ML18033A259

Proposed Tech Specs Revs Clarifying Limiting Conditions for Operation for RHR Svc Water & Emergency Equipment Cooling Water

ML18033A259
Person / Time
Site:	Browns Ferry
Issue date:	06/24/1988
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML18033A258	List: ML18033A257 ML18033A259
References
TVA-BFN-TS-242, NUDOCS 8807050531
Download: ML18033A259 (16)

Text

ENCLOSURE 1 PROPOSED TECHNICAL SPECIFICATIONS REVISIONS BROWNS FERRY NUCLEAR PLANT UNITS 1, 2, AND 3 (TVA BFN TS 242) 880705053i 880624 PDR ADOCK 05000259 P PDC

ENCLOSURE 2 DESCRIPTION AND JUSTIFICATION BRONNS FERRY NUCLEAR PLANT Descri tion of Chan e The Browns Ferry Nuclear Plant (BFN) Units 1, 2, and 3 Technical Specifications, Section '3.5.C, including Table 3.5-1 and the Bases, are revised to clarify the limiting conditions for operation for the Residual Heat Removal Service Hater (RHRSW) and Emergency Equipment Cooling Hater (EECN) Systems. Specifically:

l. 3.5.C.l is rewritten to refer the user to table 3.5-1 for RHRSN pump operability requirements prior to startup from a cold shutdown condition.

2. Table 3.5-1 is amended to address minimum service requirements prior to startup from a cold shutdown condition, to allow reduction by one of the number of RHRSN pumps required to be operable when the decay heat load can be handled by one RHR heat exchanger during shutdown, and to reformat.

3. 3.5.C (Bases) is amended to state that the entire shutdown cooling load is capable of being handled by one RHR heat exchanger after decay heat levels have decreased following shutdown.

Reason for Chan e The present technical specifications are restrictive in two areas: (1) nine RHRSN pumps are required to be operable prior to startup of a unit regardless of the number of fueled units and (2) two RHRSN pumps assigned to RHR heat exchanger duty per fueled unit, plus one for single failure protection, are required to be operable regardless of the decay heat loads in a shutdown unit. The proposed changes will increase operational flexibility.

Administrative changes are being made to provide a title for table 3.5-1 and to use alphabetical instead of numerical characters to designate the notes for the table in order to avoid confusion.

Justification for Chan e

1. The present bases accurately indicate that two RHR heat exchangers, and thus two RHRSN pumps, "can more than adequately handle the cooling requirements of one unit in any abnormal or postaccident situation."

Therefore, requiring that seven RHRSH pumps be assigned to service on the RHR heat exchangers, even though only one or two units are fueled, is overly restrictive. By allowing the plant to reduce the number of required operable RHRSH pumps in accordance with the number of defueled units, the safe operation of the plant will not be affected and the technical specifications for startup of a unit will be consistent with power operation of the unit.

Justification for Chan e (Cont'd)

2. The bases are amended to note that sometime after reactor shutdown, the decay heat level decreases to a point that only one RHR heat exchanger is required to provide cooling. This is consistent with section 4.8.B.l of the Browns Ferry Final Safety Analysis Report (FSAR). With only one RHR heat exchanger required, the number of RHRSW pumps required can be reduced by one for each unit when fuel is in the reactor vessel after the reactor has been shutdown for 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> without affecting the safe operation of the plant.

3. The administrative changes do not change actual technical specification requirements, but provide consistency in the technical specifications.

ENCLOSURE 3 DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATION BRONNS FERRY NUCLEAR PLANT UNITS 1, 2, AND 3 Descri tion of Amendment The proposed amendment would modify the Browns Ferry Nuclear Plant Technical Specifications (Section 3.5.C, including Bases and Table 3.5-1) for units 1, 2, and 3 to:

1. Allow a reduction by two per defueled unit of the number of RHRSH pumps required to be operable before to restart of a shutdown unit,

2. Allow a reduction by one of the number of RHRSN pumps required to be operable for each shutdown unit still containing fuel when the decay heat level has decreased to a point where one RHR heat exchanger can handle the load.

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 considerations 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, or (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.

1. Reducing the number of RHRSH pumps as proposed will not involve a significant increase in the probability or consequences of an accident previously evaluated. This proposed change is only applicable for specific shutdown conditions and specific conditions prior to reactor heatup.

A review of the General Electric Residual Heat Removal System (GE RHR)

Design Specification Revision 3 for various reactor shutdown conditions was performed. This review identified that 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> after reactor shutdown, decay heat has decreased to a level such that two RHRSH pumps will maintain adequate cooling capability. A specific maximum decay heat load analysis shows that 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> after reactor shutdown the decay heat is approximately 12.5 MNt. A RHR heat exchanger was determined (GE RHR Design Specification Revision 3) to be able to provide 44 by (12.89 MHt) cooling capacity during the shutdown mode. Based on 10'tu/hour this analysis, BFN Technical Specification Table 3.5-1(e) reduces the minimum pump requirements by one RHRSN pump per fueled unit required to be operable 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> after shutdown. This will still require at least two RHRSN pumps to be operable to provide adequate cooling capacity for decay heat removal requirements and single failure criteria. BFN FSAR Section 4.8.6.1 states "During a nuclear system shutdown and cooldown,

Basis for Pro osed No Si nificant Hazards Consideration Determination (Cont'd) when the shutdown cooling subsystem is initially placed in operation, decay heat levels can be high and operation of two RHR heat exchangers may be required to remove the heat. Nhen the decay heat level has decreased sufficiently, exchanger' the entire shutdown cooling load can be handled by one RHR heat The current technical specifications and bases address reactor cooling requirements for reactor shutdown after being at power operation for steady state, abnormal, or postaccident conditions. The proposed change will not affect the re.liability of this system. Reducing the number of RHRSN pumps required to be operable 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> after reactor shutdown is still within the envelope of the heat removal capability of the RHR System.

For restart of a unit that has been shutdown for at least 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br />, the same analysis applies. However, once reactor heatup is initiated, additional RHRSN pumps will be started in accordance with table 3.5-1. In any event, a minimum of two RHRSN pumps will be maintained operable at all times to support the maximum possible decay heat removal requirements as .

specified by TVA calculations and to meet single failure criteria. Since this change does not alter or reduce the operation of the system, it wi 11 still perform its intended safety function and therefore does not create a significant increase in an accident previously evaluated.

2. This proposed change does not create the possibility of a new or different kind of accident from any previously evaluated. This proposed change is still within the bounds of the design of the system. Although the proposed technical specification allows'a reduction in the number of RHRSN pumps required to be operable during a specific operating condition, adequate water supply will still be available in order for the system to perform its intended safety function. This proposed change does not alter the operation or function of the RHRSN System.

3. This proposed change does not involve a significant reduction in a margin of safety. It does not change or alter the required safety functions of the RHRSN System, nor does it physically modify any equipment, setpoints, or initiating time/sequence of the equipment.

Single failure criteria requires that two operable RHRSN pumps be powered from separate emergency electrical power sources. If in event of a loss of offsite power and a failure of the diesel generator powering one of the RHRSN pumps, the second pump is available to maintain the required cooling capacity. This proposed change accounts for the single failure criteria.

This change does not require any equipment modifications; therefore, there are no changes to the seismic or environmental qualification requirements associated with these systems.

Basis for Pro osed No Si nificant Hazards Consideration Determination (Cont'd)

Since this proposed technical specification does not alter any of the design basis, safety analysis, or functions of any safety related equipment, there is no reduction in the margin of safety.

3.5/4.5 CORE AND CONTAINMENT COOLING SYSTEMS LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS 3.5.C RHR Service Water and Emer enc 4.5.C RHR Service Water and Emer enc E ui ment Coolin Water S stems E ui ment Coolin Water S stems (EECWS) (EECWS)

l. Prior to STARTUP from a l. a. Each of the RHRSW pumps COLD SHUTDOWN CONDITION, normally assigned to the RHRSW pumps, including automatic service on pump Dl or D2, shall be the EECW headers will OPERABLE and assigned to be tested service as indicated in automatically each time Table 3.5-1. the diesel generators are tested. Each of the RHRSW pumps and all associated essential control valves for the EECW headers and RHR heat exchanger headers shall be demonstrated to be .

OPERABLE once every three months.

b. Annually each RHRSW pump shall be flow-rate tested. To be considered OPERABLE, each pump shall pump at least 4500 gpm through its normally assigned flow path.

BFN 3.5/4.5-9 Unit 1

TABLE 3.5-1 MINIMUM RHRSW AND EECW PUMP ASSIGNMENT Time Minimum Mi nimum Limi t Number Of Number of (Da s) RHRSW EECW~8 (D)(E) (A)

Indefinite 7 3 (C) (D) (E) (F) (A)(C)(F) 30 7 or 6 2or3 (D)(E) (A) 6 2 (A) At least one operable pump must be assigned to each header.

(B) Only automatically starting pumps may be assigned to EECW header service.

(C) Nine pumps must be operable. Either configuration is acceptable:

7 and 2 or 6 and 3 (except as reduced by notes D and E).

(D) Requirements may be reduced by two for each unit with fuel unloaded.

(E) For units with fuel loaded, the minimum RHRSW pump. requirements may be reduced by one pump for each unit that has been in COLD SHUTDOWN CONDITION for more than 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br />. At least 2 of the required pumps must be powered from separate'electric power sources with their associated RHR pumps, heat exchangers, and diesel generator(s)

OPERABLE.

(F) These minimum service requirements are also applicable to startup from a COLD SHUTDOWN CONDITON.

BFN 3.5/4.5-11 Unit 1

3.5 Bases (Cont'd)

The suppression chamber can be drained when the reactor vessel pressure is atmospheric, irradiated fuel is in the reactor vessel, and work is not in progress which has the potential to drain the vessel. By requiring the fuel pool gate to be open with the vessel head removed, the combined water inventory in the fuel pool, the reactor cavity, and the separator/dryer pool, between the fuel pool low level alarm and the reactor vessel flange, is about 65,800 cubic feet (492,000 gallons).

This will provide adequate low-pressure cooling in lieu of CSS and RHR (LPCI and containment cooling mode) as currently required in Specifications 3.5.A.4 and 3.5.B.9. The additional requirements for providing standby coolant supply available will ensure a redundant supply of coolant supply. Control rod drive maintenance may continue during this period provided no more than one drive is removed at a time unless blind flanges are installed during the period of time CRDs are not in place.

Should the capability for providing flow through the cross-connect lines be lost, a 10-day repair time is allowed before shutdown is required. This repair time is justified based on the very small probability for ever needing RHR pumps and heat exchangers to supply an adjacent unit.

REFERENCES

1. Residual Heat Removal System (BFNP FSAR subsection 4.8)

2. Core Standby Cooling Systems (BFNP FSAR Section 6) 3.5.C. RHR Service Water S stem and Emer enc E ui ment Coolin Water S stem (EECWS)

The EECW has two completely redundant and independent headers (north and south) in a loop arrangement inside and outside the Reactor Building. Each header is supplied by two automatic RHRSW pumps. A crosstie at the RHRSW pump discharge provides the capability for each header to be supplied by four automatically starting RHRSW pumps.

Those components requiring EECW, except the control air compressors, are able to be fed from both headers thus assuring continuity of operation if either header becomes inoperable. The air compressors only use EECW as an emergency backup supply.

There are four RHR heat exchanger headers (A, B, C, 5 D) with one RHR heat exchanger from each unit: on each header. There are two RHRSW-pumps on each header; one normally assigned to each header (A2, B2, C2, or D2) and one on alternate assignment (Al, Bl, Cl, or Dl). One RHR heat exchanger header can adequately deliver the flow supplied by both RHRSW pumps to any two of the three RHRSW heat exchangers on the header, One RHRSW pump can supply the full flow requirement of one RHR heat exchanger. Two RHR heat exchangers can more than adequately handle the cooling requirements of one unit in any abnormal or postaccident situation. When the decay heat level has decreased sufficiently following shutdown, the entire shutdown cooling load can be adequately handled by one RHR heat exchanger.

BFN 3.5/4.5-28 Unit 1

3.5/4.5 CORE AND CONTAINMENT COOLING SYSTEMS LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS 3.5.C RHR Service Water and Emer enc 4.5.C RHR Service Water and Emer enc E ui ment Coolin Water S stems E ui ment Coolin Water S stems (EECWS) (EECWS)

1. Prior to STARTUP from a 1. a. Each of the RHRSW pumps COLD SHUTDOWN CONDITION, normally assigned to the RHRSW pumps, (including automatic service on one of pumps Dl, D2, B2 the EECW headers wi 11 or Bl) shall be OPERABLE be tested and assigned to service automatically each time as indicated in Table 3.5-1. the diesel generators are tested. Each of the RHRSW pumps and all ~

associated essential control valves for the EECW headers and RHR heat exchanger headers shall be demonstrated to be OPERABLE once every three months.

b. Annually each RHRSW pump shall be flow-rate tested. To be considered OPERABLE, each pump shall pump at least 4500 gpm through its normally assigned flow path.

BFN 3.5/4.5-9 Unit 2

TABLE 3.5-1 MINIMUM RHRSW AND EECW PUMP ASSIGNMENT Time Minimum Minimum Limi t Number Of Number of (Da s) RHRSW EECW~8 (D) (E) (A)

Indefinite 7 3 (C)(D)(E)(F) (A)(C)(F) 30 7 or.6 2or3 (D)(E) (A) 6 2 (A) At least one operable pump must be assigned to each header.

(B) Only automatically starting pumps may be assigned to EECW header service.

(C) Nine pumps must be operable. Either configuration is acceptable:

7 and 2 or 6 and 3 (except as reduced by notes D and E).

(D) Requirements may be reduced by two for each unit with fuel unloaded.

(E) For units with fuel loaded, the minimum RHRSW pump requirements may be reduced by one pump for each unit that has been in COLD SHUTDOWN CONDITION for more than 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br />. At least 2 of the required pumps must be powered from separate electric power sources with their associated RHR pumps, heat exchangers, and diesel generator(s)

OPERABLE.

(F) These minimum service requirements are also applicable to startup from a COLD SHUTDOWN CONDITON.

BFN 3.5/4.5-11 Unit 2

~

3.5 Bases (Cont'd)

The suppression chamber can be drained when the reactor vessel pressure is atmospheric, irradiated fuel is in the reactor vessel, and work is not in progress which has the potential to drain the vessel. By requiring the fuel pool gate to be open with the vessel head removed, the combined water inventory in the fuel pool, the reactor cavity, and the separator/dryer pool, between the fuel pool low level alarm and the reactor vessel flange, is about 65,800 cubic feet (492,000 gallons).

This will provide adequate low-pressure cooling in lieu of CSS and RHR (LPCI and containment cooling mode) as currently required in Specifications 3.5.A.4 and 3.5.8.9. The additional requirements for providing standby coolant supply available wi 11 ensure a redundant supply of coolant supply. Control rod drive maintenance may continue during this period provided no more than one drive is removed at a time unless blind flanges are installed during the period of time CRDs are not in place.

Should the capability for providing flow through the cross-connect lines be lost, a 10-day repair time is allowed before shutdown is required. This repair time is justified based on the very small probability for ever needing RHR pumps and heat exchangers to supply an adjacent unit.

REFERENCES

1. Residual Heat Removal System (BFNP FSAR subsection 4.8)

2. Core Standby Cooling Systems (BFNP FSAR Section 6) 3.5.C. RHR Service Hater S stem and Emer enc E ui ment Coolin Hater S stem (EECNS)

The EECN has two completely redundant and independent headers (north and south) in a loop arrangement inside and outside the Reactor Building. Each header is supplied by two automatic RHRSN pumps. A crosstie at the RHRSN pump discharge provides the capability for each header to be supplied by four automatically starting RHRSN pumps.

those components requiring EECW, except the control air compressors, are able to be fed from both headers thus assuring continuity of operation if either header becomes inoperable. The air compressors only use EECN as an emergency backup supply.

There are four RHR heat exchanger headers (A, B, C, & D) with one RHR heat exchanger from each unit on each header. There are two RHRSN pumps on each header; one normally assigned to each header (A2, B2, C2, or D2) and one on alternate assignment (Al, Bl, Cl, or Dl). One Rf)R heat exchanger header can adequately deliver the flow supplied by both RHRSN pumps to any two of the three RHRSN heat exchangers on the header. One RHRSN pump can supply the full flow requirement of one RHR heat exchanger. Two RHR heat exchangers can more than adequately handle the cooling requirements of one unit in any abnormal or postaccident situation. Nhen the decay heat level has decreased sufficiently following shutdown, the entire shutdown cooling load can be adequately handled by one RHR heat exchanger.

BFH 3.5/4.5-26 Unit 2

3 ~ 5/4.5 CORE AND CONTAINMENT COOLING SYSTEMS LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS 3.5.C RHR Service Hater and Emer enc 4.5.C RHR Service Hater and Emer enc E ui ment Coolin Hater S stems E ui ment Coolin Hater S stems (EECWS) (EECWS)

1. Prior to STARTUP from a 1. a. Each of the RHRSH pumps COLD SHUTDONN CONDITION, normally assigned to the RHRSN pumps, including automatic service on pump Bl or B2, shall be the EECN headers will OPERABLE and assigned to be tested service as indicated in automatically each time Table 3.5-1. the diesel generators are tested. Each of the RHRSN pumps and all associated essential control valves for the EECW headers and RHR heat exchanger headers shall be demonstrated to be OPERABLE once every three months.

b. Annually each RHRSN pump shall be flow-rate tested. To be considered OPERABLE, each pump shall pump at least 4500 gpm through its normally assigned flow path.

BFN-Unit 3 3.5/4.5-9

TABLE 3.5-1 MINIMUM RHRSN AND EECH PUMP ASSIGNMENT Time Minimum Minimum Limit Number Of Number of (Da s) RHRSN E ECHE (D)(E) (A)

Indefinite 7 3 (C)(D)(E)(F) (A)(C)(F) 30 7 or 6 2ol 3 (D)(E) (A) 6 2 (A) At least one operable pump must be assigned to each header.

(8) Only automatically starting pumps may be assigned to EECH header service.

(c) Nine pumps must be operable. Either configuration is acceptable:

7 and 2 or 6 and 3 (except as reduced by notes D and E).

(D) Requirements may be reduced by two for each unit with fuel unloaded.

(E) For units with fuel loaded, the minimum RHRSH.pump requirements may be reduced by one pump for each unit that has been in COLD SHUTDONN CONDITION for more than 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br />. At least 2 of the required pumps must 'be powered from separate electric power sources wi th their associated RHR pumps, heat exchangers, and diesel generator(s)

OPERABLE.

(F) These minimum service requirements are also applicable to startup from a COLD SHUTDOHN CONDITON.

BFN-Unit 3 3.5/4.5-11

3.5 Bases (Cont'd)

The suppression chamber can be drained when the reactor vessel pressure is atmospheric, irradiated fuel is in the reactor vessel, and work is not in progress which has the potential to drain the vessel. By requiring the fuel pool gate to be open with the vessel head removed, the combined water inventory in the fuel pool, the reactor cavity, and the separator/dryer pool, between the fuel pool low level alarm and the reactor vessel flange, is about 65,800 cubic feet (492,000 gallons).

This will provide adequate low-pressure cooling in lieu of CSS and RHR (LPCI and containment cooling mode) as currently required in Specifications 3.5.A.4 and 3.5.B.9. The additional requirements for providing standby coolant supply available will ensure a redundant supply of coolant supply. Control rod dr,ive maintenance may continue during this period provided no more than 'one drive is removed at a time unless blind flanges are installed during the period of time CRDs are not in place.

Should the capability for providing flow through the cross-connect lines be lost, a 10-day repair time is allowed before shutdown is required. This repair time is justified based on the very small probability for ever needing RHR pumps and heat exchangers to supply an adjacent unit.

REFERENCES

1. Residual Heat Removal System (BFNP FSAR subsection 4.8)

~

2. Core Standby Cooling Systems (BFNP FSAR Section 6) 3.5.C. RHR Service Nater S stem and Emer enc E ui ment Coolin Hater S stem (EECNS)

The EECW has two completely redundant and independent headers (north and south) in a loop arrangement inside and outside the Reactor Building. Each header is supplied by two automatic RHRSN pumps. A crosstie at the RHRSN pump discharge provides the capability for each header to be supplied by four automatically starting RHRSN pumps.

those components requiring EECN, except the control air compressors, are able to be fed from both headers thus assuring continuity of operation if either header becomes inoperable. The air compressors only use EECN as an emergency backup supply.

There are four RHR heat exchanger headers (A, B, C, II D) with one RHR heat exchanger from each unit on each header. There are two RHRSN pumps on each header; one normally assigned to each header (A2, B2, C2, or D2) and one on alternate assignment (Al, Bl, Cl, or Dl). One RHR heat exchanger header can adequately deliver the flow supplied by both RHRSN pumps to any two of the three RHRSN heat exchangers on the header. One RHRSN pump can supply the full flow requirement of one RHR heat exchanger. Two RHR heat exchangers cari more than adequately handle the cooling requirements of one unit in any abnormal or postaccident situation. Nhen the decay heat level has decreased sufficiently following shutdown, the entire shutdown cooling load can be adequately handled by one RHR heat exchanger.

BFN-Unit 3 3.5/4.5-29