View source for BSEP 06-0136, Request for License Amendment, Technical Specification 3.4.1, Recirculation Loops Operating Recirculation Loop Operating Requirements.

{{Adams
| number = ML063620105
| issue date = 12/21/2006
| title = Request for License Amendment, Technical Specification 3.4.1, Recirculation Loops Operating Recirculation Loop Operating Requirements.
| author name = Scarola J
| author affiliation = Progress Energy Co
| addressee name = 
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000324, 05000325
| license number = DPR-062, DPR-071
| contact person = 
| case reference number = BSEP 06-0136, TSC-2006-04
| document type = Letter type:BSEP, License-Application for Facility Operating License (Amend/Renewal) DKT 50, Technical Specifications
| page count = 24
| project = 
| stage = Request
}}

=Text=
{{#Wiki_filter:James Scarola Vice President Brunswick Nuclear Plant Progress Energy Carolinas, Inc.December 21, 2006 SERIAL: BSEP 06-0136 10 CFR 50.90 TSC-2006-04 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

==Subject:==
Brunswick Steam Electric Plant, Unit Nos. 1 and 2 Docket Nos. 50-325 and 50-324/License Nos. DPR-71 and DPR-62 Request for License Amendment Technical Specification 3.4.1, "Recirculation Loops Operating" Recirculation Loop Operating Requirements Ladies and Gentlemen:
In accordance with the Code of Federal Regulations, Title 10, Part 50.90, Carolina Power & Light Company (CP&L), now doing business as Progress Energy Carolinas, Inc., is requesting a revision to the Technical Specifications (TSs) for the Brunswick Steam Electric Plant (BSEP), Unit Nos. 1 and 2. The proposed license amendment revises TS 3.4.1, "Recirculation Loops Operating," to require the recirculation loops be operated with matched flows versus recirculation pump speeds as currently required.
This change affects the Limiting Condition for Operation (LCO) requirements and Surveillance Requirements of TS 3.4.1. An evaluation of the proposed license amendment is provided in Enclosure 1.CP&L has evaluated the proposed change in accordance with 10 CFR 50.91(a)(1), using the criteria in 10 CFR 50.92(c), and determined that this change involves no significant hazards considerations.
CP&L is providing, in accordance with 10 CFR 50.9 1(b), a copy of the proposed license amendment to the designated representative for the State of North Carolina.CP&L requests approval of the proposed amendment by August 31, 2007, and that once approved, the amendment shall be implemented within 90 days.No regulatory commitments are contained this submittal.
Please refer any questions regarding this submittal to Mr. Randy C. Ivey, Manager -Support Services, at (910) 457-2447.P.O. Box 10429 Southport, NC 28461 T> 910.457.3698 -A F> 910.457.2803 Document Control Desk BSEP 06-0136 / Page 2 I declare, under penalty of perjury, that the foregoing is true and correct. Executed on December 21, 2006.Sincerely, tJames Scarola MAT/mat 

==Enclosures:==
: 1. Evaluation of License Amendment Request 2. Marked-up Technical Specification Pages -Unit 1 3. Typed Technical Specification Pages -Unit 1 4. Typed Technical Specification Pages -Unit 2 5. Marked-up Technical Specification Bases Pages -Unit 1 (For Information Only)
Document Control Desk BSEP 06-0136 / Page 3 cc (with enclosures):
U. S. Nuclear Regulatory Commission, Region II ATTN: Dr. William D. Travers, Regional Administrator Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, GA 30303-8931 U. S. Nuclear Regulatory Commission ATTN: Mr. Eugene M. DiPaolo, NRC Senior Resident Inspector 8470 River Road Southport, NC 28461-8869 U. S. Nuclear Regulatory Commission (Electronic Copy Only)ATTN: Ms. Brenda L. Mozafari (Mail Stop OWFN 8G9)11555 Rockville Pike Rockville, MD 20852-2738 Ms. Jo A. Sanford Chair -North Carolina Utilities Commission P.O. Box 29510 Raleigh, NC 27626-0510 Ms. Beverly 0. Hall, Section Chief Radiation Protection Section, Division of Environmental Health North Carolina Department of Environment and Natural Resources 3825 Barrett Drive Raleigh, NC 27609-7221 BSEP 06-0136 Enclosure 1 Page 1 of 7 Evaluation of Proposed License Amendment Request 

==Subject:==
Technical Specification 3.4.1, "Recirculation Loops Operating" Recirculation Loop Operating Requirements 1.0 Description This letter is a request to amend Renewed Operating Licenses DPR-71 and DPR-62 for the Brunswick Steam Electric Plant (BSEP), Unit Nos. 1 and 2.The proposed change revises Technical Specification (TS) 3.4.1, "Recirculation Loops Operating," to require the recirculation loops be operated with matched flows versus recirculation pump speeds as currently required.
During conversion of the BSEP TSs to the Improved Technical Specifications, as contained in Revision 1 of NUREG-1433, "Standard Technical Specifications General Electric Plants, BWR/4," a more restrictive change was made to require that operating recirculation loops be matched with respect to recirculation pump speeds. This deviated from the wording for Revision 1 of NUREG-1433, in that the NUREG required the loops be matched with respect to flows rather than pump speed. The Improved Technical Specifications were approved for BSEP Units 1 and 2 in Amendments 203 and 233, respectively, on June 5, 1998. Previous to conversion, the BSEP TSs required that two recirculation loops be in operation with no specific requirement for matching of flows or pump speeds. The change in nomenclature was made for operator convenience.
Recirculation pump speed indication is readily available to the control room operators; whereas recirculation loop jet pump flow indication is not. As such, pump speed was chosen as the means to verify recirculation loop flow matching.
Subsequently, it has been determined that pump speed requirements, established in Surveillance Requirement (SR) 3.4.1.1, are not sufficiently conservative.
To remedy this condition, the Limiting Condition for Operation (LCO)requirements of TS 3.4.1 and SR 3.4.1.1 are being revised to require matched recirculation loop jet pump flow, consistent with NUREG-1433.
This condition was discovered on October 27, 2006, and is documented in Nuclear Condition Report 210701. Consistent with the guidance provided in Administrative Letter 98-10,"Disposition of Technical Specifications That Are Insufficient to Assure Plant Safety," dated December 29, 1998, administrative controls have been established to confirm recirculation loop jet pump flows are matched as well as complying with the existing SR 3.4.1.1 requirements.
Plant procedure OPT-13.5, "Reactor Recirculation Pump Differential Speed and Loop Flow Check," was issued, on October 27, 2006, to include the loop flow surveillance requirements.
2.0 Proposed Change The proposed change revises LCO 3.4.1 to require that two recirculation loops with matched flows be in operation.
Currently, LCO 3.4.1 requires that the two recirculation loops have matched recirculation pump speeds. As a result of the revised LCO, SR 3.4.1.1 is being revised BSEP 06-0136 Enclosure 1 Page 2 of 7 to require verification of matched recirculation loop jet pump flows. The specific wording of the proposed changes follows.Existing Requirement Proposed Requirement LCO 3.4.1 Two recirculation loops with matched LCO 3.4.1 Two recirculation loops with matched recirculation pump speeds shall be in flows shall be in operation.
operation.
SR 3.4. 1.1 ---------------
NOTE --------------
SR 3.4.1.1 ---------------
NOTE -----------
Not required to be performed until Not required to be performed until 24 hours after both recirculation loops 24 hours after both recirculation loops are in operation.
are in operation.
Verify the following recirulation pump Verify recirculation loop jet pump flow speed match criteria are satisfied:
mismatch with both recirculation loops a. The recirculation pump speeds are in operations is:< 20% of each other when operating
: a. < 10% of rated core flow when at < 75% of rated core flow; and operating at < 75% of rated core b. The recirculation pump speeds are flow; and< 10% of each other when operating
: b. < 5% of rated core flow when at ? 75% of rated core flow. operating at _> 75% of rated core flow.In summary, the overall affect of the proposed amendment is to implement more conservative requirements associated with recirculation loop operation.
These requirements assure that the mismatch between recirculation loop flows remains bounded by existing design bases analyses.These changes are consistent with the current version of the Standard Technical Specifications (i.e., Reference 1: NUREG-1433, Revision 3.1).For convenience, Enclosure 2 contains a marked-up version of the Unit 1 TSs showing the proposed changes. Since TS Sections 3.4.1 for Unit 1 and Unit 2 are identical, only the mark-up for Unit 1 is provided.
Enclosures 3 and 4 provide typed versions of the Unit 1 and Unit 2 TSs, respectively.
These typed TS pages are to be used for issuance of the proposed amendment.
Carolina Power & Light Company (CP&L), now doing business as Progress Energy Carolinas, Inc., will make supporting changes to the TS Bases in accordance with TS 5.5.10, "Technical Specifications (TS) Bases Control Program." Enclosure 5 provides marked-up TS Bases pages for Unit 1. These pages are being submitted for information only and do not require issuance by the NRC.
BSEP 06-0136 Enclosure 1 Page 3 of 7 3.0 Background System Description/Applicable Safety Analysis The Reactor Recirculation system is designed to provide a forced coolant flow through the core to remove heat from the fuel. The operation of the Reactor Recirculation system is an initial condition assumed in the design basis loss of coolant accident (LOCA). During a LOCA caused by a recirculation loop pipe break, the intact loop is assumed to provide coolant flow during the first few seconds of the accident.
The initial core flow decrease is rapid because the recirculation pump in the broken loop ceases to pump reactor coolant to the vessel almost immediately.
The pump in the intact loop coasts down relatively slowly. This pump coastdown governs the core flow response for the next several seconds until the jet pump suction is uncovered.
The LOCA analysis assumes that both loops are operating at the same flow prior to the accident.
However, the LOCA analysis was reviewed for the case with a flow mismatch between the two loops, with the pipe break assumed to be in the loop with the higher flow. While the flow coastdown and core response are potentially more severe in this assumed case (i.e., since the intact loop starts at a lower flow rate and the core response is the same as if both loops were operating at a lower flow rate), a small mismatch has been determined to be acceptable based on engineering judgment.
The recirculation system is also assumed to have sufficient flow coastdown characteristics to maintain fuel thermal margins during abnormal operational transients.
Need for Change On October 27, 2006, as documented in Nuclear Condition Report 210701, CP&L determined that the existing SR 3.4.1.1, which verifies that recirculation pumps speeds are within 20% of each other when operating at less that 75% of rated core flow or within 10% of each other when operating at greater than or equal to 75% of rated core flow, does not provide adequate assurance that the recirculation loops are operating within the initial conditions of the existing LOCA analysis.
To be bounded by the existing LOCA analysis, SR 3.4.1.1 must verify that for core flows less than 75% of rated, the loop flows shall be within 10% of rated core flow and for flows greater than or equal to 75% of rated, the loop flows shall be within 5% of rated core flow.4.0 Technical Analysis The intent of LCO 3.4.1 and SR 3.4.1.1 is to ensure that the Reactor Recirculation system is operated within the bounds of the existing LOCA analysis, which assumes that both loops are operating at essentially the same flow prior to an accident.
For BSEP, GE Nuclear Energy has determined (i.e., Reference
: 2) that the LOCA analysis assumption is met, for core flows less than 75% of rated, when the recirculation loop flows are operating within 10% of rated core flow and, for flows greater than or equal to 75% of rated, when the recirculation loop flows are within 5%of rated core flow. The same GE Nuclear Energy document indicates that a 5% mismatch in terms of core flow conservatively equates to a 10% mismatch in terms of either loop flow or BSEP 06-0136 Enclosure 1 Page 4 of 7 pump speed. Based on this guidance, the existing LCO 3.41 and SR 3.4.1.1 requirements were established.
In October 2006, Operations personnel noted that for a small indicated difference in recirculation pump speeds the deviation in loop flow was larger than expected.
Based on this observation, Engineering initiated an evaluation of the bases for the criteria established in SR 3.4.1.1. As a result of the evaluation, three concerns were identified with the existing methodology of determining recirculation loop mismatch.
The following discussion addresses each area of concern, from most significant to least significant.
Core Flow to Recirculation Pump Speed Correlation The GE Nuclear Energy guidance indicated that recirculation pump speeds were to be within 20% of each other for core flows less than 75% of rated or within 10% of each other for core flows greater than or equal to 75% of rated. This was based on the determination that a 5%mismatch in terms of core flow conservatively equates to a 10% mismatch in terms of recirculation pump speed. For this 5% core flow to 10% recirculation pump speed correlation to be accurate, the mismatch must be determined based on a ratio of one recirculation pump's speed to the other pump's speed. When SR 3.4.1.1 was implemented at BSEP, the procedure merely subtracted one loop's pump speed from the other loop's pump speed. This effectively doubled the mismatch when equated to core flow.Hydraulic Interaction When the GE Nuclear Energy guidance was issued, a one-to-one relationship between speed and flow was assumed to exist based on the pump affinity relationship, which indicates that as the speed of a pumps is changed, the pump flow change will be proportional and the pump differential pressure (dP) change will be proportional to the square of the change in speed.However, when a small speed mismatch occurs, the interaction between dPs causes a greater than one-to-one flow change. The potential for this hydraulic interaction was not clearly addressed in the GE Nuclear Energy guidance and, as a result, was overlooked by CP&L when developing TS 3.4.1.Scaling The GE Nuclear Energy guidance indicated the potential need for scaling to account for conditions where the recirculation pump speed scale (i.e., 0 to 100% pump speed) is offset from the 0 to 100% rated core flow range. For example, on Unit 1, 86% to 87% recirculation pump speed is required to achieve 100% of rated core flow and, on Unit 2, 94% to 95% recirculation pump speed is required to reach 100% of rated core flow. Again, the scaling issue was not clearly addressed in the GE Nuclear Energy guidance and, as a result, was overlooked by CP&L when developing TS 3.4.1.
BSEP 06-0136 Enclosure 1 Page 5 of 7 Conclusion The above factors resulted in the potential that, although meeting the requirements of SR 3.4.1.1, the operating recirculation loops could, in fact, be outside the bounds of the LOCA analysis with respect to core flow.To remedy this condition, the LCO requirements of TS 3.4.1 and SR 3.4.1.1 are being revised to directly monitor recirculation loop jet pump flows, consistent with the LOCA analysis assumption as well as the current version of the Standard Technical Specifications (i.e., NUREG 1433, Revision 3.1).5.0 Regulatory Safety Analysis 5.1 No Significant Hazards Consideration CP&L has evaluated whether or not a significant hazards consideration is involved with the proposed amendments by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below: 1. Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?
Response:.
No The proposed amendment implements more conservative requirements associated with recirculation loop operation.
Specifically, the LCO requirements of TS 3.4.1 and SR 3.4.1.1 are being revised to directly monitor recirculation loop jet pump flows versus recirculation pump speed, eliminating potential non-conservatism associated with relating recirculation loop jet pump flow to recirculation pump speed. These requirements assure that the mismatch between recirculation loop jet pump flows are bounded by the existing design bases analyses.
As a result, the proposed change ensures that the consequences of a design bases LOCA remain within the existing evaluation.
The proposed change does not involve a physical change to the Reactor Recirculation system, nor does it alter the assumptions of the accident analyses.
Therefore the probability of an accident previously evaluated is not affected.Based on the above, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
: 2. Does the proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?
Response:
No BSEP 06-0136 Enclosure 1 Page 6 of 7 The proposed change does not involve a physical change to the Reactor Recirculation system, nor does it alter the assumptions of the accident analyses.
The implementation of more conservative requirements associated with recirculation loop operation does not introduce any new failure modes. Therefore, the proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.
: 3. Does the proposed change involve a significant reduction in a margin of safety?Response:
No The proposed amendment implements more conservative requirements associated with recirculation loop operation.
These requirements ensure that the Reactor Recirculation system is operated consistent with the initial conditions of the existing design bases analyses.
Since the design bases analyses assumptions are unchanged, the proposed change does not involve a reduction in a margin of safety.Based on the above, CP&L concludes that the proposed amendments present no significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of "no significant hazards consideration" is justified.
5.2 Applicable Regulatory Requirements/Criteria The Commission's regulatory requirements related to the content of the TSs are set forth in Title 10 of the Code of Federal Regulations (10 CFR) Section 50.36, "Technical specifications." This regulation requires that the TS include items in five specific categories.
These categories include (1) safety limits, limiting safety system settings and limiting control settings, (2) limiting LCOs, (3) SRs, (4) design features, and (5) administrative controls.
Additionally, Criterion 2 of 10 CFR 50.36(c)(2)(ii) requires a limiting condition for operation to be established for a process variable, design feature, or operating restriction that is an initial condition of a design-basis accident (DBA) or transient analysis that either assumes the failure of or presents a challenge to the integrity of a fission product barrier. The proposed change ensures that the LCO and SR associated with operation of the Reactor Recirculation system establish conditions that are consistent with the initial conditions assumed in the LOCA analysis.The BSEP design was reviewed for construction under the "General Design Criteria for Nuclear Power Plant Construction" issued for comment by the AEC in July 1967 and is committed to meet the intent of the General Design Criteria (GDC), published in the Federal Register on May 21, 1971, as Appendix A to 10 CFR Part 50.Criterion 10, "Reactor Designs," requires that the reactor core and associated coolant, control, and protective systems be designed with appropriate margins to assure that specified acceptable fuel design limits are not exceeded during normal operation and anticipated operational occurrences.
The proposed change does not affect BSEP's compliance with the intent of BSEP 06-0136 Enclosure 1 Page 7 of 7 GDC 10. Rather, it imposes TS requirements to ensure that the operation of the Reactor Recirculation system is within the bounds of the existing LOCA analysis.
This ensures that fuel design limits are not exceeded during normal operation and anticipated operational occurrences.
6.0 Environmental Considerations A review has determined that the proposed amendment would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or would change an inspection or surveillance requirement.
However, the proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluent that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure.Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment.
7.0 References
: 1. NUREG-1433, Revision 3.1, "Standard Technical Specifications General Electric Plants, BWR/4," dated December 1, 2005.2. Letter (KFC-37-90) from K. F. Cornewll (GE Nuclear Energy) to Bruce Morgan (CP&L),"Final SLO Operational Guideline Summary," dated April 16, 1990.
BSEP 06-0136 Enclosure 2 Marked-up Technical Specification Pages -Unit 1 Recirculation Loops Operating 3.4.1 3.4 REACTOR CC 3.4.1 Recirculation LCO 3.4.1)OLANT SYSTEM (RCS)Loops Operating Two recirculation loops with matched c h ...........
e-' ' d e shall be in operation, OR One recirculation loop may be in operation provided the following limits are applied when the associated LCO is applicable:
: a. LCO 3.2.1, "AVERAGE PLANAR LINEAR HEAT GENERATION RATE (APLHGR)," single loop operation limits specified in the COLR;b. LCO 3.2.2, "MINIMUM CRITICAL POWER RATIO (MCPR)," single loop operation limits specified in the COLR; and c. LCO 3.3.1.1, "Reactor Protection System (RPS) Instrumentation," Function 2.b (Average Power Range Monitors Simulated Thermal Power-High), Allowable Value of Table 3.3.1.1-1 is reset for single loop operation.
APPLICABILITY:
MODES 1 and 2.ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. Requirements of the LCO A.1 Satisfy the requirements of 6 hours not met. the LCO.(continued)
Amendment No.-i$I Brunswick Unit 1 3.4-1 Recirculation Loops Operating 3.4.1 ACTIONS (continued)
CONDITION REQUIRED ACTION COMPLETION TIME B. Required Action and B.1 Be in MODE 3. 12 hours associated Completion Time of Condition A not met.OR No recirculation loops in operation.
Brunswick Unit 1 3.4-2 Amendment BSEP 06-0136 Enclosure 3 Typed Technical Specification Pages -Unit 1 Recirculation Loops Operating 3.4.1 3.4 REACTOR COOLANT SYSTEM (RCS)3.4.1 Recirculation Loops Operating LCO 3.4.1 Two recirculation loops with matched flows shall be in operation, I OR One recirculation loop may be in operation provided the following limits are applied when the associated LCO is applicable:
: a. LCO 3.2.1, "AVERAGE PLANAR LINEAR HEAT GENERATION RATE (APLHGR)," single loop operation limits specified in the COLR;b. LCO 3.2.2, "MINIMUM CRITICAL POWER RATIO (MCPR)," single loop operation limits specified in the COLR; and c. LCO 3.3.1.1, "Reactor Protection System (RPS) Instrumentation," Function 2.b (Average Power Range Monitors Simulated Thermal Power-High), Allowable Value of Table 3.3.1.1-1 is reset for single loop operation.
APPLICABILITY:
MODES 1 and 2.ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. Requirements of the LCO A.1 Satisfy the requirements of 6 hours not met. the LCO.(continued)
Brunswick Unit 1 3.4-1 Amendment No. I Recirculation Loops Operating 3.4.1 ACTIONS (continued)
CONDITION REQUIRED ACTION COMPLETION TIME B. Required Action and B.1 Be in MODE 3. 12 hours associated Completion Time of Condition A not met.OR No recirculation loops in operation.
SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.4.1.1 -----------------------
NOTE----------------
Not required to be performed until 24 hours after both recirculation loops are in operation.
Verify recirculation loop jet pump flow mismatch with 24 hours both recirculation loops in operation:
: a. _< 10% of rated core flow when operating at< 75% of rated core flow; and b. < 5% of rated core flow when operating at> 75% of rated core flow.Brunswick Unit 1 3.4-2 Amendment No. I BSEP 06-0136 Enclosure 4 Typed Technical Specification Pages -Unit 2 Recirculation Loops Operating 3.4.1 3.4 REACTOR COOLANT SYSTEM (RCS)3.4.1 Recirculation Loops Operating LCO 3.4.1 Two recirculation loops with matched flows shall be in operation, I OR One recirculation loop may be in operation provided the following limits are applied when the associated LCO is applicable:
: a. LCO 3.2.1, "AVERAGE PLANAR LINEAR HEAT GENERATION RATE (APLHGR)," single loop operation limits specified in the COLR;b. LCO 3.2.2, "MINIMUM CRITICAL POWER RATIO (MCPR)," single loop operation limits specified in the COLR; and c. LCO 3.3.1.1, "Reactor Protection System (RPS) Instrumentation," Function 2.b (Average Power Range Monitors Simulated Thermal Power-High), Allowable Value of Table 3.3.1.1-1 is reset for single loop operation.
APPLICABILITY:
MODES 1 and 2.ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. Requirements of the LCO A.1 Satisfy the requirements of 6 hours not met. the LCO.(continued)
Brunswick Unit 2 3.4-1 Amendment No.
Recirculation Loops Operating 3.4.1 ACTIONS (continued)
CONDITION REQUIRED ACTION COMPLETION TIME B. Required Action and B.1 Be in MODE 3. 12 hours associated Completion Time of Condition A not met.OR No recirculation loops in operation.
SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.4.1.1 -- -------------
NOTE -.-----------------
Not required to be performed until 24 hours after both recirculation loops are in operation Verify recirculation loop jet pump flow mismatch with 24 hours both recirculation loops in operation:
: a. _< 10% of rated core flow when operating at< 75% of rated core flow; and b. _ 5% of rated core flow when operating at> 75% of rated core flow.Brunswick Unit 2 3.4-2 Amendment No. I BSEP 06-0136 Enclosure 5 Marked-up Technical Specification Bases Pages -Unit 1 (For Information Only)
Recirculation Loops Operating B 3.4.1 BASES APPLICABLE A plant specific LOCA analysis has been performed assuming only one SAFETY ANALYSES operating recirculation loop. This analysis has demonstrated that, in the (continued) event of a LOCA caused by a pipe break in the operating recirculation loop, the Emergency Core Cooling System response will provide adequate core cooling, without the requirement to modify the APLHGR requirements (Ref. 3). However, the COLR may require APLHGR limits to restrict the peak clad temperature for a LOCA with a single recirculation loop operating below the corresponding temperature for both loops operating.
The transient analyses of Chapter 15 of the UFSAR have also been performed for single recirculation loop operation (Ref. 3) and demonstrate sufficient flow coastdown characteristics to maintain fuel thermal margins during the abnormal operational transients analyzed without the requirement to modify the MCPR requirements.
During single recirculation loop operation, modification to the Reactor Protection System (RPS) average power range monitor (APRM) Simulated Thermal Power-High Allowable Value is required to account for the different analyzed limits between two-recirculation drive flow loop operation and operation with only one loop. The APRM channel subtracts the AW value from the measured recirculation drive flow to effectively shift the limits and uses the adjusted recirculation drive flow value to determine the APRM Simulated Thermal Power-High Function trip setpoint.Recirculation loops operating satisfies Criterion 2 of 10 CFR 50.36(c)(2)(ii) (Ref. 4).LCO Two recirculation loops are normally required to be in operation with their___,_' -matched within the limits specified in SR 3.4.1.1 to ensure that during a LOCA caused by a break of the piping of one recirculation loop the assumptions of the LOCA analysis are satisfied.
Alternately, with only one recirculation loop in operation, modifications to the required APLHGR limits (LCO 3.2.1, "AVERAGE PLANAR LINEAR HEAT GENERATION RATE (APLHGR)"), MCPR limits (LCO 3.2.2, "MINIMUM CRITICAL POWER RATIO (MCPR)"), and APRM Simulated Thermal Power-High Allowable Value (LCO 3.3.1.1), as (continued)
Revision No. -3,P Brunswick Unit 1 B 3.4.1-3 Recirculation Loops Operating B 3.4.1 BASES LCO applicable, must be applied to allow continued operation.
The COLR (continued) defines adjustments or modifications required for the APLHGR and MCPR limits for the current operating cycle.APPLICABILITY In MODES 1 and 2, requirements for operation of the Reactor Coolant Recirculation System are necessary since there is considerable energy in the reactor core and the limiting design basis transients and accidents are assumed to occur.In MODES 3, 4, and 5, the consequences of an accident are reduced and the coastdown characteristics of the recirculation loops are not important.
ACTIONS A.1 With the requirements of the LCO not met, the recirculation loo s must be acientordt ocrering wuingthi mtimhedlpGieriodon pumpasonabletime t complte te ReqiredActio (i~., reet t e oa apTiabe '-paptvso shetpit hould a LOCA occur with one recirculation loop not in operation, the core flow coastdown and resultant core response may not be bounded by the LOCA analyses.
Therefore, only a limited time is allowed to restore the inoperable loop to operating status.Alternatively, if the single loop requirements of the LCO are applied to operating limits and RPS setpoints, as applicable, operation with only one recirculation loop would satisfy the requirements of the LCO and the initial conditions of the accident sequence.The 6 hour Completion Time is based on the low probability of an accident occurring during this time period, on a reasonable time to complete the Required Action (i.e., reset the applicable limits or setpoints for single recirculation loop operation), and on frequent core monitoring by operators allowing abrupt changes in core flow conditions to be quickly (continued)
~0 +/-p ~ {~t~ o-f f4e b&io Brunswick Uni 1t B 3..- evso o Brunswick Unit 1 B 3.4.1-4 Revision No. -3&#xfd; Recirculation Loops Operating B 3.4.1 BASES ACTIONS A.1 (continued)
I ILC This Required Actior~ ~ to lo-cst pu-mp cpc recirc,-bti.on p'-mps-0(sp "A tk u,,. I. I 't ! c'* ': .I --,.foto 1&.L.. ct:- " criteri- QcCLGRG, lew fie f]It tI). ..&#xa2;k " ; vibration of the jet pi condition should be-.forward flow.-. With no recirculatior 1Q-Y9 c J associated Completi'..' brought to a MODE ,og o 7/O&#xb6;Y" status, the plant mu condition, the recirct ZoC.L)ur 4'e, eLo- 1" L of the reduced seve f( .fa 'recirculation loop co Time of 12 hours is MODE 3 from full pc challenging plant sy idoes not require tripping th~e recirculation are........ 
.......... 
...........
Fi...g 2 d Mate umps. If zero or reverse flow is detected, the alleviated by changing pump speeds to re-establish loops in operation or the Required Action and ion Time of Condition A not met, the plant must be in which the LCO does not apply. To achieve this st be brought to MODE 3 within 12 hours. In this ulation loops are not required to be operating because rity of DBAs and minimal dependence on the astdown characteristics.
The allowed Completion reasonable, based on operating experience, to reach wer conditions in an orderly manner and without stems.SURVEILLANCE SR 3.4.1.1 REQUIREMENTS This SR ensures the recirculation pump) At low core flow (i.e., < 75% of raite5oefiow),'theMCPR pfZ ._I fI5. requirements provide larger margins to the fuel cladding integrity Safety av W ,t Limit such that the potential adverse effect of early boiling transition during a LOCA is reduced. A larger__t 
... e.. laui Gorn flow. T-ho rccirculatin pumAp Spzcd m~ateh Griteria-,-
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-------_(continued)
Brunswick Unit 1 B 3.4.1-5 Revision No. e1&#xfd;"1 Recirculation Loops Operating B 3.4.1 SURVEILLANCE REQUIREMENTS c[{'-+L.._
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@G.F61at@bo Fon eirculationR pump speeds. if the diff cer e tm.1 rccircula:tion pu-mp , poadc ocoocdc tho ma2tch cri.tcria, tho wi.. .:th the-I Id,,- the ....te (I ; .. ... .... .. .. .. t is considered not in operation.
T R is not required when both loops are not in operation since are meaningless during single loop or natural circulation operation.
The Surveillance must be performed within 24 hours after both loops are in operation.
The 24 hour Frequency is consistent with the Surveillance Frequency for jet pump OPERABILITY verification and has been shown byopera experience to be adequate to detect off normal)a timely manner.REFERENCES
: 1. UFSAR, Section 5.4.1.3.2. UFSAR, Chapter 15.3. NEDC-31776P, Brunswick Steam Electric Plant Units 1 and 2 Single Loop Operation, February 1990.4. 10 CFR 50.36(c)(2)(ii).
Revision No.--3-?L/1 Brunswick Unit 1 B 3.4.1-6}}