ML18036A296
| ML18036A296 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 07/12/1991 |
| From: | TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML18036A295 | List: |
| References | |
| NUDOCS 9107180115 | |
| Download: ML18036A296 (17) | |
Text
ENCLOSURE 1 PROPOSED TECHNICAL SPECIFICATION REVISIONS BROMNS FERRY NUCI EAR PLANT (BFN)
(TVA BFN TECHNICAL SPECIFICATION AMENDMENTS 295 AND 298T) 9107180115 910712 PDR ADOCK 05000259 P
PDR 't nfl
N.
Rated Power Rated power refers to operation at a reactor power of 3,293 1%it; this is also termed 100 percent power and is the maximum power level authorized by the operating license.
Rated steam flow, rated coolant flow, rated neutron flux, and rated nuclear system pressure refex to the values of these parameters when the reactor is at rated power.
Design power, the power to which the safety analysis applies, corresponds to 3,440 MWt.
0.
Prima Conta nme t Xnte rit Primary containment integrity means that the drywell and pressure suppression chamber are intact and all of the following conditions are satisfied:
- l. All nonautomatic containment isolation valves on lines connected to the reactor coolant systems or containment which are not required to be open during accident conditions are closed.
These valves may be opened to perform necessary operational activities.
2.
At least one door in each airlock is closed and sealed.
3.
All automatic containment isolation valves are operable or each line which contains an inoperable isolation valve is isolated as required by specification 3.7.D.2.
4.
All blind flanges and manways are closed.
P.
Seconda Containment Inte rit 1.
Secondary containment. integrity means that the required unit reactor zones and refueling zone are intact and the following conditions are met:
a)
At least one door in each access opening to the turbine building, control bay and out-of-doors is closed.
b)
The standby gas treatment system is operable and can maintain 0.25 inches of water negative pressure in those areas where secondary containment integrity is stated to exist c)
All secondary containment penetrations required to be closed during accident conditions are either:
1.
Capable of being closed by an operable secondary co'ntainment automatic isolation system, or 2.
Closed by at least one secondary containment automatic isolation valve deactivated in the isolated position.
2.
Reactor zone secondary containment integrity means the unit reactor building is intact and the following conditions are met:
a)
At least one door between any opening to the turbine building, control bay and out-of-doors is closed.
BFH Unit 1
N.
Rated Power Rated power refers to operation at a reactor power of 3,293 MWt; this is also termed 100 percent power and is the maximum power level authorized by the operating license.
Rated steam flow, rated coolant flow, rated neutron flux, and rated nuclear system pressure refer to the values of these parameters when the reactor is at rated power.
Design power, the power to which the safety analysis applies, corresponds to 3,440 MWt.
0.
Prima Conta nment nte r t Primary containment integrity means that the drywell and pressure suppression chamber are intact and all of the following conditions are satisfied:
1.
All nonautomatic containment isolation valves on lines connected to the reactor coolant systems or containment which are not required to be open during accident conditions are closed.
These valves may be opened to perform necessary operational activities.
2.
At least one door in each airlock is closed and sealed.
3.
All automatic containment isolation valves are operable or each line which contains an inoperable isolation valve is isolated as required by specification 3.7.D.2.
4.
All blind flanges and manways are closed.
P.
Seconda Containment Inte rit 1.
Secondary containment integrity means that the required unit reactor zones and refueling zone are intact and the following conditions are met:
a)
At least one door in each access opening to the turbine building, control bay and out-of-doors is closed.
b)
The standby gas treatment system is operable and can maintain 0.25 inches of water negative pressure in those areas where secondary containment integrity is stated to exist.
c)
All secondary containment penetrations required to be closed during accident conditions are either:
1.
Capable of being closed by an operable secondary containment automatic isolation system, or 2.
Closed by at least one secondary containment automatic isolation valve deactivated in the isolated position.
2.
Reactor zone secondary containment integrity means the unit reactor building is intact and the following conditions are met:
a)
At least one door between any opening to the turbine building, control bay and out-of-doors is closed.
BFH Unit 2 1.0-5
N.
Rated Power Rated power refers to operation at a reactor power of 3,293 MHt; this is also termed 100 percent power and is the maximum power level authorized by the operating license.
Rated steam flow, rated coolant flow, rated neutron flux, and rated nuclear system pressure refer to the values of these parameters when the reactor is at rated power.
Design power, the power to which the safety analysis applies, corresponds to 3,440 MWt.
0.
Prima Containment Inte rit Primary containment integrity means that the drywell and pressure suppression chamber are intact and all of the following conditions are satisfied:
1.
All nonautomatic containment isolation valves on lines connected to the reactor coolant system or containment which are not required to be open during accident "conditions are closed.
These valves may be opened to perform necessary operational activities.
2.
At least one door in each airlock is closed and sealed.
3.
All automatic containment isolation valves are operable or each line which contains an inoperable isolation valve is isolated as required by specification 3.7.D.2.
4.
All blind flanges and manways are closed.
P.
Seconda Containment Inte rit 1.
Secondary containment integrity means that the required unit reactor zones and refueling zone are intact and the following conditions are met:
a)
At least one door in each access opening to the turbine building, control bay and out-of-doors is closed.
b)
The standby gas treatment system is operable and can maintain 0.25 inches of water negative pressure in those areas where secondary containment integrity is stated to exist.
c)
All secondary containment penetrations required to be closed during accident conditions are either:
1.
Capable of being closed by an operable secondary containment automatic isolation position, or 2.
Closed by at least one secondary containment automatic isolation valve deactivated in the isolated position.
2.
Reactor zone secondary containment integrity means the unit reactor building is intact and the following conditions are met:
a)
At least one door between any opening to the turbine building, control bay and out-of-doors is closed.
BFN Unit 3 1.0-5
3,7 4.7 CONTAINMENT SYSTEMS LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS 3.7.B. Standb Gas T eatment S stem 4.7.B.
Standb Gas eatment
~Sstem 3.7.B.4 (Cont'd) b.
Place all reactors in at least a HOT SHUTDOWN CONDITION within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in a COLD SHUTDOWN CONDITION within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
3.7.C.
Seconda Containment 4.7.C.
Seconda Containment
- 1.
Secondary containment integrity shall be maintained in the reactor zone at all times except as specified in 3.7.C.2.
- LCO not applicable until just, prior to loading fuel into the Unit 3 reactor vessel, provided the Unit 3 reactor zone is not required for secondary containment integrity for other units.
Secondary containment surveillance shall be performed as indicated below:
a.
Secondary containment capability to maintain 1/4 inch of water vacuum under calm wind
(<
5 mph) conditions with a system inleakage rate of not more than 12,000 cfm, shall be demonstrated at each refueling outage prior to refueling.
- 2. If reactor zone secondary containment integrity cannot be maintained the following conditions shall be met:
a.
Suspend all fuel handling operations, core altera-
- tions, and activities with the potential to drain any reactor vessel containing fuel.
b.
Restore reactor zone secondary containment integrity within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, or place all reactors in at least a HOT SHUTDOWN CONDITION within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in a COLD SHUT-DOWN CONDITION within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
2.
After a secondary containment violation is determined, the standby gas treatment system will be operated immediately after the affected zones are isolated from the remainder of the secondary containment to confirm its ability to maintain the remainder of the secondary containment at 1/4-inch of water negative pressure under calm wind conditions.
BFN Unit 3 3.7/4.7-16
ENCLOSURE 2 BROWNS FERRY NUCLEAR PLANT (BFN)
SUMMARY
OF CHANGES Summar of Chan es:
Technical Specification Amendment 295 1.
Revision to Definition 1.0.P.1 (for Units 1, 2 and 3), "Secondary Containment Integrity".
The current definition states:
Secondary containment integrity means that the reactor building is intact and the following conditions are met:
Proposed change to 1.0.P.1 better defines the zonal boundary concept of Secondary Containment by changing the text to read:
Secondary containment integrity means that the required unit reactor zones and refueling zone are intact and the following conditions are met:
2.
Revision to Definition 1.0.P.2 (for Unit 3),
"Secondary Containment Integrity".
Proposed change to 1.0.P.2 corrects typographical errors such that the definitions for secondary containment integrity read the same for all three units.
Temporary Technical Specification Amendment 298T 1.
Revision to Limiting Condition for Operation (LCO) 3.7.C.1 (for Unit 3),
The current LCO 3.7.C.1 states:
Secondary containment integrity shall be maintained in the reactor zone at all times except as specified is 3.7.C.2.
Proposed temporary change to 3.7.C.1 would add an asterisk to section 3.7.C.1 that refers to a note which modifies the applicability of 3.7.C.1 as:
LCO not applicable until just prior to loading fuel into the Unit 3 reactor vessel, provided the Unit 3 reactor zone is not required for secondary containment integrity for other units.
ENCLOSURE 3
BROWNS FERRY NUCLEAR PLANT (BFN)
REASON AND JUSTIFICATION FOR THE PROPOSED CHANGES'eason for Chan es:
TVA is revising Definition 1.0.P.2 (for Unit 3) to correct typographical errors.
These administrative changes will make the definitions for secondary containment integrity read the same for all three units.
Definition 1.0.P.l (for Units 1, 2 and 3) is being revised to better define the zonal boundary concept of Secondary Containment.
The BFN Unit 3 Technical Specifications are temporarily being revised to allow the isolation of the Unit 3 reactor zone from the secondary containment boundary without impacting the continued operation of Unit 2.
Currently, Browns Ferry Unit 2 is in the power ascension test phase, Unit 3 is entering the discovery/walkdown phase of its outage recovery program, and Unit 1 is in long term lay-up.
This change will facilitate the completion of the construction efforts on Unit 3 by allowing the Unit 3 reactor zone to be breached without declaring the secondary containment (recpxired to support ongoing Unit 2 operations) inoperable.
This does not however preclude the return to a four zone (including Unit 3 reactor zone) secondary containment if desired.
Justification for Chan es:
The current wording of Definition 1.0.P.1 (Units 1, 2 and 3) is confusing in that the Secondary Containment is discussed in terms of the reactor building and not in terms of unit reactor zones and the refueling zone.
The proposed change to this section does not reflect a change to the secondary containment
- boundary, but serves to better define the boundary in terms of zones which is consistent with definitions in sections 1.0.P.2 (reactor zone secondary containment) and 1.0.P.3 (refueling zone secondary containment).
These changes are administrative in nature
- and, are therefore justified.
The correction of typographical errors to definition 1.0.P.2 (for Unit 3) does not reflect a physical change to the plant or to the recpxirements for secondary containment integrity.
This change is administrative in nature
- and, is therefore, justified.
The current BFN Technical Specification Limiting Condition for Operation (LCO) 3.7.C.1 states that the secondary containment is needed at all times except as specified in LCO 3.7.C.2.
LCO 3.7.C.2 currently states that the following conditions shall be met if reactor zone secondary containment integrity cannot be maintained:
Suspend all fuel handling operations, core alterations, and activities with the potential to drain
~an reactor vessel containing fuel, and Restore reactor zone secondary containment integrity within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, or place all reactors in at least a hot shutdown condition within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in a cold shutdown condition within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
Page 2 of 6 ENCLOSURE 3 (CONTINUEn)
BROWNS FERRY NUCLEAR PLANT (BFN)
REASON AND JUSTIFICATION FOR THE PROPOSED CHANGES Historically, the requirement to suspend the above activities and shutdown all three units was imposed due to a discrepancy between the BFN Final Safety Analysis Report (FSAR) and the as-found condition in the plant.
As described by TVA letter, dated March 16, 198S, the Browns Ferry FSAR previously stated that all penetrations through the secondary containment envelope were of Seismic Class I design.
The BFN FSAR has been revised to provide a
performance based criteria that requires the secondary containment to be desi.gned such that the Standby Gas Treatment System (SGTS) will be able to maintain the secondary containment at a negative one-quarter inch of water pressure relative to the building exterior following a design basis earthquake (DBE).
Some of the plant features which penetrate secondary containment were identified as not being designed and installed as Seismic Class I commodities.
Since the post>>DBE integrity of the non-seismically qualifi.ed penetration seals could not be ensured, it could be postulated that seal degradation could increase the inleakage flow area.
Sufficient increases in inleakage after a DBE, could render the SGTS incapable of maintaining the required negative 0.25 inch of water vacuum within the secondary containment.
Therefore, radioactive material could potentially bypass the SGTS and be released directly to the environment.
The FSAR requirement cited above is unique for a plant of the Browns Ferry design and vintage (BWR/4 with a Mark 1 Containment).
As stated in the Browns Ferry FSAR, the primary purpose of the secondary containment is to limit the radioactive material released after a design basis accident.
The probability of a design basis accident and a DBE occurring simultaneously is extremely low and therefore, not considered credible.
- However, BFN undertook a very conservative approach and upgraded its penetration seals in order to conform with the FSAR commitment.
BFN's secondary containment penetration program resolved this concern for Unit 2 operations by an evaluation of the penetrations through secondary containment whose boundary was formed by the outer boundary of the reactor building.
This outer boundary was comprised of the walls, floors, roof, etc.,
between the outside environment and all three reactor zones and the refueling floor.
This included the airlocks, refueling floor roof and siding, piping penetrations, heating ventilating and air conditioning (HVAC) duct penetrations, electrical conduit penetrations and cable tray penetrations.
The program did not address inter-zonal penetrations (i.e.,
between th'e refueling floor and the Units.1, 2, or 3 reactor zones or between the Units 1 and 2 reactor zones or between the Unit 2 and Unit 3 reactor zones).
Secondary containment was assured by qualifying the outer boundary of the Reactor Building and no provisions were made for providing secondary containment quali.fication and the isolation of the individual reactor zones.
1>>
,fp
Page 3 of 6 ENCLOSURE 3 (CONTINUED)
BROMNS FERRY NUCLEAR PLANT (BFN)
REASON AND JUSTIFICATION FOR THE PROPOSED CHANGES The existing Secondary Containment System is shown below:
Browns Ferry Reactor Building (Side view)
Refueling Floor Unit 1 Reactor Zone Unit 2 Reactor Zone Unit 3 Reactor Zone Legend:
The evaluated eecondary containment boundary.
The penetrations of these walls, floors, and ceilings have not been evaluated or modified to ensure an analyzed post-design basis earthquake inleakage.
The potential flow paths for the outer boundaries of the Reactor Building were
- modified, as required, to ensure that the total post-DBE inleakage flow would be within the capability of the SGTS to maintain the required 0.25 inch of water vacuum inside secondary containment.
This program was evaluated by NRC and found acceptable as documented in the staff's April ll, 1988 Safety Evaluation Report.
Notification that the design, testing, and modifications required to resolve the discrepancy between the FSAR requirements and the as-constructed configuration of secondary containment penetrations was provided in TVA's October 6,
1989 lettere The current BFN Technical Specification Limiting Condition for Operation (LCO) 3.7.C.
was proposed by TVA letter, dated March 6, 1990 and approved by NRC letter, dated March 30, 1990.
At the time that the March 6, 1990 technical specification was proposed and approved, it required action be taken'for all units, if secondary containment was lost in any location of any unit, because the penetrations between the individual units or between the units and the refueling floor were not evaluated as part of the secondary containment penetrations program.
Page 4 of 6 ENCLOSURE 3 (Con.INuEn)
BROMNS FERRY NUCLEAR PLANT (BFN)
REASON AND JUSTIFICATION FOR THE PROPOSED CHANGES The Secondary Containment System is discussed in Section 5.3 of the Updated Browns Ferry Final Safety Analysis Report (FSAR).
As discussed in that
- section, the safety objective of the Secondary Containment System is to limit the release of radioactive material to the environs after an accident so that the resulting exposures are kept to a practical minimum and are within the guideline values gi.ven in the applicable parts of 10 CFR 20 and 10 CFR 100.
The FSAR further states that the safety design basis of the Secondary Containment System includes:
~
Providing a secondary containment when the primary containments are intact.
In the event of release of radioactive material to the Reactor Building atmosphere, the Secondary Containment System contains the necessary
- reliable, redundant components and subsystems to isolate,
- contain, and assure a controlled filtered elevated release of the Secondary Containment Building atmosphere.
The Secondary Containment System provides primary containment when any of the three Primary Containment Systems are open such as during refueling and maintenance operations.
During normal operation and when isolated, the secondary containment is maintained at a negative pressure relative to the building exterior.
When isolated, the secondary containment atmosphere is filtered by the Standby Gas Treatment System (SGTS) and released from the plant stack.
~
The secondary containment inleakage rate is less than the SGTS capacity when the building is subjected to an internal negative pressure of 0.25 inches of water.
Wind conditions are considered.
~
The Reactor Building is a Seismic Class I structure.
The Secondary Containment System is designed as a Seismic Class I system except for the penetrations through the secondary containment membrane.
These penetrations are designed to limit the inleakage flow in order to maintain a negative pressure inside secondary containment following a DBE.
The other safety design basis of the Secondary Containment System are not germane to this proposed amendment.
Technical Specification definition 1.0.P currently contains the following statements:
1.
Secondary containment integrity means that the reactor building is intact and...
2.
Reactor zone secondary containment integrity means that the unit reactor building is intact and..
~
If it is desirable for operational considerations, a reactor zone may be isolated from the other reactor zones and the refuel zone by maintaining at least one door closed in each common passageway between zones.
Reactor zone safety-related features are not compromised by openings between adjacent units or refuel zone, unless it is desired to isolate a
given zone.
Page 5 of' ENCLOSURE 3 (Cowvxoueo)
BROMNS FERRY NUCLEAR PLANT (BFN)
REASON AND JUSTIFICATION FOR THE PROPOSED CHANGES Based on these statements, it is already recognized that:
- 1) secondary containment integrity can be satisfied by having multiple zones forming a qualified secondary containment boundary entirely around the unit(s) requiring secondary containment, and 2) a zone may be isolated from the other zones if certain provisions are met.
As demonstrated in Chapter 14 of the BFN FSAR, the containment and filtering provided by secondary containment and SGTS allow BFN to maintain its:offsite and control room operator doses below the limits set forth in 10 CFR 100 and 10 CFR 20 for all events which release radioactive material to the secondary containment.
Since the concept of a qualified secondary containment boundary will be maintained and the flow rates associated with secondary containment and SGTS will be maintained, the analyses presented in Chapter 14 of the FSAR remains valid.
The potential flow paths between the Unit 3 reactor zone and the refueling floor and between the Unit 3 and the Unit 2 reactor zones will be designed and
- modified, as required, to ensure that the total post-DBE inleakage flow into the secondary containment boundary required for Unit 2 operation would be within the capability of the SGTS to maintain the required 0.25 inch of water vacuum.
The secondary containment boundary which is required to support Unit 2 operations includes the Units 1 and 2 reactor zones and the refueling floor above the Unit 3 reactor zone.
The proposed Reactor Building configuration is shown below:
Browns Ferry Reactor Building (Side view)
Refueling Floor Unit 1 Reactor Zone Unit 2 Reactor Zone Unit 3 Reactor Zone r.egend:
The penetrations of these walls, floors, and ceilings will be evaluated and/or modified to ensure an analyzed post-design basis earthquake inleakage.
The penetrations of these walls, floors, and ceilings have been evaluated and/or modified to ensure an analyzed post-design basis earthquake inleakage.
The penetrations of these walls, floors, and ceilings have not been evaluated or modified to ensure an analyzed post-design basis earthquake inleakage.
Page 6 of 6 ENCLOSURE 3 (CONTINUED)
BROWNS FERRY NUCLEAR PLANT (BFN)
REASON AND JUSTIFICATION FOR THE PROPOSED CHANGES These modifications will ensure that the safety objective of the Secondary Containment System will be met for operations within Units 1 and 2.
potential release of radioactive material due to operations in Units 1 and 2
will be kept to a practical minimum and will be within the guideline values given in the applicable parts of 10 CFR 20 and 10 CFR 100.
The analysis and modifications to the potential flow paths between the Unit 3 reactor zone and the refueling floor, and the Unit 3 reactor zone and the Unit 2 reactor zone, will satisfy the applicable safety design bases of the Secondary Containment System which are required to support Units 1 and 2
operations.
This includes:
~
Providing a secondary containment when the Units 1 or 2 primary containments are intact.
In the event of release of radioactive material to the secondary containment atmosphere, the Secondary Containment System contains the necessary reliable, redundant components and subsystems to isolate, to contain, and to assure a controlled filtered elevated release.
~
The Secondary Containment System will provide primary containment when either the Units 1 or 2 Primary Containment Systems are open. such as during refueling and maintenance operations.
~
During normal operation of Units 1 or 2 and when isolated, the secondary containment will be maintained at a negative pressure relative to the outside environment.
When isolated, the Units 1 and 2 secondary containment atmosphere will be filtered by the SGTS and released from the plant stack.
~
The Units 1 and 2 secondary containment inleakage rate will be less t'han the SGTS capacity when the Units 1 and 2 reactor zones and the refueling floor is subjected to an internal negative pressure of 0.25 inches of water.
Wind conditions will be considered.
~
The Reactor Building is a Seismic Class I structure.
This includes the wall between the Unit 2 and Unit 3 reactor zones and between the Unit 3 reactor zone and the refueling floor.
The Secondary Containment System is designed as a Seismic Class I system except for the penetrations through the secondary containment membrane.
These penetrations will be designed and modified, as required, to limit the inleakage flow in order to maintain a negative pressure inside the Units 1 and 2 reactor zones and the refueling floor following a Design Basis Earthquake.
Since these changes do not impact the ability of the Secondary Containment System to meet its safety objective or design bases, this temporary change to the Technical Specifications is justified.
ENCLOSURE 4 BROWNS FERRY NUCLEAR PLANT (BFN)
PROPOSED DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATION Descri tion of Pro osed Technical S ecification Amendment The BFN Unit 3 Technical Specifications are being revised as follows:
Technical Specification Amendment 295 1.
Revision to Definition 1.0.P.1 (for Units 1, 2 and 3),
"Secondary Containment Integrity".
The current definition states:
Secondary containment integrity means that the reactor building is intact and the following conditions are mets Proposed change to 1.0.P.1 better defines the zonal boundary concept of Secondary Containment by changing the text to reads Secondary containment integrity means that the required unit reactor zones and refueling zone are intact and the following conditions are mets 2.
Revision to Definition 1.0.P.2 (for Unit. 3),
"Secondary Containment Integrity".
Proposed change to 1.0.P.2 corrects typographical errors such that the definitions for secondary containment integrity read the same for all three units.
Temporary Technical Specification Amendment 298T 1.
Revision to Limiting Condition for Operation (LCO) 3.7.C.1 (for Unit 3),
The current LCO 3.7.C.1 states:
Secondary containment integrity shall be maintained in the reactor zone at all times except as specified is 3.7.C.2.
Proposed temporary change to 3.7.C.l would add an asterisk to section 3.7.C.1 that refers to a note which modifies the applicability of 3.7.C.1 as:
LCO not applicable until just prior to loading fuel into the Unit 3 reactor vessel, provided the Unit 3 reactor zone is not required for secondary containment integrity for other units.
Basis for Pro osed No Si nificant Hazards Consideration Determination NRC has provided standards for determining whether a significant hazards consideration exists as stated in 10 CFR 50.92(c).
A proposed amendment to an operating license involves no significant hazards consideration if operation of the facility in accordance with the proposed amendment would not; (1) involve a significant increase in the probability or consequences of an accident previously evaluated, (2) create the possibility of a new or different kind of accident from an accident previously evaluated, or (3) involve a significant reduction in a margin of safety.
~'
~
Page 2 of 3 ENCLOSURE 4 (CONTXNUED)
BROWNS FERRY NUCLEAR PLANT (BFN)
PROPOSED DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATION 1 ~
2 ~
This proposed change does not significantly increase the probabi.lity or consequences of an accident previously evaluated.
The proposed temporary and permanent changes do not reflect any significant change to any precursor for the design basis events which are analyzed in Chapter 14 of the Browns Ferry Final Safety Analysis Report.
Therefore, the probabi.lity of an accident previously evaluated is not significantly increased.
The proposed temporary and permanent Technical Specification changes do not change the method of isolation or operation of secondary containment or the method of operating the Standby Gas Treatment System (SGTS).
The SGTS is used to process radioactive effluents which could be released to the secondary containment following an accident.
The allowable SGTS flow and corresponding reactor building in-leakage will be maintained in accordance with the Techni.cal Specification surveillance limit of 12,000 cfm at a negative pressure of 0.25 inch of water.
Additionally, there is no change to the design flow rate (i.e.,
18000 cfm); thus, there is no impact on either the 10 CFR 20 or 10 CFR 100 dose analyses.
Therefore, these proposed changes do not significantly increase the consequences of an accident previously evaluated.
This proposed change does not create the possibility of a new or different kind of accident from an accident previously evaluated.
The proposed permanent changes do not affect the allowable statuses of any of the reactor zones or the refueling zone.
The proposed temporary changes allow for the following Unit 3 reactor zone statuses:
1.
Reactor defueled and not requi.red for secondary containment integrity, or 2.
Reactor defueled but required for secondary containment integrity If Unit 3 is defueled and the Unit 3 secondary containment zone is not needed for operation of Unit 2, there is no requirement to maintain secondary containment in Unit 3 and no impact on the operability of secondary containment for the unit(s) requiring secondary containment.
While the Unit 3 reactor is defueled, the Unit 3 secondary containment may be desired or required in order to maintain a qualified boundary entirely around a fueled reactor (i.e., qualified inter-zonal wall not maintained).
In this event, the plant must return to a four zone secondary containment.
The temporary change ensures the operability of a Secondary Containment boundary for the operating unit (Unit 2) and will reinstate it before loading fuel in Unit 3.
The Unit 1 secondary containment is considered a part of the Unit 2 boundary.
Therefore, these proposed changes do not create the possibility of a new or different kind of accident from an accident previously evaluated.
Page 3 of 3 ENCLOSURE 4 (ComzwuEo)
BROMNS FERRY NUCLEAR PLANT (BFN)
PROPOSED DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATION 3.
These proposed temporary and permanent changes do not involve a significant reduction in a margin of safety.
Secondary containment integrity can be satisfied by having multiple zones forming a qualified secondary containment boundary entirely around the unit(s) requiring secondary containment.
The addition of a statement to allow a unit reactor zone to be isolated from the secondary containment boundary is consistent with the definition requirements for secondary containment integrity and will not interfere with the ability of the plant to achieve a secondary containment boundary where required.
Therefore, this proposed change does not involve a significant reduction in a margin of safety.
Determination of Basis for Pro osed No Si nificant Hazards Since the application for amendment involves a proposed change that is encompassed by the criteria for which no significant hazards consideration
- exists, TVA has made a proposed determination that the application involves no significant hazards consideration.