the charcoal adsorbers, and the capability of (continued) the remaining OPERABLE CREV subsystem.

EG.1 and EG.2 In MODE 1, 2, or 3, if the inoperable CREV subsystem(s) or the CRE boundary cannot be restored to OPERABLE status within the required Completion Time, the unit must be placed in a MODE that minimizes accident risk. To achieve this status, the unit must be placed in at least MODE 3 within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and in MODE 4 within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The allowed Completion Times are reasonable, based on operating experience, to reach the required unit conditions from full power conditions in an orderly manner and without challenging unit systems.

F9.1 and F9.2 During OPDRVs, if the inoperable CREV subsystem cannot be restored to OPERABLE status within the required Completion Time, the OPERABLE CREV subsystem may be placed in the pressurization mode. This action ensures that the remaining subsystem is OPERABLE, that no failures that would prevent automatic actuation will occur, and that any active failure will be readily detected.

An alternative to Required Action FD.1 is to immediately initiate actions to suspend OPDRVs to minimize the probability of a vessel draindown and the subsequent potential for fission product release. Actions must continue until the OPDRVs are suspended.

(continued)

BFN-UNIT 1 B 3.7-22 Revision Q-, 2-Amendment No.-2-46, 2-7-5,

CREV System B 3.7.3 BASES ACTIONS (continued)

G&-.1 If both CREV subsystems are inoperable in MODE 1, 2, or 3 for reasons other than an inoperablo ORE (i.e., Condition B or Condition C), the CREV System may not be capable of performing the intended function and the unit is in a condition outside the accident analyses. Therefore, LCO 3.0.3 must be entered immediately.

HF-.1 During OPDRVs, a) with two CREV subsystems inoperable for reasons other than an inoperable HEPA filter or inoperable charcoal adsorbers, b) er--with one or more CREV subsystems inoperable due to an inoperable CRE boundary, or c) if the HEPA filter and charcoal adsorbers can not be restored to OPERABLE status within the required Completion Time, actions must be initiated immediately to suspend OPDVRs to minimize the probability of a vessel draindown and subsequent potential for fission product release. Actions must continue until the OPDRVs are suspended.

(continued)

BFN-UNIT 1 B 3.7-23 Revision Q, 2-9 Amendment No. 246, 27-5,

CREV System B 3.7.3 BASES (continued)

SURVEILLANCE SR 3.7.3.1 REQUIREMENTS This SR verifies that a subsystem in a standby mode starts on demand and continues to operate. Standby systems should be checked periodically to ensure that they start and function properly. As the environmental and normal operating conditions of this system are not severe, testing each subsystem once every month provides an adequate check on this system.

Monthly heater operation dries out any moisture that has accumulated in the charcoal as a result of humidity in the ambient air. The CREV System must be operated for > 10 continuous hours with the heaters energized to dry out any moisture and to demonstrate the function of the system.

Furthermore, the 31 day Frequency is based on the known reliability of the equipment and the two subsystem redundancy available.

SR 3.7.3.2 This SR verifies that the required CREV testing is performed in accordance with the Ventilation Filter Testing Program (VFTP).

The VFTP includes testing HEPA filter performance, charcoal adsorber efficiency, minimum system flow rate, and the physical properties of the activated charcoal (general use and following specific operations). Specific test frequencies and additional information are discussed in detail in the VFTP.

(continued)

BFN-UNIT 1 B 3.7-24 Revision 0

CREV System B 3.7.3 BASES SURVEILLANCE REQUIREMENTS (continued)

SR 3.7.3.3 This SR verifies that on an actual or simulated initiation signal, each CREV subsystem starts and operates. This SR includes verification that dampers necessary for proper CREV operation function as required. The LOGIC SYSTEM FUNCTIONAL TEST in SR 3.3.7.1.4 and SR 3.3.7.1.6 overlaps this SR to provide complete testing of the safety function. The Frequency of 24 months is based on BFN's normal operating cycle.

SR 3.7.3.4 This SR verifies the OPERABILITY of the CRE boundary by testing for unfiltered air inleakage past the CRE boundary and into the CRE. The details of the testing are specified in the Control Room Envelope Habitability Program.

The CRE is considered habitable when the radiological dose to CRE occupants calculated in the licensing basis analyses of DBA consequences is no more that 5 REM TEDE and the CRE occupants are protected from hazardous chemicals and smoke.

There is no automatic CREV actuation for hazardous chemical releases or smoke and there are no Surveillance Requirements to verify the OPERABILITY in cases of hazardous chemicals or smoke. This SR verifies that the unfiltered air inleakage into the CRE is no greater than the flow rate assumed in the licensing basis analysis of DBA consequences. When unfiltered air inleakage is greater than the assumed flow rate, Condition B must be entered. Required Action B.3 allows time to restore the CRE boundary to OPERABLE status provided mitigating actions can ensure that the CRE remains within the licensing basis habitability limits for occupants following an accident.

Compensatory measures are discussed in Regulatory Guide 1.196, Section C.2.7.3, (Ref. 6) which endorses, with exceptions, NEI 99-03, Section 8.4 and Appendix F (Ref. 7).

These compensatory measures may also be used as mitigating actions as required by Required Action B.2. Temporary analytical methods may also be used as compensatory (continued)

BFN-UNIT 1 B 3.7-25 Amendment No. 235, 275 October 16, 2009

CREV System B 3.7.3 BASES SURVEILLANCE REQUIREMENTS SR 3.7.3.4 (continued) measures to restore OPERABILITY (Ref. 8). Options for restoring the CRE boundary to OPERABLE status include changing the licensing basis DBA consequences analysis, repairing the CRE boundary, or a combination of these actions.

Depending upon the nature of the problem and the corrective action, a full scope inleakage test may not be necessary to establish that the CRE boundary has been restored to OPERABLE status.

(continued)

BFN-UNIT 1 B 3.7-25a Amendment No. 2-W, 275 October 16, 2009

CREV System B 3.7.3 BASES (continued)

REFERENCES

1. FSAR, Section 10.12.

2. FSAR, Chapter 10.

3. FSAR, Chapter 14.

4. FSAR, Section 14.6.

5. NRC No.93-102, "Final Policy Statement on Technical Specification Improvements," July 23, 1993.

6. NRC Regulatory Guide 1.196, "Control Room Habitability At Light-Water Power Reactors," January 2007.

7. NEI 99-03, "Control Room Habitability Assessment," June 2001.

8. Letter from Eric J. Leeds (NRC) to James W. Davis (NEI) dated January 30, 2004, "NEI Draft White Paper, Use of Generic Letter 91-18 Process and Alternative Source Terms in the Context of Control Room Habitability," (ADAMS Accession No. ML040300694).

9. FSAR, Chapter 10.12.5.3, Toxic Gas Protection.

10. TVA Design Output Calculation NDQ0031920075, "Control Room and Offsite Dose Due to a LOCA," Revision 21.

BFN-UNIT 1 B 3.7-25b Amendment No. 2-35, 27-5,

CREV System B 3.7.3 B 3.7 PLANT SYSTEMS B 3.7.3 Control Room Emergency Ventilation (CREV) System BASES BACKGROUND The CREV System provides a protected environment from which occupants can control the unit following an uncontrolled release of radioactivity.

The safety related function of the CREV System includes two independent and redundant high efficiency air filtration subsystems for emergency treatment of outside supply air and a Control Room Envelope (CRE) boundary that limits the inleakage of unfiltered air. The CREV System has a high efficiency particulate air (HEPA) filter bank in the portion of the inlet piping common to both subsystems. Each CREV subsystem consists of a motor-driven fan, an electric duct air heater, an activated charcoal adsorber section, an electric charcoal heater, and the associated ductwork, valves or dampers, doors, barriers and instrumentation. The HEPA filter bank removes particulate matter, which may be radioactive.

The charcoal adsorbers provide a holdup period for gaseous iodine, allowing time for decay; hoo*ver, no) crdit is taken in the analyscs for thee cdhiarcoal adsorberc.

The CRE is the areas within the confines of the CRE boundary that contains the spaces that control room occupants inhabit to control the unit during normal and accident conditions. This area encompasses the control room, and may encompass other non-critical areas to which frequent personnel access or continuous occupancy is not necessary in the event of an accident. The CRE is protected during normal operation, natural event and accident conditions. The CRE boundary is the combination of wall, floor, root, ducting, doors, penetrations and equipment that physically form the CRE. The OPERABILITY of the CRE boundary must be maintained to ensure that the inleakage of unfiltered air in the CRE will not (continued)

BFN-UNIT 2 B 3.7-17 Revision 0, 2-g Amendment No. 3Q2,

CREV System B 3.7.3 BASES BACKGROUND (continued) exceed the inleakage assumed in the licensing basis analysis of design basis accident (DBA) consequences to CRE occupants. The CRE and its boundary are defined in the Control Room Envelope Habitability Program.

Upon receipt of the initiation signal(s) (indicative of conditions that could result in radiation exposure to CRE occupants), the CREV System automatically switches to the pressurization mode of operation to minimize infiltration of contaminated air into the CRE. A system of dampers isolates the CRE. Outside air is taken in through the CREV System ventilation intake and is passed through one of the charcoal adsorber filter subsystems for removal of airborne radioactive particles.

The CREV System is designed to maintain a habitable environment in the CRE for a 30 day continuous occupancy after a DBA without exceeding 5 REM total effective dose equivalent (TEDE). A single CREV subsystem operating at a flow rate of 3000 CFM + 10 percent will pressurize the CRE to about 0.125 inches water gauge to minimize infiltration of air from all surrounding areas adjacent to CRE boundary and the outdoors. CREV System operation in maintaining CRE habitability is discussed in the FSAR, Section 10.12 (Ref. 1).

(continued)

BFN-UNIT 2 B 3.7-17a-Revision 0, 2-9 Amendment No. 302 October 16, 2009

CREV System B 3.7.3 BASES (continued)

APPLICABLE SAFETY ANALYSES The ability of the CREV System to maintain the habitability of the CRE is an explicit assumption for the safety analyses presented in the FSAR, Chapters 10 and 14 (Refs. 2 and 3, respectively). The pressurization mode of the CREV System is assumed to operate following a DBA, as discussed in the FSAR, Section 14.6 (Ref. 4). The analyses for radiological doses to CRE occupants as a result of the various DBAs are summarized in References 3 and 10. No credit is taken in the analyses for filtration by the HEPA filter or charcoal adsorbers. No single active failure will cause the loss of pressurization capability using filteredoutside air from the CRE.

There are no offsite or onsite hazardous chemicals that would pose a credible threat to CRE habitability (Ref. 9).

Consequently, engineering controls for the CRE are not required to ensure habitability against chemical threat.

The evaluation of a smoke challenge demonstrated that smoke will not result in the inability of the CRE occupants to control the reactor either from the control room or remote shutdown system (Ref 9). The assessment verified that a fire or smoke event anywhere within the plant should not simultaneously render the remote shutdown system and the CRE uninhabitable, nor would it prevent access from the CRE to the remote shutdown system in the event remote shutdown is required. No automatic CREV actuation is required for hazardous chemical releases or smoke and no Surveillance Requirements are required to verify OPERABILITY in cases of hazardous chemicals or smoke.

The CREV System satisfies Criterion 3 of the NRC Policy Statement (Ref. 6).

(continued)

BFN-UNIT 2 B 3.7-18 Revision 0, 29 Amendment No. 3Q,

CREV System B 3.7.3 BASES (continued)

LCO Two redundant subsystems of the CREV System are required to be OPERABLE to ensure that at least one is available, if a single active failure, such as from a loss of both ventilation subsystems or from an inoperable CRE boundary, disables the other subsystem. Total system failure could result in exceeding a TEDE of 5 REM to the CRE occupants in the event of a DBA.

Each CREV subsystem is considered OPERABLE when the individual components necessary to limit CRE occupant exposure are OPERABLE in both subsystems. A subsystem is considered OPERABLE when its associated:

a. Fan is OPERABLE;

b. HEPA filter and charcoal adsorbers are not excessively restricting flow and are capable of performing their filtration functions; and

c. The electric duct heater, ductwork, and dampers are OPERABLE.

Charcoal adsorbers are considered OPERABLE when Ventilation Filter Testing Program (VFTP) acceptance criteria are met and the electric duct heater functions to support the charcoal adsorber function. The HEPA filter is considered OPERABLE when VFTP acceptance criteria are met.

In order for the CREV subsystem to be considered OPERABLE, the CRE boundary must be maintained such that the CRE occupant dose from a large radioactive release does not exceed the calculated dose in the licensing basis consequences analyses for DBAs, and that the CRE occupants are protected from hazardous chemicals and smoke.

BFN does not have automatic CREV actuations for hazardous chemicals or smoke. Current practices at BFN do not utilize (continued)

BFN-UNIT 2 B 3.7-19 Revision 0, 2-9 Amendment No. 2-3, 302,

CREV System B 3.7.3 BASES LCO (continued) chemicals of sufficient quantity to present a chemical hazard to the CRE. Smoke is not considered in the current BFN safety analysis. Therefore, BFN has no specific limits on chemical hazards or smoke.

The LCO is modified by a Note allowing the CRE boundary to be opened intermittently under administrative controls. This Note only applies to openings in the CRE boundary that can be rapidly restored to the design condition, such as doors, hatches, floor plugs and access panels. For entry and exit through doors the administrative control of the opening is performed by the person(s) entering or exiting the area. For other openings, these controls should be proceduralized and consist of stationing a dedicated individual at the opening who is in continuous communication with the operators and CRE.

This individual will have a method to rapidly close the opening and to restore the CRE boundary to a condition equivalent to the design condition when a need for CRE isolation is indicated.

(continued)

BFN-UNIT 2 B 3.7-19a Revision 0, 2-9 Amendment No. 2-83, W2,

CREV System B 3.7.3 BASES (continued)

APPLICABILITY In MODES 1, 2, and 3, the CREV System must be OPERABLE to ensure that the CRE will remain habitable during and following a DBA, since the DBA could lead to a fission product release.

In MODES 4 and 5, the probability and consequences of a DBA are reduced because of the pressure and temperature limitations in these MODES. Therefore, maintaining the CREV System OPERABLE is not required in MODE 4 or 5, except for during operations with potential for draining the reactor vessel (OPDRVs).

ACTIONS A.1 With one CREV subsystem inoperable, for reasons other than an inoperable CRE boundary, or inoperable HEPA filter or inoperable charcoal adsorbers (which do not impact the ability of the CREV subsystems to meet flowrate requirements specified in the VFTP), the inoperable CREV subsystem must be restored to OPERABLE status within 7 days. With the unit in this condition, the remaining OPERABLE CREV subsystem is adequate to perform the CRE occupant protection function.

However, the overall reliability is reduced because a failure in the OPERABLE subsystem could result in loss of the CREV System function. The 7 day Completion Time is based on the low probability of a DBA occurring during this time period, and that the remaining subsystem can provide the required capabilities.

(continued)

BFN-UNIT 2 B 3.7-20 Revision 0, 2-9 Amendment

CREV System B 3.7.3 BASES ACTIONS B.1, B.2, and B.3 (continued)

If the unfiltered inleakage of potentially contaminated air past the CRE boundary and into the CRE can result in a CRE occupant radiological dose greater than the calculated dose of the licensing basis analyses of DBA consequences (allowed to be up to 5 REM TEDE) the CRE boundary is inoperable.

As discussed in the Applicable Safety Analysis Section, the BFN licensing bases notes that CRE inleakage limits for hazardous chemicals and smoke are not needed to protect the CRE occupants. Since the limit established for radiological events is limiting, verification of smoke and chemical hazards by administrative means is acceptable for an inoperable CRE boundary. Verification that the periodic check of onsite and offsite hazardous chemical sources has been performed within the time limit defined by the Control Room Habitability Program is an acceptable means to ensure the CRE occupants are protected from chemical hazards and smoke.

Actions must be taken to restore an OPERABLE CRE boundary within 90 days.

During the period that the CRE boundary is considered inoperable, action must be initiated to implement mitigating actions to lessen the effect on CRE occupants from the potential hazards of a radiological or chemical event or a challenge from smoke. Actions must be taken within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to verify that in the event of a DBA, the mitigating actions will ensure that CRE occupant radiological exposures will not exceed the calculated dose of the licensing basis analyses of DBA consequences and that CRE occupants are protected from hazardous chemicals and smoke. These mitigating actions (i.e., actions that are taken to offset the consequences of the inoperable CRE boundary) should be preplanned for implementation upon entry into the condition, (continued)

BFN-UNIT 2 B 3.7-21 Revision 0, 2-9 Amendment No. 2-83, 302 October 16, 2009

CREV System B 3.7.3 BASES ACTIONS B.1, B.2, and B.3 (continued) regardless of whether entry is intentional or unintentional. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Time is reasonable based on the low probability of a DBA occurring during this time period and the use of mitigating actions. The 90 day Completion Time is reasonable based on the determination that the mitigating actions will ensure protection of CRE occupants within analyzed limits while limiting the probability that CRE occupants will have to implement protective measures that may adversely affect their ability to control the reactor and maintain it in a safe shutdown condition in the event of a DBA. In addition, the 90 day Completion Time is a reasonable time to diagnose, plan and possibly repair, and test most problems within the CRE boundary.

C.__

With two CREV subsystems inoperable due to a HEPA filter inoperable or both CREV subsystems' charcoal adsorbers inoperable, which do not impact the ability of the CREV subsystems to meet flowrate requirements specified in the VFTP, the HEPA filter and one of the charcoal adsorbers must be restored within 7 days. The 7 day Completion Time is based on the analysis for radiological dose to CRE occupants (Ref. 10),

which has determined that the CRE 30 day dose after a DBA does not exceed 5 rem (TEDE) without credit for either the HEPA filter or the charcoal adsorbers.

D.1 With one CREV subsystem inoperable due to one inoperable charcoal adsorber, which does not impact the ability of the associated CREV subsystem to meet flowrate requirements specified in the VFTP, the charcoal adsorber must be restored within 14 days. The 14 day Completion Time is based on the analysis for radiological dose to CRE occupants (Ref 10),

which -has determined that the CRE 30 day dose after (continued)

BFN-UNIT 2 B 3.7-21a Revision 0, 2-9 Amendment No. 283, 302,

CREV System B 3.7.3 BASES ACTIONS a DBA does not exceed 5 rem (TEDE) without credit for either (continued) the HEPA filter or the charcoal adsorbers, and the capability of the remaining OPERABLE CREV subsystem.

EG.1 and EG.2 In MODE 1, 2, or 3, if the inoperable CREV subsystem(s) or the CRE boundary cannot be restored to OPERABLE status within the required Completion Time, the unit must be placed in a MODE that minimizes accident risk. To achieve this status, the unit must be placed in at least MODE 3 within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and in MODE 4 within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The allowed Completion Times are reasonable, based on operating experience, to reach the required unit conditions from full power conditions in an orderly manner and without challenging unit systems.

FD.1 and FD.2 During OPDRVs, if the inoperable CREV subsystem cannot be restored to OPERABLE status within the required Completion Time, the OPERABLE CREV subsystem may be placed in the pressurization mode. This action ensures that the remaining subsystem is OPERABLE, that no failures that would prevent automatic actuation will occur, and that any active failure will be readily detected.

An alternative to Required Action FD.1 is to immediately initiate actions to suspend OPDRVs to minimize the probability of a vessel draindown and the subsequent potential for fission product release. Actions must continue until the OPDRVs are suspended.

(continued)

BFN-UNIT 2 B 3.7-22 Revision 0, 2-9 Amendment No. 28-, W02,

CREV System B 3.7.3 BASES ACTIONS (continued)

GE.1 If both CREV subsystems are inoperable in MODE 1, 2, or 3 for reasons other than an iopeoable CRE (i.o., Condition B or Condition C), the CREV System may not be capable of performing the intended function and the unit is in a condition outside the accident analyses. Therefore, LCO 3.0.3 must be entered immediately.

HF.1 During OPDRVs, a) with two CREV subsystems inoperable for reasons other than an inoperable HEPA filter or inoperable charcoal adsorbers, b),-ei--with one or more CREV subsystems inoperable due to an inoperable CRE boundary, or c) if the HEPA filter and charcoal adsorbers can not be restored to OPERABLE status within the required Completion Time, actions must be initiated immediately to suspend OPDVRs to minimize the probability of a vessel draindown and subsequent potential for fission product release. Actions must continue until the OPDRVs are suspended.

(continued)

BFN-UNIT 2 B 3.7-23 Revision 0-, 2-9 Amendment No. 283, 302,

CREV System B 3.7.3 BASES (continued)

SURVEILLANCE SR 3.7.3.1 REQUIREMENTS This SR verifies that a subsystem in a standby mode starts on demand and continues to operate. Standby systems should be checked periodically to ensure that they start and function properly. As the environmental and normal operating conditions of this system are not severe, testing each subsystem once every month provides an adequate check on this system.

Monthly heater operation dries out any moisture that has accumulated in the charcoal as a result of humidity in the ambient air. The CREV System must be operated for _> 10 continuous hours with the heaters energized to dry out any moisture and to demonstrate the function of the system.

Furthermore, the 31 day Frequency is based on the known reliability of the equipment and the two subsystem redundancy available.

SR 3.7.3.2 This SR verifies that the required CREV testing is performed in accordance with the Ventilation Filter Teoting Program (VFTP-.

The VFTP includes testing HEPA filter performance, charcoal adsorber efficiency, minimum system flow rate, and the physical properties of the activated charcoal (general use and following specific operations). Specific test frequencies and additional information are discussed in detail in the VFTP.

(continued)

BFN-UNIT 2 B 3.7-24 Revision 0 Amendment

CREV System B 3.7.3 BASES SURVEILLANCE REQUIREMENTS (continued)

SR 3.7.3.3 This SR verifies that on an actual or simulated initiation signal, each CREV subsystem starts and operates. This SR includes verification that dampers necessary for proper CREV operation function as required. The LOGIC SYSTEM FUNCTIONAL TEST in SR 3.3.7.1.4 and SR 3.3.7.1.6 overlaps this SR to provide complete testing of the safety function. The frequency of 24 months is based on BFN's normal operating time.

SR 3.7.3.4 This SR verifies the OPERABILITY of the CRE boundary by testing for unfiltered air inleakage past the CRE boundary and into the CRE. The details of the testing are specified in the Control Room Envelope Habitability Program.

The CRE is considered habitable when the radiological dose to CRE occupants calculated in the licensing basis analyses of DBA consequences is no more that 5 REM TEDE and the CRE occupants are protected from hazardous chemicals and smoke.

There is no automatic CREV actuation for hazardous chemical releases or smoke and there are no Surveillance Requirements to verify the OPERABILITY in cases of hazardous chemicals or smoke. This SR verifies that the unfiltered air inleakage into the CRE is no greater than the flow rate assumed in the licensing basis analysis of DBA consequences. When unfiltered air inleakage is greater than the assumed flow rate, Condition B must be entered. Required Action B.3 allows time to restore the CRE boundary to OPERABLE status provided mitigating actions can ensure that the CRE remains within the licensing basis habitability limits for occupants following an accident.

Compensatory measures are discussed in Regulatory Guide 1.196, Section C.2.7.3, (Ref. 6) which endorses, with exceptions, NEI 99-03, Section 8.4 and Appendix F (Ref. 7).

These compensatory measures may also be used as mitigating actions as required by Required Action B.2. Temporary analytical methods may also be used as compensatory (continued)

BFN-UNIT 2 B 3.7-25 Amendment No. 255, 302 October 16, 2009

CREV System B 3.7.3 BASES SURVEILLANCE SR 3.7.3.4 (continued)

REQUIREMENTS measures to restore OPERABILITY (Ref. 8). Options for restoring the CRE boundary to OPERABLE status include changing the licensing basis DBA consequences analysis, repairing the CRE boundary, or a combination of these actions.

Depending upon the nature of the problem and the corrective action, a full scope inleakage test may not be necessary to establish that the CRE boundary has been restored to OPERABLE status.

REFERENCES

1.

FSAR, Section 10.12.

2.

FSAR, Chapter 10.

3.

FSAR, Chapter 14.

4.

FSAR, Section 14.6.

5.

NRC No.93-102, "Final Policy Statement on Technical Specification Improvements," July 23, 1993.

6.

NRC Regulatory Guide 1.196, "Control Room Habitability At Light-Water Power Reactors," January, 2007.

7.

NEI 99-03, "Control Room Habitability Assessment," June, 2001.

8.

Letter from Eric J. Leeds (NRC) to James W. Davis (NEI) dated January 30, 2004, "NEI Draft White Paper, Use of Generic Letter 91-18 Process and Alternative Source Terms in the Context of Control Room Habitability,"

(ADAMS Accession No. ML040300694).

9.

FSAR, Chapter 10.12.5.3, Toxic Gas Protection.

10.

TVA Design Output Calculation NDQ0031920075, "Control Room and Offsite Doses Due to a LOCA," Revision 21.

BFN-UNIT 2 B 3.7-25a Amendment No. 255, 3Q2,

CREV System B 3.7.3 B 3.7 PLANT SYSTEMS B 3.7.3 Control Room Emergency Ventilation (CREV) System BASES BACKGROUND The CREV System provides a protected environment from occupants can control the unit following an uncontrolled release of radioactivity.

The safety related function of the CREV System includes two independent and redundant high efficiency air filtration subsystems for emergency treatment of outside supply air and a Control Room Envelope (CRE) boundary that limits the inleakage of unfiltered air. The CREV System has a high efficiency particulate air (HEPA) filter bank in the portion of the inlet piping common to both subsystems. Each CREV subsystem consists of a motor-driven fan, an electric duct air heater, an activated charcoal adsorber section, an electric charcoal heater, and the associated ductwork, valves or dampers, doors, barriers, and instrumentation. The HEPA filter bank removes particulate matter, which may be radioactive.

The charcoal adsorbers provide a holdup period for gaseous iodine, allowing time for decay; however, n credit is takn in tho aRnalyss for tho chrcoal adserbers.

The CRE is the area within the confines of the CRE boundary that contains the spaces that control room occupants inhabit to control the unit during normal and accident conditions. This area encompasses the control room, and may encompass other non-critical areas to which frequent personnel access or continuous occupancy is not necessary in the event of an accident. The CRE is protected during normal operation, natural event and accident conditions. The CRE boundary is the combination of walls, floors, roof, ducting, doors, penetrations and equipment that physically form the CRE. The OPERABILITY of the CRE boundary must be maintained to ensure that the inleakage of unfiltered air into the CRE will not (continued)

BFN-UNIT 3 B 3.7-17 Revision 0, 2-9 Amendment No. 264,

CREV System B 3.7.3 BASES BACKGROUND (continued) exceed the inleakage assumed in the licensing basis analysis of design basis accident (DBA) consequences to CRE occupants. The CRE and its boundary are defined in the Control Room Envelope Habitability Program.

Upon receipt of the initiation signal(s) (indicative of conditions that could result in radiation exposure to CRE occupants), the CREV System automatically switches to the pressurization mode of operation to minimize infiltration of contaminated air into the CRE. A system of dampers isolates the CRE. Outside air is taken in through the CREV System ventilation intake and is passed through one of the charcoal adsorber filter subsystems for removal of airborne radioactive particles.

The CREV System is designed to maintain a habitable environment in the CRE for a 30 day continuous occupancy after a DBA without exceeding 5 REM total effective dose equivalent (TEDE). A single CREV subsystem operating at a flow rate of 3000 cfm + 10 percent will pressurize the CRE to about 0.125 inches water gauge to minimize infiltration of air from all surrounding areas adjacent to CRE boundary and the outdoors. CREV System operation in maintaining CRE habitability is discussed in the FSAR, Section 10.12 (Ref. 1).

(continued)

BFN-UNIT 3 B 3.7-17a Revision 0, 2-9 Amendment No. 261 October 16, 2009

CREV System B 3.7.3 BASES (continued)

APPLICABLE SAFETY ANALYSIS The ability of the CREV System to maintain the habitability of the CRE is an explicit assumption for the safety analyses presented in the FSAR, Chapters 10 and 14 (Refs. 2 and 3, respectively). The pressurization mode of the CREV System is assumed to operate following a DBA, as discussed in the FSAR, Section 14.6 (Ref. 4). The analyses for radiological doses to CRE occupants as a result of the various DBAs are summarized in References 3 and 10. No credit is taken in the analyses for filtration by the HEPA filter or charcoal adsorbers. No single active failure will cause the loss of pressurization capability using fi1tede-outside air from the CRE.

There are no offsite or onsite hazardous chemicals that would pose a credible threat to CRE habitability (Ref 9). Consequently, engineering controls for the CRE are not required to ensure habitability against chemical threat.

The evaluation of a smoke challenge demonstrated that smoke will not result in the inability of the CRE occupants to control the reactor either from the control room or remote shutdown system (Ref 9).

The assessment verified that a fire or smoke event anywhere within the plant should not simultaneously render the remote shutdown system and the CRE uninhabitable, nor would it prevent access from the CRE to the remote shutdown system in the event remote shutdown is required. No automatic CREV actuation is required for hazardous chemical releases or smoke and no Surveillance Requirements are required to verify OPERABILITY in cases of hazardous chemicals or smoke.

The CREV System satisfies Criterion 3 of the NRC Policy Statement (Ref. 6).

(continued)

BFN-UNIT 3 B 3.7-18 Revision 0, 2-9 Amendment No. 264,

CREV System B 3.7.3 BASES (continued)

LCO Two redundant subsystems of the CREV System are required to be OPERABLE to ensure that at least one is available, if a single active failure, such as from a loss of both ventilation subsystems or from an inoperable CRE boundary, disables the other subsystem. Total system failure could result in exceeding a TEDE of 5 REM to the CRE occupants in the event of a DBA.

Each CREV subsystem is considered OPERABLE when the individual components necessary to limit CRE occupant exposure are OPERABLE. A subsystem is considered OPERABLE when its associated:

a. Fan is OPERABLE;

b. HEPA filter and charcoal adsorbers are not excessively restricting flow and are capable of performing their filtration functions; and

c. The electric duct heater, ductwork, and dampers are OPERABLE.

Charcoal adsorbers are considered OPERABLE when Ventilation Filter Testing Program (VFTP) acceptance criteria are met and the electric duct heater functions. The HEPA filter is considered OPERABLE when VFTP acceptance criteria are met.

In order for the CREV subsystems to be considered OPERABLE, the CRE boundary must be maintained such that the CRE occupant dose from a large radioactive release does not exceed the calculated dose in the licensing basis consequences analyses for DBAs, and that the CRE occupants are protected from hazardous chemicals and smoke.

BFN does not have automatic CREV actuations for hazardous chemicals or smoke. Current practices at BFN do not utilize.

(continued)

BFN-UNIT 3 B 3.7-19 Revision 0, 29 Amendment No. 244-, 264,

CREV System B 3.7.3 BASES LCO (continued) chemicals or sufficient quantity to present a chemical hazard to the CRE. Smoke is not considered in the current BFN safety analysis. Therefore, BFN has no specific limits on chemical hazards or smoke.

The LCO is modified by a Note allowing the CRE boundary to be opened intermittently under administrative controls. This Note only applies to openings in the CRE boundary that can be rapidly restored to the design condition such as doors, hatches, floor plugs, and access panels. For entry and exit through doors the administrative control of the opening is performed by the person(s) entering or exiting the area. For other openings, these controls should be proceduralized and consist of stationing a dedicated individual at the opening who is in continuous communication with the operators in the CRE. This individual will have a method to rapidly close the opening and to restore the CRE boundary to a condition equivalent to the design condition when a need for CRE isolation is indicated.

(continued)

BFN-UNIT 3 B 3.7-19a Revision 0, 2-9 Amendment No. 241-, 264-,

CREV System B 3.7.3 BASES (continued)

APPLICABILITY In MODES 1, 2, and 3, the CREV System must be OPERABLE to ensure that the CRE will remain habitable during and following a DBA, since the DBA could lead to a fission product release.

In MODES 4 and 5, the probability and consequences of a DBA are reduced because of the pressure and temperature limitations in these MODES. Therefore, maintaining the CREV System OPERABLE is not required in MODE 4 or 5, except for during operations with potential for draining the reactor vessel (OPDRVs).

ACTIONS A. 1 With one CREV subsystem inoperable, for reasons other than an inoperable CRE boundary, or inoperable HEPA filter or inoperable charcoal adsorbers (which do not impact the ability of the CREV subsystems to meet flowrate requirements specified in the VFTP), the inoperable CREV subsystem must be restored to OPERABLE status within 7 days. With the unit in this condition, the remaining OPERABLE CREV subsystem is adequate to perform the CRE occupant protection function.

However, the overall reliability is reduced because a failure in the OPERABLE subsystem could result in a loss of the CREV System function. The 7 day Completion Time is based on the low probability of a DBA occurring during this time period, and that the remaining subsystem can provide the required capabilities.

(continued)

BFN-UNIT 3 B 3.7-20 Revision 0, 2-9 Amendment

CREV System B 3.7.3 BASES ACTIONS B.1, B.2 and B.3 (continued)

If the unfiltered inleakage of potentially contaminated air past the CRE boundary and into the CRE can result in a CRE occupant radiological dose greater than the calculated dose of the licensing basis analyses of DBA consequences (allowed to be up to 5 REM TEDE) the CRE boundary is inoperable.

As discussed in the Applicable Safety Analysis Section, the BFN licensing bases notes that CRE inleakage limits for hazardous chemicals and smoke are not needed to protect the CRE occupants. Since the limit established for radiological events is limiting, verification of smoke and chemical hazards by administrative means is acceptable for an inoperable CRE boundary. Verification that the periodic check of onsite and offsite hazardous chemical sources has been performed within the time limit defined by the Control Room Habitability Program is an acceptable means to ensure the CRE occupants are protected from chemical hazards and smoke.

Actions must be taken to restore an OPERABLE CRE boundary within 90 days.

During the period that the CRE boundary is considered inoperable, action must be initiated to implement mitigating actions to lessen the effect on CRE occupants from the potential hazards of a radiological or chemical event or a challenge from smoke. Actions must be taken within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to verify that in the event of a DBA, the mitigating actions will ensure that CRE occupant radiological exposures will not exceed the calculated dose of the licensing basis analyses of DBA consequences and that CRE occupants are protected from hazardous chemicals and smoke. These mitigating actions (i.e., actions that are taken to offset the consequences of the inoperable CRE boundary) should be preplanned for implementation upon entry into the condition, regardless of whether entry is intentional or unintentional. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months (continued)

BFN-UNIT 3 B 3.7-21 Revision 0, 2-9 Amendment No. 244, 261 October 16, 2009

CREV System B 3.7.3 BASES ACTIONS B.1. B.2 and B.3 (continued)

Completion Time is reasonable based on the low probability of a DBA occurring during this time period and the use of mitigating actions. The 90 day Completion Time is reasonable based on the determination that the mitigating actions will ensure protection of CRE occupants within analyzed limits while limiting the probability that CRE occupants will have to implement protective measures that may adversely affect their ability to control the reactor and maintain it in a safe shutdown condition in the event of a DBA. In addition, the 90 day Completion Time is a reasonable time to diagnose, plan and possibly repair, and test most problems within the CRE boundary.

C.1 With two CREV subsystems inoperable due to a HEPA filter inoperable or both CREV subsystems' charcoal adsorbers inoperable, which do not impact the ability of the CREV subsystems to meet flowrate requirements specified in the VFTP, the HEPA filter and one of the charcoal adsorbers must be restored within 7 days. The 7 day Completion Time is based on the analysis for radiological dose to CRE occupants (Ref.

10), which has determined that the CRE 30 day dose after a DBA does not exceed 5 rem (TEDE) without credit for either the HEPA filter or the charcoal adsorbers.

D.1 With one CREV subsystem inoperable due to one inoperable charcoal adsorber, which does not impact the ability of the associated CREV subsystem to meet flowrate requirements specified in the VFTP, the charcoal adsorber must be restored within 14 days. The 14 day Completion Time is bases on the analysis for radiological dose to CRE occupants (Ref. 10), which has determined that the CRE 30 day dose after a DBA does not exceed 5 rem (TEDE) without credit for either (continued)

BFN-UNIT 3 B 3.7-21a Revision 0, 29 Amendment No. 241-, 26-1-,

CREV System B 3.7.3 BASES ACTIONS the HEPA filter or the charcoal adsorbers, and the capability of (continued) the remaining OPERABLE CREV subsystem.

EG.1 and EG.2 In MODE 1, 2, or 3, if the inoperable CREV subsystem(s) or the CRE cannot be restored to OPERABLE status within the required Completion Time, the unit must be placed in a MODE that minimizes accident risk. To achieve this status, the unit must be placed in at least MODE 3 within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and in MODE 4 within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The allowed Completion Times are reasonable, based on operating experience, to reach the required unit conditions from full power conditions in an orderly manner and without challenging unit systems.

FD.1 and F9.2 During OPDRVs, if the inoperable CREV subsystem cannot be restored to OPERABLE status within the required Completion Time, the OPERABLE CREV subsystem may be placed in the pressurization mode. This action ensures that the remaining subsystem is OPERABLE, that no failures that would prevent automatic actuation will occur, and that any active failure will be readily detected.

An alternative to Required Action FD.1 is to immediately initiate actions to suspend OPDRVs to minimize the probability of a vessel draindown and the subsequent potential for fission product release. Actions must continue until the OPDRVs are suspended.

(continued)

BFN-UNIT 3 B 3.7-22 Revision 0, 2-Amendment No. 241-, 2-64-,

CREV System B 3.7.3 BASES ACTIONS (continued)

GE. 1 If both CREV subsystems are inoperable in MODE 1, 2, or 3 for reasons other than an inoperable ORE (i.e., Condition B or Condition C), the CREV System may not be capable of performing the intended function and the unit is in a condition outside the accident analyses. Therefore, LCO 3.0.3 must be entered immediately.

HF.1 During OPDRVs, a) with two CREV subsystems inoperable for reasons other than an inoperable HEPA filter or inoperable charcoal adsorbers, b) er-with one or more CREV subsystems inoperable due to an inoperable CRE boundary, or c) if the HEPA filter and charcoal adsorbers can not be restored within the required Completion Time, actions must be initiated immediately to suspend OPDVRs to minimize the probability of a vessel draindown and subsequent potential for fission product release. Actions must continue until the OPDRVs are suspended.

(continued)

BFN-UNIT 3 B 3.7-23 Revision g, 2-Amendment No. 244-, 264,

CREV System B 3.7.3 BASES (continued)

SURVEILLANCE REQUIREMENTS SR 3.7.3.1 This SR verifies that a subsystem in a standby mode starts on demand and continues to operate. Standby systems should be checked periodically to ensure that they start and function properly. As the environmental and normal operating conditions of this system are not severe, testing each subsystem once every month provides an adequate check on this system.

Monthly heater operation dries out any moisture that has accumulated in the charcoal as a result of humidity in the ambient air. The CREV System must be operated for _> 10 continuous hours with.the heaters energized to dry out any moisture and to demonstrate the function of the system.

Furthermore, the 31 day Frequency is based on the known reliability of the equipment and the two subsystem redundancy available.

SR 3.7.3.2 This SR verifies that the required CREV testing is performed in accordance with the Ventilation Filter T,-ting PFrG*am (VFTP).

The VFTP includes testing HEPA filter performance, charcoal adsorber efficiency, minimum system flow rate, and the physical properties of the activated charcoal (general use and following specific operations). Specific test frequencies and additional information are discussed in detail in the VFTP.

(continued)

BFN-UNIT 3 B 3.7-24 Revision 0 Amendment

CREV System B 3.7.3 BASES SURVEILLANCE REQUIREMENTS (continued)

SR 3.7.3.3 This SR verifies that on an actual or simulated initiation signal, each CREV subsystem starts and operates. This SR includes verification that dampers necessary for proper CREV operation function as required. The LOGIC SYSTEM FUNCTIONAL TEST in SR 3.3.7.1.4 and SR 3.3.7.1.6 overlaps this SR to provide complete testing of the safety function. The frequency of 24 months is based on BFN's normal operating cycle.

SR 3.7.3.4 This SR verifies the OPERABILITY of the CRE boundary by testing for unfiltered air inleakage past the CRE boundary and into the CRE. The details of the testing are specified in the Control Room Envelope Habitability Program.

The CRE is considered habitable when the radiological dose to CRE occupants calculated in the licensing basis analyses of DBA consequences is no more that 5 REM TEDE and the CRE occupants are protected from hazardous chemicals and smoke.

There is no automatic CREV actuation for hazardous chemical releases or smoke and there are no Surveillance Requirements to verify the OPERABILITY in cases of hazardous chemicals or smoke. This SR verifies that the unfiltered air inleakage into the CRE is no greater than the flow rate assumed in the licensing basis analysis of DBA consequences. When unfiltered air inleakage is greater than the assumed flow rate, Condition B must be entered. Required Action B.3 allows time to restore the CRE boundary to OPERABLE status provided mitigating actions can ensure that the CRE remains within the licensing basis habitability limits for occupants following an accident.

Compensatory measures are discussed in Regulatory Guide 1.196, Section C.2.7.3, (Ref. 6) which endorses, with exceptions, NEI 99-03, Section 8.4 and Appendix F (Ref. 7).

These compensatory measures may also be used as mitigating actions as required by Required Action B.2. Temporary analytical methods may also be used as compensatory (continued)

BFN-UNIT 3 B 3.7-25 Amendment No. 24-6, 261 October 16, 2009

CREV System B 3.7.3 BASES SURVEILLANCE SR 3.7.3.4 (continued)

REQUIREMENTS measures to restore OPERABILITY (Ref. 8). Options for restoring the CRE boundary to OPERABLE status include changing the licensing basis DBA consequences analysis, repairing the CRE boundary, or a combination of these actions.

Depending upon the nature of the problem and the corrective action, a full scope inleakage test may not be necessary to establish that the CRE boundary has been restored to OPERABLE status.

REFERENCES

1.

FSAR, Section 10.12.

2.

FSAR, Chapter 10.

3.

FSAR, Chapter 14.

4.

FSAR, Section 14.6.

5.

NRC No.93-102, "Final Policy Statement on Technical Specification Improvements," July 23, 1993.

6.

NRC Regulatory Guide 1.196, "Control Room Habitability At Light-Water Power Reactors," January 2007.

7.

NEI 99-03, "Control Room Habitability Assessment," June 2001.

8.

Letter from Eric J. Leeds (NRC) to James W. David (NEI) dated January 30, 2004, "NEI Draft White Paper, Use of Generic Letter 91-18 Process and Alternative Source Terms in the Context of Control Room Habitability,"

(ADAMS Accession No. ML040300694).

9.

FSAR, Chapter 10.12.5.3, Toxic Gas Protection.

10.

TVA Design Output Calculation NDQ0031920075, "Control Room and Offsite Doses Due to LOCA," Revision 21.

BFN-UNIT 3 B 3.7-25a Amendment No. 2-1-5, 26-1-,

Browns Ferry Nuclear Plant (BFN), Units 1, 2, and 3 Technical Specifications (TS) Change 474 License Amendment Request to Add a TS 3.7.3, "Control Room Emergency Ventilation (CREV) System," Action to Address Inoperable CREV High Efficiency Particulate Air (HEPA) Filter and/or Charcoal Adsorbers Proposed Technical Specifications Pages - Retyped

CREV System 3.7.3 3.7 PLANT SYSTEMS 3.7,3 Control Room Emergency Ventilation (CREV) System LCO 3.7.3 Two CREV subsystems shall be OPERABLE.

kinTI:

IIU The main control room envelope (CRE) boundary may be opened intermittently under administrative control.

APPLICABILITY:

MODES 1, 2, and 3, during operations with a potential for draining the reactor vessel (OPDRVs).

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One CREV subsystem A.1 Restore CREV subsystem 7 days inoperable for reasons to OPERABLE status.

other than Condition B, C, or D.

B. One or more CREV B.1 Initiate action to Immediately subsystems inoperable implement mitigating due to inoperable CRE actions boundary in MODE 1, 2, or 3.

AND B.2 Verify mitigating actions 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months ensure CRE occupant exposures to radiological hazards will not exceed limits, and verify the CRE occupants are protected from smoke and chemical hazards.

AND B.3 Restore CRE boundary to 90 days OPERABLE status.

(continued)

BFN-UNIT 1 3.7-8 Amendment No. 2-46, 254, 2-7-5,

CREV System 3.7.3 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME C. Two CREV subsystems C.1 Restore HEPA filter and 7 days inoperable due to one charcoal adsorber to inoperable High Efficiency OPERABLE status.

Particulate Air (HEPA) filter or charcoal adsorbers which do not impact ability of CREV subsystems to meet flowrate requirements specified in the Ventilation Filter Testing Program (VFTP).

D. One CREV subsystem D.1 Restore charcoal 14 days inoperable due to adsorber to OPERABLE inoperable charcoal status.

adsorber which does not impact the ability of CREV subsystem to meet flowrate requirements specified in the VFTP.

E. Required Action and E.1 Be in MODE 3.

12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months associated Completion Time of Condition A, B, C, AND or D not met in MODE 1, 2, or 3.

E.2 Be in MODE 4.

36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months (continued)

BFN-UNIT 1 3.7-8a Amendment No. 246, 25I, 2-7-5,

CREV System 3.7.3 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME F. Required Action and F.1 Place OPERABLE CREV Immediately associated Completion subsystem in Time of Condition A or D pressurization mode.

not met during OPDRVs.

OR F.2 Initiate action to suspend Immediately OPDRVs.

G. Two CREV subsystems G.1 Enter LCO 3.0.3.

Immediately inoperable in MODE 1, 2, or 3 for reasons other than Condition B or C.

(continued)

BFN-UNIT 1 3.7-9 Amendment No. 2-34, 246, 241-,

CREV System 3.7.3 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME H. Required Action and H.1 Initiate action to suspend Immediately associated Completion OPDRVs.

Time of Condition C not met during OPDRVs.

OR Two CREV subsystems inoperable during OPDRVs for reasons other than Condition C.

OR One or more CREV subsystems inoperable due to an inoperable CRE Boundary during OPDRVs.

BFN-UNIT 1 3.7-10 Amendment No. 2-46, 2-54, 2-7-5,

CREV System 3.7.3 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.3.1 Operate each CREV subsystem for _> 10 31 days continuous hours with the heaters operating.

SR 3.7.3.2 Perform required CREV filter testing in In accordance accordance with the VFTP.

with the VFTP SR 3.7.3.3 Verify each CREV subsystem actuates on an 24 months actual or simulated initiation signal.

SR 3.7.3.4 Perform required CRE unfiltered air inleakage In accordance testing in accordance with the Control Room with the Control Envelope Habitability Program.

Room Envelope Habitability Program BFN-UNIT 1 3.7-11 Amendment No. 235, 27-5,

CREV System 3.7.3 3.7 PLANT SYSTEMS 3.7.3 Control Room Emergency Ventilation (CREV) System LCO 3.7.3 Two CREV subsystems shall be OPERABLE.

NOTE The main control room envelope (CRE) boundary may be opened intermittently under administrative control.

APPLICABILITY:

MODES 1, 2, and 3, during operations with a potential for draining the reactor vessel (OPDRVs).

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One CREV subsystem A.1 Restore CREV subsystem 7 days inoperable for reasons to OPERABLE status.

other than Condition B, C, or D.

B. One or more CREV B.1 Initiate actions to Immediately subsystems inoperable implement mitigating due to inoperable CRE actions.

boundary in MODE 1, 2, or 3.

AND B.2 Verify mitigating actions 24 Hours ensure CRE occupant exposures to radiological hazards will not exceed limits, and verify the CRE occupants are protected from smoke and chemical hazards.

AND B.3 Restore CRE boundary to 90 days OPERABLE status.

(continued)

BFN-UNIT 2 3.7-9 Amendment No. 2-8, 290, 302,

CREV System 3.7.3 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME C. Two CREV subsystems C.1 Restore HEPA filter and 7 days inoperable due to one charcoal adsorber to inoperable High Efficiency OPERABLE status.

Particulate Air (HEPA) filter or charcoal adsorbers which do not impact ability of CREV subsystems to meet flowrate requirements specified in the Ventilation Filter Testing Program (VFTP).

D. One CREV subsystem D.1 Restore charcoal 14 days inoperable due to adsorber to OPERABLE inoperable charcoal status.

adsorber which does not impact the ability of CREV subsystem to meet flowrate requirements specified in the VFTP.

E. Required Action and E.1 Be in MODE 3.

12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months associated Completion Time of Condition A, B, C, AND or D not met in MODE 1, 2, or 3.

E.2 Be in MODE 4.

36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months (continued)

BFN-UNIT 2 3.7-9a Amendment No. 28W, 2-9, 302,

CREV System 3.7.3 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME F. Required Action and F.1 Place OPERABLE CREV Immediately associated Completion subsystem in Time of Condition A or D pressurization mode.

not met during OPDRVs.

OR F.2 Initiate action to suspend Immediately OPDRVs.

G. Two CREV subsystems G.1 Enter LCO 3.0.3.

Immediately inoperable in MODE 1, 2, or 3 for reasons other than Condition B or C.

(continued)

BFN-UNIT 2 3.7-10 Amendment No. 2-54, 2-82, 2-9,

CREV System 3.7.3 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME H. Required Action and H.1 Initiate action to suspend Immediately associated Completion OPDRVs.

Time of Condition C not met during OPDRVs OR Two CREV subsystems inoperable during OPDRVs for reasons other than Condition C.

OR One or more CREV subsystems inoperable due to an inoperable CRE Boundary during OPDRVs.

BFN-UNIT 2 3.7-11 Amendment No. 2483, 2GG, 3G2,

CREV System 3.7.3 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.3.1 Operate each CREV subsystem for _> 10 31 days continuous hours with the heaters operating.

SR 3.7.3.2 Perform required CREV filter testing in In accordance accordance with the VFTP.

with the VFTP SR 3.7.3.3 Verify each CREV subsystem actuates on an 24 months actual or simulated initiation signal.

SR 3.7.3.4 Perform required CRE unfiltered air inleakage In accordance testing in accordance with the Control Room with the Control Envelope Habitability Program.

Room Envelope Habitability Program BFN-UNIT 2 3.7-12 Amendment No. 245, W2,

CREV System 3.7.3 3.7 PLANT SYSTEMS 3.7.3 Control Room Emergency Ventilation (CREV) System LCO 3.7.3 Two CREV subsystems shall be OPERABLE.

NOTE The main control room envelope (CRE) boundary may be opened intermittently under administrative control.

APPLICABILITY:

MODES 1, 2, and 3, during operations with a potential for draining the reactor vessel (OPDRVs).

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One CREV subsystem A.1 Restore CREV subsystem 7 days inoperable for reasons to OPERABLE status.

other than Condition B, C, or D.

B. One or more CREV B.1 Initiate actions to Immediately subsystems inoperable implement mitigating due to inoperable CRE actions.

boundary in MODE 1, 2, or 3.

AND B.2 Verify mitigating actions 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months ensure CRE occupant exposures to radiological hazards will not exceed limits, and verify the CRE occupants are protected from smoke and chemical hazards.

AND B.3 Restore CRE boundary to 90 days OPERABLE status.

(continued)

BFN-UNIT 3 3.7-9 Amendment No. 241-, 24-, 2-64-,

CREV System 3.7.3 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME C. Two CREV subsystems C.1 Restore HEPA filter and 7 days inoperable due to one charcoal adsorber to inoperable High Efficiency OPERABLE status.

Particulate Air (HEPA) filter or charcoal adsorbers which do not impact ability of CREV subsystems to meet flowrate requirements specified in the Ventilation Filter Testing Program (VFTP).

D. One CREV subsystem D.1 Restore charcoal 14 days inoperable due to adsorber to OPERABLE inoperable charcoal status.

adsorber which does not impact the ability of CREV subsystem to meet flowrate requirements specified in the VFTP.

E. Required Action and E.1 Be in MODE 3.

12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months associated Completion Time of Condition A, B, C, AND or D not met in MODE 1, 2, or 3.

E.2 Be in MODE 4.

36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months (continued)

BFN-UNIT 3 3.7-9a Amendment No. 244-, 249, 26-1-,

CREV System 3.7.3 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME F. Required Action and F.1 Place OPERABLE CREV Immediately associated Completion subsystem in Time of Condition A or D pressurization mode.

not met during OPDRVs.

OR F.2 Initiate action to suspend Immediately OPDRVs.

G. Two CREV subsystems G.1 Enter LCO 3.0.3.

Immediately inoperable in MODE 1, 2, or 3 for reasons other than Condition B or C.

(continued)

BFN-UNIT 3 3.7-10 Amendment No. 244, 244-, 249,

CREV System 3.7.3 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME H. Required Action and H.1 Initiate action to suspend Immediately associated Completion OPDRVs.

Time of Condition C not met during OPDRVs.

OR Two CREV subsystems inoperable during OPDRVs for reasons other than Condition C.

OR One or more CREV subsystems inoperable due to an inoperable CRE Boundary during OPDRVs.

BFN-UNIT 3 3.7-11 Amendment No. 241-, 249, 26-1-,

CREV System 3.7.3 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.3.1 Operate each CREV subsystem for __ 10 31 days continuous hours with the heaters operating.

SR 3.7.3.2 Perform required CREV filter testing in In accordance accordance with the VFTP.

with the VFTP SR 3.7.3.3 Verify each CREV subsystem actuates on an 24 months actual or simulated initiation signal.

SR 3.7.3.4 Perform required CRE unfiltered air inleakage In accordance testing in accordance with the Control Room with the Control Envelope Habitability Program.

Room Envelope Habitability Program BFN-UNIT 3 3.7-12 Amendment No. 2-1-5, 26-1-,

Browns Ferry Nuclear Plant (BFN), Units 1, 2, and 3 Technical Specifications (TS) Change 474 License Amendment Request to Add a TS 3.7.3, "Control Room Emergency Ventilation (CREV) System," Action to Address Inoperable CREV High Efficiency Particulate Air (HEPA) Filter and/or Charcoal Adsorbers Proposed Technical Specifications Bases Pages - Retyped

CREV System B 3.7.3 B 3.7 PLANT SYSTEMS B 3.7.3 Control Room Emergency Ventilation (CREV) System BASES BACKGROUND The CREV System provides a protected environment from which occupants can control the unit following an uncontrolled release of radioactivity.

The safety related function of the CREV System includes two independent and redundant high efficiency air filtration subsystems for emergency treatment of outside supply air and a Control Room Envelope (CRE) boundary that limits the inleakage of unfiltered air. The CREV System has a high efficiency particulate air (HEPA) filter bank in the portion of the inlet piping common to both subsystems. Each CREV subsystem consists of a motor-driven fan, an electric duct air heater, an activated charcoal adsorber section, an electric charcoal heater, and the associated ductwork, valves or dampers, doors, barriers, and instrumentation. The HEPA filter bank removes particulate matter, which may be radioactive.

The charcoal adsorbers provide a holdup period for gaseous iodine, allowing time for decay.

The CRE is the area within the confines of the CRE boundary that contains the spaces that control room occupants inhabit to control the unit during normal and accident conditions. This area encompasses the control room, and may encompass other non-critical areas to which frequent personnel access or continuous occupancy is not necessary in the event of an accident. The CRE is protected during normal operation, natural event and accident conditions. The CRE boundary is the combination of walls, floor, roof, ducting, doors, penetrations and equipment that physically form the CRE. The OPERABILITY of the CRE boundary must be (continued)

BFN-UNIT 1 B 3.7-17 Revision 0,-2-9 Amendment 2-7-5,

CREV System B 3.7.3 BASES BACKGROUND (continued) maintained to ensure that the inleakage of unfiltered air into the CRE will not exceed the inleakage assumed in the licensing basis analysis of design basis accident (DBA) consequences to CRE occupants. The CRE and its boundary are defined in the Control Room Envelope Habitability Program.

Upon receipt of the initiation signal(s) (indicative of conditions that could result in radiation exposure to CRE occupants), the CREV System automatically switches to the pressurization mode of operation to minimize infiltration of contaminated air into the CRE. A system of dampers isolates the CRE. Outside air is taken in through the CREV System ventilation intake and is passed through one of the charcoal adsorber filter subsystems for removal of airborne radioactive particles.

The CREV System is designed to maintain a habitable environment in the CRE for 30 day continuous occupancy after a DBA without exceeding 5 REM total effective dose equivalent (TEDE). A single CREV subsystem operating at a flow of 3000 cfm +/-10 percent will pressurize the CRE to about 0.125 inches water gauge to minimize infiltration of air from all surrounding areas adjacent to CRE boundary and the outdoors. CREV System operation in maintaining CRE habitability is discussed in the FSAR, Section 10.12 (Ref. 1).

APPLICABLE SAFETY ANALYSES The ability of the CREV System to maintain the habitability of the CRE is an explicit assumption for the safety analyses presented in the FSAR, Chapters 10 and 14 (Refs. 2 and 3, respectively). The pressurization mode of the CREV System is assumed to operate following a DBA, as discussed in the FSAR, Section 14.6 (Ref. 4). The analyses for radiological doses to CRE occupants as a result of the various DBAs are summarized in References 3 and 10. No credit is taken in the analysis for filtration by the HEPA filter or charcoal adsorbers.

(continued)

BFN-UNIT 1 B 3.7-18 Revision 0, 29 Amendment 2-7-5,

CREV System B 3.7.3 BASES APPLICABLE No single active failure will cause the loss of pressurization SAFETY ANALYSIS capability using outside air from the CRE.

(continued)

There are no offsite or onsite hazardous chemicals that would pose a credible threat to CRE habitability (Ref 9).

Consequently, engineering controls for the CRE are not required to ensure habitability against chemical threat.

The evaluation of a smoke challenge demonstrated that smoke will not result in the inability of the CRE occupants to control the reactor either from the control room or remote shutdown system (Ref 9). The assessment verified that a fire or smoke event anywhere within the plant should not simultaneously render the remote shutdown system and the CRE uninhabitable, nor would it prevent access from the CRE to the remote shutdown system in the event remote shutdown is required. No automatic CREV actuation is required for hazardous chemical releases or smoke and no Surveillance Requirements are required to verify OPERABILITY in cases of hazardous chemicals or smoke.

The CREV System satisfies Criterion 3 of the NRC Policy Statement (Ref. 6).

(continued)

BFN-UNIT 1 B 3.7-18a Revision Q, 2-9 Amendment 2-7-5,

CREV System B 3.7.3 BASES (continued)

LCO Two redundant subsystems of the CREV System are required to be OPERABLE to ensure that at least one is available, if a single active failure disables the other subsystem. Total CREV System failure, such as from a loss of both ventilation subsystems or from an inoperable CRE boundary, could result in exceeding a TEDE of 5 REM to the CRE occupants in the event of a DBA.

Each CREV subsystem is considered OPERABLE when the individual components necessary to limit CRE occupant exposure are OPERABLE. A subsystem is considered OPERABLE when its associated:

a. Fan is OPERABLE;

b. HEPA filter and charcoal adsorbers are not excessively restricting flow and are capable of performing their filtration functions; and

c. The electric duct heater, ductwork, and dampers are OPERABLE.

Charcoal adsorbers are considered OPERABLE when Ventilation Filter Testing Program (VFTP) acceptance criteria are met and the electric duct heater functions to support the charcoal adsorber function. The HEPA filter is considered OPERABLE when VFTP acceptance criteria are met.

In order for the CREV subsystems to be considered OPERABLE, the CRE boundary must be maintained such that the CRE occupant dose from a large radioactive release does not exceed the calculated dose in the licensing basis consequences analyses for DBAs, and that the CRE occupants are protected from hazardous chemicals and smoke.

BFN does not have automatic CREV actuations for hazardous chemicals or smoke. Current practices at BFN do not utilize (continued)

BFN-UNIT 1 B 3.7-19 Revision Q, 2-9 Amendment 2-7-5,

CREV System B 3.7.3 BASES LCO (continued) chemicals of sufficient quantity to present a chemical hazard to the CRE. Smoke is not considered in the current BFN safety analysis. Therefore, BFN has no specific limits on chemical hazards or smoke.

The LCO is modified by a Note allowing the CRE boundary to be opened intermittently under administrative controls. This Note only applies to openings in the CRE boundary that can be rapidly restored to the design condition, such as doors, hatches, floor plugs, and access panels. For entry and exit through doors the administrative control of the opening is performed by the person(s) entering or exiting the area. For other openings, these controls should be proceduralized and consist of stationing a dedicated individual at the opening who is in continuous communication with the operators in the CRE.

This individual will have a method to rapidly close the opening and to restore the CRE boundary to a condition equivalent to the design condition when a need for CRE isolation is indicated.

(continued)

BFN-UNIT 1 B 3.7-19a Revision -, 2-9 Amendment 27-5,

CREV System B 3.7.3 BASES (continued)

APPLICABILITY In MODES 1, 2, and 3, the CREV System must be OPERABLE to ensure that the CRE will remain habitable during and following a DBA, since the DBA could lead to a fission product release.

In MODES 4 and 5, the probability and consequences of a DBA are reduced because of the pressure and temperature limitations in these MODES. Therefore, maintaining the CREV System OPERABLE is not required in MODE 4 or 5, except for during operations with potential for draining the reactor vessel (OPDRVs).

ACTIONS A. 1 With one CREV subsystem inoperable, for reasons other than an inoperable CRE boundary, or inoperable HEPA filter or inoperable charcoal adsorbers (which do not impact the ability of the CREV subsystems to meet flowrate requirements specified in the VFTP), the inoperable CREV subsystem must be restored to OPERABLE status within 7 days. With the unit in this condition, the remaining OPERABLE CREV subsystem is adequate to perform the CRE occupant protection function.

However, the overall reliability is reduced because a failure in the OPERABLE subsystem could result in loss of the CREV System function. The 7 day Completion Time is based on the low probability of a DBA occurring during this time period, and that the remaining subsystem can provide the required capabilities.

(continued)

BFN-UNIT 1 B 3.7-20 Revision 0, 2-Amendment No. 246, 27-5,

CREV System B 3.7.3 BASES ACTIONS B.1, B2 and B3 (continued)

If the unfiltered inleakage of potentially contaminated air past the CRE boundary and into the CRE can result in a CRE occupant radiological dose greater than the calculated dose of the licensing basis analyses of DBA consequences (allowed to be up to 5 REM TEDE) the CRE boundary is inoperable.

As discussed in the Applicable Safety Analysis Section, the BFN licensing bases notes that CRE inleakage limits for hazardous chemicals and smoke are not needed to protect the CRE occupants. Since the limit established for radiological events is limiting, verification of smoke and chemical hazards by administrative means is acceptable for an inoperable CRE boundary. Verification that the periodic check of onsite and offsite hazardous chemical sources has been performed within the time limit defined by the Control Room Habitability Program is an acceptable means to ensure the CRE occupants are protected from chemical hazards and smoke.

Actions must be taken to restore an OPERABLE CRE boundary within 90 days.

During the period that the CRE boundary is considered inoperable, action must be initiated to implement mitigating actions to lessen the effect on CRE occupants from the potential hazards of a radiological or chemical event or a challenge from smoke. Actions must be taken within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to verify that in the event of a DBA, the mitigating actions will ensure that CRE occupant radiological exposures will not exceed the calculated dose of the licensing basis analyses of DBA consequences and that CRE occupants are protected from hazardous chemicals and smoke. These mitigating actions (i.e., actions that are taken to offset the consequences of the inoperable CRE boundary) should be preplanned for implementation upon entry into the condition, regardless of whether entry is intentional or unintentional. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months (continued)

BFN-UNIT 1 B 3.7-21 Revision Q, 2-9 Amendment No.-246, 275 October 16, 2009

CREV System B 3.7.3 BASES ACTIONS B.1, B2 and B3 (continued)

Completion Time is reasonable based on low probability of a DBA occurring during this time period and the use of mitigating actions. The 90 day Completion Time is reasonable based on the determination that the mitigating actions will ensure protection of CRE occupants within analyzed limits while limiting the probability that CRE occupants will have to implement protective measures that may adversely affect their ability to control the reactor and maintain it in a safe shutdown condition in the event of a DBA. In addition, the 90 day Completion Time is a reasonable time to diagnose, plan and possibly repair, and test most problems within the CRE boundary.

C.1 With two CREV subsystems inoperable due to a HEPA filter inoperable or both CREV subsystems' charcoal adsorbers inoperable, which do not impact the ability of the CREV subsystems to meet flowrate requirements specified in the VFTP, the HEPA filter and one of the charcoal adsorbers must be restored within 7 days. The 7 day Completion Time is based on the analysis for radiological dose to CRE occupants (Ref. 10), which has determined that the CRE 30 day dose after a DBA does not exceed 5 rem (TEDE) without credit for either the HEPA filter or the charcoal adsorbers.

D.1 With one CREV subsystem inoperable due to one inoperable charcoal adsorber, which does not impact the ability of the associated CREV subsystem to meet flowrate requirements specified in the VFTP, the charcoal adsorber must be restored within 14 days. The 14 day Completion Time is based on the analysis for radiological dose to CRE occupants (Ref. 10), which has determined that the CRE 30 day dose after a DBA does not exceed 5 rem (TEDE) without credit for either (continued)

BFN-UNIT 1 B 3.7-21a Revision Q, 2-9 Amendment No.-246, 2-7-5,

CREV System B 3.7.3 BASES ACTIONS the HEPA filter or the charcoal adsorbers, and the capability of (continued) the remaining OPERABLE CREV subsystem.

E.1 and E.2 In MODE 1, 2, or 3, if the inoperable CREV subsystem(s) or the CRE boundary cannot be restored to OPERABLE status within the required Completion Time, the unit must be placed in a MODE that minimizes accident risk. To achieve this status, the unit must be placed in at least MODE 3 within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and in MODE 4 within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The allowed Completion Times are reasonable, based on operating experience, to reach the required unit conditions from full power conditions in an orderly manner and without challenging unit systems.

F.1 and F.2 During OPDRVs, if the inoperable CREV subsystem cannot be restored to OPERABLE status within the required Completion Time, the OPERABLE CREV subsystem may be placed in the pressurization mode. This action ensures that the remaining subsystem is OPERABLE, that no failures that would prevent automatic actuation will occur, and that any active failure will be readily detected.

An alternative to Required Action F.1 is to immediately initiate actions to suspend OPDRVs to minimize the probability of a vessel draindown and the subsequent potential for fission product release. Actions must continue until the OPDRVs are suspended.

(continued)

BFN-UNIT I B 3.7-22 Revision 0-, 2-9 Amendment No.-246, 2-7-5,

CREV System B 3.7.3 BASES ACTIONS (continued)

G..1 If both CREV subsystems are inoperable in MODE 1, 2, or 3 for reasons other than Condition B or Condition C, the CREV System may not be capable of performing the intended function and the unit is in a condition outside the accident analyses.

Therefore, LCO 3.0.3 must be entered immediately.

H.1 During OPDRVs, a) with two CREV subsystems inoperable for reasons other than an inoperable HEPA filter or inoperable charcoal adsorbers, b) with one or more CREV subsystems inoperable due to an inoperable CRE boundary, or c) if the HEPA filter and charcoal adsorbers can not be restored to OPERABLE status within the required Completion Time, actions must be initiated immediately to suspend OPDVRs to minimize the probability of a vessel draindown and subsequent potential for fission product release. Actions must continue until the OPDRVs are suspended.

(continued)

BFN-UNIT 1 B 3.7-23 Revision Q-, 2-9 Amendment No. 246, 2-7-5,

CREV System B 3.7.3 BASES (continued)

SURVEILLANCE SR 3.7.3.1 REQUIREMENTS This SR verifies that a subsystem in a standby mode starts on demand and continues to operate. Standby systems should be checked periodically to ensure that they start and function properly. As the environmental and normal operating conditions of this system are not severe, testing each subsystem once every month provides an adequate check on this system.

Monthly heater operation dries out any moisture that has accumulated in the charcoal as a result of humidity in the ambient air. The CREV System must be operated for > 10 continuous hours with the heaters energized to dry out any moisture and to demonstrate the function of the system.

Furthermore, the 31 day Frequency is based on the known reliability of the equipment and the two subsystem redundancy available.

SR 3.7.3.2 This SR verifies that the required CREV testing is performed in accordance with the VFTP. The VFTP includes testing HEPA filter performance, charcoal adsorber efficiency, minimum system flow rate, and the physical properties of the activated charcoal (general use and following specific operations).

Specific test frequencies and additional information are discussed in detail in the VFTP.

(continued)

BFN-UNIT 1 B 3.7-24 Revision 0

CREV System B 3.7.3 BASES SURVEILLANCE REQUIREMENTS (continued)

SR 3.7.3.3 This SR verifies that on an actual or simulated initiation signal, each CREV subsystem starts and operates. This SR includes verification that dampers necessary for proper CREV operation function as required. The LOGIC SYSTEM FUNCTIONAL TEST in SR 3.3.7.1.4 and SR 3.3.7.1.6 overlaps this SR to provide complete testing of the safety function. The Frequency of 24 months is based on BFN's normal operating cycle.

SR 3.7.3.4 This SR verifies the OPERABILITY of the CRE boundary by testing for unfiltered air inleakage past the CRE boundary and into the CRE. The details of the testing are specified in the Control Room Envelope Habitability Program.

The CRE is considered habitable when the radiological dose to CRE occupants calculated in the licensing basis analyses of DBA consequences is no more that 5 REM TEDE and the CRE occupants are protected from hazardous chemicals and smoke.

There is no automatic CREV actuation for hazardous chemical releases or smoke and there are no Surveillance Requirements to verify the OPERABILITY in cases of hazardous chemicals or smoke. This SR verifies that the unfiltered air inleakage into the CRE is no greater than the flow rate assumed in the licensing basis analysis of DBA consequences. When unfiltered air inleakage is greater than the assumed flow rate, Condition B must be entered. Required Action B.3 allows time to restore the CRE boundary to OPERABLE status provided mitigating actions can ensure that the CRE remains within the licensing basis habitability limits for occupants following an accident.

Compensatory measures are discussed in Regulatory Guide 1.196, Section C.2.7.3, (Ref. 6) which endorses, with exceptions, NEI 99-03, Section 8.4 and Appendix F (Ref. 7).

These compensatory measures may also be used as mitigating actions as required by Required Action B.2. Temporary analytical methods may also be used as compensatory (continued)

BFN-UNIT 1 B 3.7-25 Amendment No. 2-3, 275 October 16, 2009

CREV System B 3.7.3 BASES SURVEILLANCE REQUIREMENTS SR 3.7.3.4 (continued) measures to restore OPERABILITY (Ref. 8). Options for restoring the CRE boundary to OPERABLE status include changing the licensing basis DBA consequences analysis, repairing the CRE boundary, or a combination of these actions.

Depending upon the nature of the problem and the corrective action, a full scope inleakage test may not be necessary to establish that the CRE boundary has been restored to OPERABLE status.

(continued)

BFN-UNIT 1 B 3.7-25a Amendment No. 2-,6, 275 October 16, 2009

CREV System B 3.7.3 BASES (continued)

REFERENCES

1. FSAR, Section 10.12.

2. FSAR, Chapter 10.

3. FSAR, Chapter 14.

4. FSAR, Section 14.6.

5. NRC No.93-102, "Final Policy Statement on Technical Specification Improvements," July 23, 1993.

6. NRC Regulatory Guide 1.196, "Control Room Habitability At Light-Water Power Reactors," January 2007.

7. NEI 99-03, "Control Room Habitability Assessment," June 2001.

8. Letter from Eric J. Leeds (NRC) to James W. Davis (NEI) dated January 30, 2004, "NEI Draft White Paper, Use of Generic Letter 91-18 Process and Alternative Source Terms in the Context of Control Room Habitability," (ADAMS Accession No. ML040300694).

9. FSAR, Chapter 10.12.5.3, Toxic Gas Protection.

10. TVA Design Output Calculation NDQ0031920075, "Control Room and Offsite Dose Due to a LOCA," Revision 21.

BFN-UNIT 1 B 3.7-25b Amendment No. 235, 2-7-5,

CREV System B 3.7.3 B 3.7 PLANT SYSTEMS B 3.7.3 Control Room Emergency Ventilation (CREV) System BASES BACKGROUND The CREV System provides a protected environment from which occupants can control the unit following an uncontrolled release of radioactivity.

The safety related function of the CREV System includes two independent and redundant high efficiency air filtration subsystems for emergency treatment of outside supply air and a Control Room Envelope (CRE) boundary that limits the inleakage of unfiltered air. The CREV System has a high efficiency particulate air (HEPA) filter bank in the portion of the inlet piping common to both subsystems. Each CREV subsystem consists of a motor-driven fan, an electric duct air heater, an activated charcoal adsorber section, an electric charcoal heater, and the associated ductwork, valves or dampers, doors, barriers and instrumentation. The HEPA filter bank removes particulate matter, which may be radioactive.

The charcoal adsorbers provide a holdup period for gaseous iodine, allowing time for decay.

The CRE is the areas within the confines of the CRE boundary that contains the spaces that control room occupants inhabit to control the unit during normal and accident conditions. This area encompasses the control room, and may encompass other non-critical areas to which frequent personnel access or continuous occupancy is not necessary in the event of an accident. The CRE is protected during normal operation, natural event and accident conditions. The CRE boundary is the combination of wall, floor, root, ducting, doors, penetrations and equipment that physically form the CRE. The OPERABILITY of the CRE boundary must be maintained to ensure that the inleakage of unfiltered air in the CRE will not (continued)

BFN-UNIT 2 B 3.7-17 Revision G, 2-9 Amendment No. W2,

CREV System B 3.7.3 BASES BACKGROUND (continued) exceed the inleakage assumed in the licensing basis analysis of design basis accident (DBA) consequences to CRE occupants. The CRE and its boundary are defined in the Control Room Envelope Habitability Program.

Upon receipt of the initiation signal(s) (indicative of conditions that could result in radiation exposure to CRE occupants), the CREV System automatically switches to the pressurization mode of operation to minimize infiltration of contaminated air into the CRE. A system of dampers isolates the CRE. Outside air is taken in through the CREV System ventilation intake and is passed through one of the charcoal adsorber filter subsystems for removal of airborne radioactive particles.

The CREV System is designed to maintain a habitable environment in the CRE for a 30 day continuous occupancy after a DBA without exceeding 5 REM total effective dose equivalent (TEDE). A single CREV subsystem operating at a flow rate of 3000 CFM + 10 percent will pressurize the CRE to about 0.125 inches water gauge to minimize infiltration of air from all surrounding areas adjacent to CRE boundary and the outdoors. CREV System operation in maintaining CRE habitability is discussed in the FSAR, Section 10.12 (Ref. 1).

(continued)

BFN-UNIT 2 B 3.7-17a Revision G, 2-9 Amendment No. 302 October 16, 2009

CREV System B 3.7.3 BASES (continued)

APPLICABLE SAFETY ANALYSES The ability of the CREV System to maintain the habitability of the CRE is an explicit assumption for the safety analyses presented in the FSAR, Chapters 10 and 14 (Refs. 2 and 3, respectively). The pressurization mode of the CREV System is assumed to operate following a DBA, as discussed in the FSAR, Section 14.6 (Ref. 4). The analyses for radiological doses to CRE occupants as a result of the various DBAs are summarized in References 3 and 10. No credit is taken in the analyses for filtration by the HEPA filter or charcoal adsorbers. No single active failure will cause the loss of pressurization capability using outside air from the CRE.

There are no offsite or onsite hazardous chemicals that would pose a credible threat to CRE habitability (Ref. 9).

Consequently, engineering controls for the CRE are not required to ensure habitability against chemical threat.

The evaluation of a smoke challenge demonstrated that smoke will not result in the inability of the CRE occupants to control the reactor either from the control room or remote shutdown system (Ref 9). The assessment verified that a fire or smoke event anywhere within the plant should not simultaneously render the remote shutdown system and the CRE uninhabitable, nor would it prevent access from the CRE to the remote shutdown system in the event remote shutdown is required. No automatic CREV actuation is required for hazardous chemical releases or smoke and no Surveillance Requirements are required to verify OPERABILITY in cases of hazardous chemicals or smoke.

The CREV System satisfies Criterion 3 of the NRC Policy Statement (Ref. 6).

(continued)

BFN-UNIT 2 B 3.7-18 Revision 0, 2-9 Amendment No. 302,

CREV System B 3.7.3 BASES (continued)

LCO Two redundant subsystems of the CREV System are required to be OPERABLE to ensure that at least one is available, if a single active failure, such as from a loss of both ventilation subsystems or from an inoperable CRE boundary, disables the other subsystem. Total system failure could result in exceeding a TEDE of 5 REM to the CRE occupants in the event of a DBA.

Each CREV subsystem is considered OPERABLE when the individual components necessary to limit CRE occupant exposure are OPERABLE in both subsystems. A subsystem is considered OPERABLE when its associated:

a. Fan is OPERABLE;

b. HEPA filter and charcoal adsorbers are not excessively restricting flow and are capable of performing their filtration functions; and

c. The electric duct heater, ductwork, and dampers are OPERABLE.

Charcoal adsorbers are considered OPERABLE when Ventilation Filter Testing Program (VFTP) acceptance criteria are met and the electric duct heater functions to support the charcoal adsorber function. The HEPA filter is considered OPERABLE when VFTP acceptance criteria are met.

In order for the CREV subsystem to be considered OPERABLE, the CRE boundary must be maintained such that the CRE occupant dose from a large radioactive release does not exceed the calculated dose in the licensing basis consequences analyses for DBAs, and that the CRE occupants are protected from hazardous chemicals and smoke.

BFN does not have automatic CREV actuations for hazardous chemicals or smoke. Current practices at BFN do not utilize (continued)

BFN-UNIT 2 B 3.7-19 Revision 0, 2-9 Amendment No. 283, 3G2,

CREV System B 3.7.3 BASES LCO (continued) chemicals of sufficient quantity to present a chemical hazard to the CRE. Smoke is not considered in the current BFN safety analysis. Therefore, BFN has no specific limits on chemical hazards or smoke.

The LCO is modified by a Note allowing the CRE boundary to be opened intermittently under administrative controls. This Note only applies to openings in the CRE boundary that can be rapidly restored to the design condition, such as doors, hatches, floor plugs and access panels. For entry and exit through doors the administrative control of the opening is performed by the person(s) entering or exiting the area. For other openings, these controls should be proceduralized and consist of stationing a dedicated individual at the opening who is in continuous communication with the operators and CRE.

This individual will have a method to rapidly close the opening and to restore the CRE boundary to a condition equivalent to the design condition when a need for CRE isolation is indicated.

(continued)

BFN-UNIT 2 B 3.7-19a Revision 0, 2-9 Amendment No. 283, W02,

CREV System B 3.7.3 BASES (continued)

APPLICABILITY In MODES 1, 2, and 3, the CREV System must be OPERABLE to ensure that the CRE will remain habitable during and following a DBA, since the DBA could lead to a fission product release.

In MODES 4 and 5, the probability and consequences of a DBA are reduced because of the pressure and temperature limitations in these MODES. Therefore, maintaining the CREV System OPERABLE is not required in MODE 4 or 5, except for during operations with potential for draining the reactor vessel (OPDRVs).

ACTIONS A._1 With one CREV subsystem inoperable, for reasons other than an inoperable CRE boundary, or inoperable HEPA filter or inoperable charcoal adsorbers (which do not impact the ability of the CREV subsystems to meet flowrate requirements specified in the VFTP), the inoperable CREV subsystem must be restored to OPERABLE status within 7 days. With the unit in this condition, the remaining OPERABLE CREV subsystem is adequate to perform the CRE occupant protection function.

However, the overall reliability is reduced because a failure in the OPERABLE subsystem could result in loss of the CREV System function. The 7 day Completion Time is based on the low probability of a DBA occurring during this time period, and that the remaining subsystem can provide the required capabilities.

(continued)

BFN-UNIT 2 B 3.7-20 Revision 9, 2-9 Amendment

CREV System B 3.7.3 BASES ACTIONS B.1, B.2, and B.3 (continued)

If the unfiltered inleakage of potentially contaminated air past the CRE boundary and into the CRE can result in a CRE occupant radiological dose greater than the calculated dose of the licensing basis analyses of DBA consequences (allowed to be up to 5 REM TEDE) the CRE boundary is inoperable.

As discussed in the Applicable Safety Analysis Section, the BFN licensing bases notes that CRE inleakage limits for hazardous chemicals and smoke are not needed to protect the CRE occupants. Since the limit established for radiological events is limiting, verification of smoke and chemical hazards by administrative means is acceptable for an inoperable CRE boundary. Verification that the periodic check of onsite and offsite hazardous chemical sources has been performed within the time limit defined by the Control Room Habitability Program is an acceptable means to ensure the CRE occupants are protected from chemical hazards and smoke.

Actions must be taken to restore an OPERABLE CRE boundary within 90 days.

During the period that the CRE boundary is considered inoperable, action must be initiated to implement mitigating actions to lessen the effect on CRE occupants from the potential hazards of a radiological or chemical event or a challenge from smoke. Actions must be taken within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to verify that in the event of a DBA, the mitigating actions will ensure that CRE occupant radiological exposures will not exceed the calculated dose of the licensing basis analyses of DBA consequences and that CRE occupants are protected from hazardous chemicals and smoke. These mitigating actions (i.e., actions that are taken to offset the consequences of the inoperable CRE boundary) should be preplanned for implementation upon entry into the condition, (continued)

BFN-UNIT 2 B 3.7-21 Revision G, 2-Amendment No. 2-8,, 302 October 16, 2009

CREV System B 3.7.3 BASES ACTIONS B.1, B.2, and B.3 (continued) regardless of whether entry is intentional or unintentional. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Time is reasonable based on the low probability of a DBA occurring during this time period and the use of mitigating actions. The 90 day Completion Time is reasonable based on the determination that the mitigating actions will ensure protection of CRE occupants within analyzed limits while limiting the probability that CRE occupants will have to implement protective measures that may adversely affect their ability to control the reactor and maintain it in a safe shutdown condition in the event of a DBA. In addition, the 90 day Completion Time is a reasonable time to diagnose, plan and possibly repair, and test most problems within the CRE boundary.

C.1 With two CREV subsystems inoperable due to a HEPA filter inoperable or both CREV subsystems' charcoal adsorbers inoperable, which do not impact the ability of the CREV subsystems to meet flowrate requirements specified in the VFTP, the HEPA filter and one of the charcoal adsorbers must be restored within 7 days. The 7 day Completion Time is based on the analysis for radiological dose to CRE occupants (Ref. 10),

which has determined that the CRE 30 day dose after a DBA does not exceed 5 rem (TEDE) without credit for either the HEPA filter or the charcoal adsorbers.

D.1 With one CREV subsystem inoperable due to one inoperable charcoal adsorber, which does not impact the ability of the associated CREV subsystem to meet flowrate requirements specified in the VFTP, the charcoal adsorber must be restored within 14 days. The 14 day Completion Time is based on the analysis for radiological dose to CRE occupants (Ref 10),

which has determined that the CRE 30 day dose after (continued)

BFN-UNIT 2 B 3.7-21a Revision 0, 2-9 Amendment No. 2-8,, W22,

CREV System B 3.7.3 BASES ACTIONS a DBA does not exceed 5 rem (TEDE) without credit for either (continued) the HEPA filter or the charcoal adsorbers, and the capability of the remaining OPERABLE CREV subsystem.

E.1 and E.2 In MODE 1, 2, or 3, if the inoperable CREV subsystem(s) or the CRE boundary cannot be restored to OPERABLE status within the required Completion Time, the unit must be placed in a MODE that minimizes accident risk. To achieve this status, the unit must be placed in at least MODE 3 within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and in MODE 4 within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The allowed Completion Times are reasonable, based on operating experience, to reach the required unit conditions from full power conditions in an orderly manner and without challenging unit systems.

F.1 and F.2 During OPDRVs, if the inoperable CREV subsystem cannot be restored to OPERABLE status within the required Completion Time, the OPERABLE CREV subsystem may be placed in the pressurization mode. This action ensures that the remaining subsystem is OPERABLE, that no failures that would prevent automatic actuation will occur, and that any active failure will be readily detected.

An alternative to Required Action F.1 is to immediately initiate actions to suspend OPDRVs to minimize the probability of a vessel draindown and the subsequent potential for fission product release. Actions must continue until the OPDRVs are suspended.

(continued)

BFN-UNIT 2 B 3.7-22 Revision 0, 2-9 Amendment No. 283, 302,

CREV System B 3.7.3 BASES ACTIONS (continued)

G.1 If both CREV subsystems are inoperable in MODE 1, 2, or 3 for reasons other than Condition B or Condition C, the CREV System may not be capable of performing the intended function and the unit is in a condition outside the accident analyses.

Therefore, LCO 3.0.3 must be entered immediately.

H.1 During OPDRVs, a) with two CREV subsystems inoperable for reasons other than an inoperable HEPA filter or inoperable charcoal adsorbers, b) with one or more CREV subsystems inoperable due to an inoperable CRE boundary, or c) if the HEPA filter and charcoal adsorbers can not be restored to OPERABLE status within the required Completion Time, actions must be initiated immediately to suspend OPDVRs to minimize the probability of a vessel draindown and subsequent potential for fission product release. Actions must continue until the OPDRVs are suspended.

(continued)

BFN-UNIT 2 B 3.7-23 Revision Q, 2-9 Amendment No. 28, W2,

CREV System B 3.7.3 BASES (continued)

SURVEILLANCE REQUIREMENTS SR 3.7.3.1 This SR verifies that a subsystem in a standby mode starts on demand and continues to operate. Standby systems should be checked periodically to ensure that they start and function properly. As the environmental and normal operating conditions of this system are not severe, testing each subsystem once every month provides an adequate check on this system.

Monthly heater operation dries out any moisture that has accumulated in the charcoal as a result of humidity in the ambient air. The CREV System must be operated for > 10 continuous hours with the heaters energized to dry out any moisture and to demonstrate the function of the system.

Furthermore, the 31 day Frequency is based on the known reliability of the equipment and the two subsystem redundancy available.

SR 3.7.3.2 This SR verifies that the required CREV testing is performed in accordance with the VFTP. The VFTP includes testing HEPA filter performance, charcoal adsorber efficiency, minimum system flow rate, and the physical properties of the activated charcoal (general use and following specific operations).

Specific test frequencies and additional information are discussed in detail in the VFTP.

(continued)

BFN-UNIT 2 B 3.7-24 Revision 0 Amendment

CREV System B 3.7.3 BASES SURVEILLANCE REQUIREMENTS (continued)

SR 3.7.3.3 This SR verifies that on an actual or simulated initiation signal, each CREV subsystem starts and operates. This SR includes verification that dampers necessary for proper CREV operation function as required. The LOGIC SYSTEM FUNCTIONAL TEST in SR 3.3.7.1.4 and SR 3.3.7.1.6 overlaps this SR to provide complete testing of the safety function. The frequency of 24 months is based on BFN's normal operating time.

SR 3.7.3.4 This SR verifies the OPERABILITY of the CRE boundary by testing for unfiltered air inleakage past the CRE boundary and into the CRE. The details of the testing are specified in the Control Room Envelope Habitability Program.

The CRE is considered habitable when the radiological dose to CRE occupants calculated in the licensing basis analyses of DBA consequences is no more that 5 REM TEDE and the CRE occupants are protected from hazardous chemicals and smoke.

There is no automatic CREV actuation for hazardous chemical releases or smoke and there are no Surveillance Requirements to verify the OPERABILITY in cases of hazardous chemicals or smoke. This SR verifies that the unfiltered air inleakage into the CRE is no greater than the flow rate assumed in the licensing basis analysis of DBA consequences. When unfiltered air inleakage is greater than the assumed flow rate, Condition B must be entered. Required Action B.3 allows time to restore the CRE boundary to OPERABLE status provided mitigating actions can ensure that the CRE remains within the licensing basis habitability limits for occupants following an accident.

Compensatory measures are discussed in Regulatory Guide 1.196, Section C.2.7.3, (Ref. 6) which endorses, with exceptions, NEI 99-03, Section 8.4 and Appendix F (Ref. 7).

These compensatory measures may also be used as mitigating actions as required by Required Action B.2. Temporary analytical methods may also be used as compensatory (continued)

BFN-UNIT 2 B 3.7-25 Amendment No. 255, 302 October 16, 2009

CREV System B 3.7.3 BASES SURVEILLANCE SR 3.7.3.4 (continued)

REQUIREMENTS measures to restore OPERABILITY (Ref. 8). Options for restoring the CRE boundary to OPERABLE status include changing the licensing basis DBA consequences analysis, repairing the CRE boundary, or a combination of these actions.

Depending upon the nature of the problem and the corrective action, a full scope inleakage test may not be necessary to establish that the CRE boundary has been restored to OPERABLE status.

REFERENCES

1.

FSAR, Section 10.12.

2.

FSAR, Chapter 10.

3.

FSAR, Chapter 14.

4.

FSAR, Section 14.6.

5.

NRC No.93-102, "Final Policy Statement on Technical Specification Improvements," July 23, 1993.

6.

NRC Regulatory Guide 1.196, "Control Room Habitability At Light-Water Power Reactors," January, 2007.

7.

NEI 99-03, "Control Room Habitability Assessment," June, 2001.

8.

Letter from Eric J. Leeds (NRC) to James W. Davis (NEI) dated January 30, 2004, "NEI Draft White Paper, Use of Generic Letter 91-18 Process and Alternative Source Terms in the Context of Control Room Habitability,"

(ADAMS Accession No. ML040300694).

9.

FSAR, Chapter 10.12.5.3, Toxic Gas Protection.

10. TVA Design Output Calculation NDQ0031920075, "Control Room and Offsite Doses Due to a LOCA," Revision 21.

BFN-UNIT 2 B 3.7-25a Amendment No. 2-5%, 3-2,

CREV System B 3.7.3 B 3.7 PLANT SYSTEMS B 3.7.3 Control Room Emergency Ventilation (CREV) System BASES BACKGROUND The CREV System provides a protected environment from occupants can control the unit following an uncontrolled release of radioactivity.

The safety related function of the CREV System includes two independent and redundant high efficiency air filtration subsystems for emergency treatment of outside supply air and a Control Room Envelope (CRE) boundary that limits the inleakage of unfiltered air. The CREV System has a high efficiency particulate air (HEPA) filter bank in the portion of the inletpiping common to both subsystems. Each CREV subsystem consists of a motor-driven fan, an electric duct air heater, an activated charcoal adsorber section, an electric charcoal heater, and the associated ductwork, valves or dampers, doors, barriers, and instrumentation. The HEPA filter bank removes particulate matter, which may be radioactive.

The charcoal adsorbers provide a holdup period for gaseous iodine, allowing time for decay.

The CRE is the area within the confines of the CRE boundary that contains the spaces that control room occupants inhabit to control the unit during normal and accident conditions. This area encompasses the control room, and may encompass other non-critical areas to which frequent personnel access or continuous occupancy is not necessary in the event of an accident. The CRE is protected during normal operation, natural event and accident conditions. The CRE boundary is the combination of walls, floors, roof, ducting, doors, penetrations and equipment that physically form the CRE. The OPERABILITY of the CRE boundary must be maintained to ensure that the inleakage of unfiltered air into the CRE will not (continued)

BFN-UNIT 3 B 3.7-17 Revision 0, 2-9 Amendment No. 2-64-,

CREV System B 3.7.3 BASES BACKGROUND (continued) exceed the inleakage assumed in the licensing basis analysis of design basis accident (DBA) consequences to CRE occupants. The CRE and its boundary are defined in the Control Room Envelope Habitability Program.

Upon receipt of the initiation signal(s) (indicative of conditions that could result in radiation exposure to CRE occupants), the CREV System automatically switches to the pressurization mode of operation to minimize infiltration of contaminated air into the CRE. A system of dampers isolates the CRE. Outside air is taken in through the CREV System ventilation intake and is passed through one of the charcoal adsorber filter subsystems for removal of airborne radioactive particles.

The CREV System is designed to maintain a habitable environment in the CRE for a 30 day continuous occupancy after a DBA without exceeding 5 REM total effective dose equivalent (TEDE). A single CREV subsystem operating at a flow rate of 3000 cfm + 10 percent will pressurize the CRE to about 0.125 inches water gauge to minimize infiltration of air from all surrounding areas adjacent to CRE boundary and the outdoors. CREV System operation in maintaining CRE habitability is discussed in the FSAR, Section 10.12 (Ref. 1).

(continued)

BFN-UNIT 3 B 3.7-17a Revision 0, 2-9 Amendment No. 261 October 16, 2009

CREV System B 3.7.3 BASES (continued)

APPLICABLE SAFETY ANALYSIS The ability of the CREV System to maintain the habitability of the CRE is an explicit assumption for the safety analyses presented in the FSAR, Chapters 10 and 14 (Refs. 2 and 3, respectively). The pressurization mode of the CREV System is assumed to operate following a DBA, as discussed in the FSAR, Section 14.6 (Ref. 4). The analyses for radiological doses to CRE occupants as a result of the various DBAs are summarized in References 3 and 10. No credit is taken in the analyses for filtration by the HEPA filter or charcoal adsorbers. No single active failure will cause the loss of pressurization capability using outside air from the CRE.

There are no offsite or onsite hazardous chemicals that would pose a credible threat to CRE habitability (Ref 9). Consequently, engineering controls for the CRE are not required to ensure habitability against chemical threat.

The evaluation of a smoke challenge demonstrated that smoke will not result in the inability of the CRE occupants to control the reactor either from the control room or remote shutdown system (Ref 9).

The assessment verified that a fire or smoke event anywhere within the plant should not simultaneously render the remote shutdown system and the CRE uninhabitable, nor would it prevent access from the CRE to the remote shutdown system in the event remote shutdown is required. No automatic CREV actuation is required for hazardous chemical releases or smoke and no Surveillance Requirements are required to verify OPERABILITY in cases of hazardous chemicals or smoke.

The CREV System satisfies Criterion 3 of the NRC Policy Statement (Ref. 6).

(continued)

BFN-UNIT 3 B 3.7-18 Revision Q, 2-9 Amendment No. 264-,

CREV System B 3.7.3 BASES (continued)

LCO Two redundant subsystems of the CREV System are required to be OPERABLE to ensure that at least one is available, if a single active failure, such as from a loss of both ventilation subsystems or from an inoperable CRE boundary, disables the other subsystem. Total system failure could result in exceeding a TEDE of 5 REM to the CRE occupants in the event of a DBA.

Each CREV subsystem is considered OPERABLE when the individual components necessary to limit CRE occupant exposure are OPERABLE. A subsystem is considered OPERABLE when its associated:

a. Fan is OPERABLE;

b. HEPA filter and charcoal adsorbers are not excessively restricting flow and are capable of performing their filtration functions; and

c. The electric duct heater, ductwork, and dampers are OPERABLE.

Charcoal adsorbers are considered OPERABLE when Ventilation Filter Testing Program (VFTP) acceptance criteria are met and the electric duct heater functions. The HEPA filter is considered OPERABLE when VFTP acceptance criteria are met.

In order for the CREV subsystems to be considered OPERABLE, the CRE boundary must be maintained such that the CRE occupant dose from a large radioactive release does not exceed the calculated dose in the licensing basis consequences analyses for DBAs, and that the CRE occupants are protected from hazardous chemicals and smoke.

BFN does not have automatic CREV actuations for hazardous chemicals or smoke. Current practices at BFN do not utilize.

(continued)

BFN-UNIT 3 B 3.7-19 Revision 0, 29 Amendment No. 241-, 26-1-,

CREV System B 3.7.3 BASES LCO (continued) chemicals or sufficient quantity to present a chemical hazard to the CRE. Smoke is not considered in the current BFN safety analysis. Therefore, BFN has no specific limits on chemical hazards or smoke.

The LCO is modified by a Note allowing the CRE boundary to be opened intermittently under administrative controls. This Note only applies to openings in the CRE boundary that can be rapidly restored to the design condition such as doors, hatches, floor plugs, and access panels. For entry and exit through doors the administrative control of the opening is performed by the person(s) entering or exiting the area. For other openings, these controls should be proceduralized and consist of stationing a dedicated individual at the opening who is in continuous communication with the operators in the CRE. This individual will have a method to rapidly close the opening and to restore the CRE boundary to a condition equivalent to the design condition when a need for CRE isolation is indicated.

(continued)

BFN-UNIT 3 B 3.7-19a Revision 0, 2-9 Amendment No. 244, 26-1-,

CREV System B 3.7.3 BASES (continued)

APPLICABILITY In MODES 1, 2, and 3, the CREV System must be OPERABLE to ensure that the CRE will remain habitable during and following a DBA, since the DBA could lead to a fission product release.

In MODES 4 and 5, the probability and consequences of a DBA are reduced because of the pressure and temperature limitations in these MODES. Therefore, maintaining the CREV System OPERABLE is not required in MODE 4 or 5, except for during operations with potential for draining the reactor vessel (OPDRVs).

ACTIONS A.1 With one CREV subsystem inoperable, for reasons other than an inoperable CRE boundary, or inoperable HEPA filter or inoperable charcoal adsorbers (which do not impact the ability of the CREV subsystems to meet flowrate requirements specified in the VFTP), the inoperable CREV subsystem must be restored to OPERABLE status within 7 days. With the unit in this condition, the remaining OPERABLE CREV subsystem is adequate to perform the CRE occupant protection function.

However, the overall reliability is reduced because a failure in the OPERABLE subsystem could result in a loss of the CREV System function. The 7 day Completion Time is based on the low probability of a DBA occurring during this time period, and that the remaining subsystem can provide the required capabilities.

(continued)

BFN-UNIT 3 B 3.7-20 Revision 0, 2-9 Amendment

CREV System B 3.7.3 BASES ACTIONS B.1, B.2 and B.3 (continued)

If the unfiltered inleakage of potentially contaminated air past the CRE boundary and into the CRE can result in a CRE occupant radiological dose greater than the calculated dose of the licensing basis analyses of DBA consequences (allowed to be up to 5 REM TEDE) the CRE boundary is inoperable.

As discussed in the Applicable Safety Analysis Section, the BFN licensing bases notes that CRE inleakage limits for hazardous chemicals and smoke are not needed to protect the CRE occupants. Since the limit established for radiological events is limiting, verification of smoke and chemical hazards by administrative means is acceptable for an inoperable CRE boundary. Verification that the periodic check of onsite and offsite hazardous chemical sources has been performed within the time limit defined by the Control Room Habitability Program is an acceptable means to ensure the CRE occupants are protected from chemical hazards and smoke.

Actions must be taken to restore an OPERABLE CRE boundary within 90 days.

During the period that the CRE boundary is considered inoperable, action must be initiated to implement mitigating actions to lessen the effect on CRE occupants from the potential hazards of a radiological or chemical event or a challenge from smoke. Actions must be taken within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to verify that in the event of a DBA, the mitigating actions will ensure that CRE occupant radiological exposures will not exceed the calculated dose of the licensing basis analyses of DBA consequences and that CRE occupants are protected from hazardous chemicals and smoke. These mitigating actions (i.e., actions that are taken to offset the consequences of the inoperable CRE boundary) should be preplanned for implementation upon entry into the condition, regardless of whether entry is intentional or unintentional. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months (continued)

BFN-UNIT 3 B 3.7-21 Revision 0, 2-Amendment No. 244-, 261 October 16, 2009

CREV System B 3.7.3 BASES ACTIONS B.1, B.2 and B.3 (continued)

Completion Time is reasonable based on the low probability of a DBA occurring during this time period and the use of mitigating actions. The 90 day Completion Time is reasonable based on the determination that the mitigating actions will ensure protection of CRE occupants within analyzed limits while limiting the probability that CRE occupants will have to implement protective measures that may adversely affect their ability to control the reactor and maintain it in a safe shutdown condition in the event of a DBA. In addition, the 90 day Completion Time is a reasonable time to diagnose, plan and possibly repair, and test most problems within the CRE boundary.

C.1 With two CREV subsystems inoperable due to a HEPA filter inoperable or both CREV subsystems' charcoal adsorbers inoperable, which do not impact the ability of the CREV subsystems to meet flowrate requirements specified in the VFTP, the HEPA filter and one of the charcoal adsorbers must be restored within 7 days. The 7 day Completion Time is based on the analysis for radiological dose to CRE occupants (Ref.

10), which has determined that the CRE 30 day dose after a DBA does not exceed 5 rem (TEDE) without credit for either the HEPA filter or the charcoal adsorbers.

D.1 With one CREV subsystem inoperable due to one inoperable charcoal adsorber, which does not impact the ability of the associated CREV subsystem to meet flowrate requirements specified in the VFTP, the charcoal adsorber must be restored within 14 days. The 14 day Completion Time is bases on the analysis for radiological dose to CRE occupants (Ref. 10), which has determined that the CRE 30 day dose after a DBA does not exceed 5 rem (TEDE) without credit for either (continued)

BFN-UNIT 3 B 3.7-21a Revision 0, 2-9 Amendment No. 244-, 26-1-,

CREV System B 3.7.3 BASES ACTIONS the HEPA filter or the charcoal adsorbers, and the capability of (continued) the remaining OPERABLE CREV subsystem.

E.1 and E.2 In MODE 1, 2, or 3, if the inoperable CREV subsystem(s) or the CRE cannot be restored to OPERABLE status within the required Completion Time, the unit must be placed in a MODE that minimizes accident risk. To achieve this status, the unit must be placed in at least MODE 3 within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and in MODE 4 within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The allowed Completion Times are reasonable, based on operating experience, to reach the required unit conditions from full power conditions in an orderly manner and without challenging unit systems.

F.1 and F.2 During OPDRVs, if the inoperable CREV subsystem cannot be restored to OPERABLE status within the required Completion Time, the OPERABLE CREV subsystem may be placed in the pressurization mode. This action ensures that the remaining subsystem is OPERABLE, that no failures that would prevent automatic actuation will occur, and that any active failure will be readily detected.

An alternative to Required Action F.1 is to immediately initiate actions to suspend OPDRVs to minimize the probability of a vessel draindown and the subsequent potential for fission product release. Actions must continue until the OPDRVs are suspended.

(continued)

BFN-UNIT 3 B 3.7-22 Revision 0, 2-9 Amendment No. 24-1-, 26-1-,

CREV System B 3.7.3 BASES ACTIONS (continued)

G.1 If both CREV subsystems are inoperable in MODE 1, 2, or 3 for reasons other than Condition B or Condition C, the CREV System may not be capable of performing the intended function and the unit is in a condition outside the accident analyses.

Therefore, LCO 3.0.3 must be entered immediately.

H.1 During OPDRVs, a) with two CREV subsystems inoperable for reasons other than an inoperable HEPA filter or inoperable charcoal adsorbers, b) with one or more CREV subsystems inoperable due to an inoperable CRE boundary, or c) if the HEPA filter and charcoal adsorbers can not be restored within the required Completion Time, actions must be initiated immediately to suspend OPDVRs to minimize the probability of a vessel draindown and subsequent potential for fission product release. Actions must continue until the OPDRVs are suspended.

(continued)

BFN-UNIT 3 B 3.7-23 Revision 0, 2-9 Amendment No. 241-, 261-,

CREV System B 3.7.3 BASES (continued)

SURVEILLANCE REQUIREMENTS SR 3.7.3.1 This SR verifies that a subsystem in a standby mode starts on demand and continues to operate. Standby systems should be checked periodically to ensure that they start and function properly. As the environmental and normal operating conditions of this system are not severe, testing each subsystem once every month provides an adequate check on this system.

Monthly heater operation dries out any moisture that has accumulated in the charcoal as a result of humidity in the ambient air. The CREV System must be operated for 2! 10 continuous hours with the heaters energized to dry out any moisture and to demonstrate the function of the system.

Furthermore, the 31 day Frequency is based on the known reliability of the equipment and the two subsystem redundancy available.

SR 3.7.3.2 This SR verifies that the required CREV testing is performed in accordance with the VFTP. The VFTP includes testing HEPA filter performance, charcoal adsorber efficiency, minimum system flow rate, and the physical properties of the activated charcoal (general use and following specific operations).

Specific test frequencies and additional information are discussed in detail in the VFTP.

(continued)

BFN-UNIT 3 B 3.7-24 Revision 0 Amendment

CREV System B 3.7.3 BASES SURVEILLANCE REQUIREMENTS (continued)

SR 3.7.3.3 This SR verifies that on an actual or simulated initiation signal, each CREV subsystem starts and operates. This SR includes verification that dampers necessary for proper CREV operation function as required. The LOGIC SYSTEM FUNCTIONAL TEST in SR 3.3.7.1.4 and SR 3.3.7.1.6 overlaps this SR to provide complete testing of the safety function. The frequency of 24 months is based on BFN's normal operating cycle.

SR 3.7.3.4 This SR verifies the OPERABILITY of the CRE boundary by testing for unfiltered air inleakage past the CRE boundary and into the CRE. The details of the testing are specified in the Control Room Envelope Habitability Program.

The CRE is considered habitable when the radiological dose to CRE occupants calculated in the licensing basis analyses of DBA consequences is no more that 5 REM TEDE and the CRE occupants are protected from hazardous chemicals and smoke.

There is no automatic CREV actuation for hazardous chemical releases or smoke and there are no Surveillance Requirements to verify the OPERABILITY in cases of hazardous chemicals or smoke. This SR verifies that the unfiltered air inleakage into the CRE is no greater than the flow rate assumed in the licensing basis analysis of DBA consequences. When unfiltered air inleakage is greater than the assumed flow rate, Condition B must be entered. Required Action B.3 allows time to restore the CRE boundary to OPERABLE status provided mitigating actions can ensure that the CRE remains within the licensing basis habitability limits for occupants following an accident.

Compensatory measures are discussed in Regulatory Guide 1.196, Section C.2.7.3, (Ref. 6) which endorses, with exceptions, NEI 99-03, Section 8.4 and Appendix F (Ref. 7).

These compensatory measures may also be used as mitigating actions as required by Required Action B.2. Temporary analytical methods may also be used as compensatory (continued)

BFN-UNIT 3 B 3.7-25 Amendment No. 2-1-5, 261 October 16, 2009

CREV System B 3.7.3 BASES SURVEILLANCE SR 3.7.3.4 (continued)

REQUIREMENTS measures to restore OPERABILITY (Ref. 8). Options for restoring the CRE boundary to OPERABLE status include changing the licensing basis DBA consequences analysis, repairing the CRE boundary, or a combination of these actions.

Depending upon the nature of the problem and the corrective action, a full scope inleakage test may not be necessary to establish that the CRE boundary has been restored to OPERABLE status.

REFERENCES

1.

FSAR, Section 10.12.

2.

FSAR, Chapter 10.

3.

FSAR, Chapter 14.

4.

FSAR, Section 14.6.

5.

NRC No.93-102, "Final Policy Statement on Technical Specification Improvements," July 23, 1993.

6.

NRC Regulatory Guide 1.196, "Control Room Habitability At Light-Water Power Reactors," January 2007.

7.

NEI 99-03, "Control Room Habitability Assessment," June 2001.

8.

Letter from Eric J. Leeds (NRC) to James W. David (NEI) dated January 30, 2004, "NEI Draft White Paper, Use of Generic Letter 91-18 Process and Alternative Source Terms in the Context of Control Room Habitability,"

(ADAMS Accession No. ML040300694).

9.

FSAR, Chapter 10.12.5.3, Toxic Gas Protection.

10. TVA Design Output Calculation NDQ0031920075, "Control Room and Offsite Doses Due to LOCA," Revision 21.

BFN-UNIT 3 B 3.7-25a Amendment No. 2-4-5, 2-64-,

v t e Letter Sequence Request
TAC:ME4668, (Approved, Closed)
Initiation Request, Request Acceptance Supplement Administration Questions 10 March 2011 Answers Results Approval, Approval Other:
MONTHYEAR2011-12-21 [Table View]

ML12017A161

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Subject:

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