ML102861222: Difference between revisions

From kanterella
Jump to navigation Jump to search
(Created page by program invented by StriderTol)
 
(Created page by program invented by StriderTol)
 
(3 intermediate revisions by the same user not shown)
Line 1: Line 1:
{{Adams
#REDIRECT [[GO2-10-146, License Amendment Request to Change Technical Specifications to Support an Increase in Boron Enrichment for the Standby Liquid Control System]]
| number = ML102861222
| issue date = 09/30/2010
| title = Columbia - License Amendment Request to Change Technical Specifications to Support an Increase in Boron Enrichment for the Standby Liquid Control System
| author name = Oxenford W S
| author affiliation = Energy Northwest
| addressee name =
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000397
| license number =
| contact person =
| case reference number = GO2-10-146
| document type = Letter, License-Application for Facility Operating License (Amend/Renewal) DKT 50
| page count = 20
}}
 
=Text=
{{#Wiki_filter:W. Scott Oxenford Columbia Generating Station ENERG P.O. Box 968, PE08 NORTHWEST, WA 99352-0968 Ph. 509.377.4300 1 F. 509.377.4150 soxenford
@ energy-northwest.com September 30, 2010 G02-10-146 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, D.C. 20555-0001
 
==Subject:==
COLUMBIA GENERATING STATION, DOCKET NO. 50-397 LICENSE AMENDMENT REQUEST TO CHANGE TECHNICAL SPECIFICATIONS TO SUPPORT AN INCREASE IN BORON ENRICHMENT FOR THE STANDBY LIQUID CONTROL SYSTEM
 
==Dear Sir or Madam:==
Pursuant to 10 CFR 50.90, Energy Northwest hereby requests an amendment to the Technical Specifications (TS) for Columbia Generating Station Operating License NPF-21. Energy Northwest has reviewed the proposed amendment in accordance with 10 CFR 50.92 and concludes it does not involve a significant hazards consideration.
The proposed amendment would modify TS for the Standby Liquid Control (SLC)system to reflect an increase in the boron enrichment.
The increase in boron-10 enrichment is needed to support future reloads of GE14 fuel by providing additional margin for preserving the shutdown objective of the SLC system. Reload analysis indicates that a core that is made up of a majority of GEl 4 fuel has a higher reactivity than previous Columbia core designs warranting a corresponding increase in the shutdown capability of the SLC system.The enclosure provides a description and evaluation of the proposed TS changes.Attachments to the enclosure include the following:
: 1. TS page markups 2. TS Bases page markups (for information only)3. Retyped TS pages 4. Summary of Commitments In accordance with 10 CFR 50.91, a copy of this application, with attachments, is being provided to the designated Washington State Official.Approval of the proposed amendment is requested by June 1, 2011, in order to facilitate implementation during the spring 2011 refueling outage.AUIZ(
LICENSE AMENDMENT REQUEST TO CHANGE TECHNICAL SPECIFICATIONS TO SUPPORT AN INCREASE IN BORON ENRICHMENT FOR THE STANDBY LIQUID CONTROL SYSTEM Page 2 Energy Northwest is requesting the NRC support the requested approval date, which is shorter than the preferential one year NRC review period due to the following:
: 1. The proposed reload core design anticipated that the SLC boron-1 0 enrichment would be accepted by the NRC as this change has previously been approved for use at other utilities, and is included in the standardized Technical Specifications as depicted in NUREGs 1433 and 1434. These precedents are discussed further in the Enclosure.
: 2. The requested changes proposed in this submittal had previously been included with other changes in a submittal that was not accepted by the NRC for review (see Energy Northwest submittal, dated 5/11/10, ML101390369, and NRC non-acceptance for review dated 9/13/10, ML1 02420659) based on issues unrelated to the merits of this specific proposed change.3. In order to comply with the current SLC shutdown margin requirement, the proposed cycle 21 core design would require significant changes to the GE14 fuel bundle design. This redesigned GE14 fuel may not provide the required energy to support the planned fuel cycle. Both the redesign effort and the potential impact on the fuel cycle represent a significant negative economic impact to Energy Northwest.
Should you have any questions or require additional information regarding this matter, please contact Mr. DW Gregoire, Licensing Supervisor, at (509) 377-8616.I declare under penalty of perjury that the foregoing is true and correct. Executed on the date of this letter.Respectfully, W.S. Oxe do Vice President, Nuclear Generation
& Chief Nuclear Officer
 
==Enclosure:==
 
Description and Evaluation of the Proposed TS Changes Attachments to the
 
==Enclosure:==
: 1. TS page markups 2. TS Bases page markups (for information only)3. Retyped TS pages 4. Summary of Commitments cc: NRC Region IV Administrator NRC NRR Project Manager NRC Senior Resident Inspector/988C RN Sherman -BPA/1 399 WA Horin -Winston & Strawn JO Luce -EFSEC RR Cowley -WDOH LICENSE AMENDMENT REQUEST TO CHANGE TECHNICAL SPECIFICATIONS TO SUPPORT AN INCREASE IN BORON ENRICHMENT FOR THE STANDBY LIQUID CONTROL SYSTEM Enclosure Page 1 of 9 Description and Evaluation of the Proposed TS Changes
 
==Subject:==
License Amendment Request to Change Technical Specifications (TS) in Support of an Increase in Boron-1 0 Enrichment for Standby Liquid Control (SLC) System 1.0
 
==SUMMARY==
DESCRIPTION 2.0 DETAILED DESCRIPTION 3.0 TECHNICAL EVALUATION
 
==4.0 REGULATORY EVALUATION==
 
4.1 Applicable Regulatory Requirement/Criteria 4.2 Precedent 4.3 Significant Hazards Consideration
 
===4.4 Conclusions===
5.0 ENVIRONMENTAL CONSIDERATION
 
==6.0 REFERENCES==
 
ATTACHMENTS:
: 1. TS page markups 2. TS Bases page markups (for information only)3. Retyped TS pages 4. Summary of Commitments LICENSE AMENDMENT REQUEST TO CHANGE TECHNICAL SPECIFICATIONS TO SUPPORT AN INCREASE IN BORON ENRICHMENT FOR THE STANDBY LIQUID CONTROL SYSTEM Enclosure Page 2 of 9 1.0
 
==SUMMARY==
DESCRIPTION Pursuant to 10 CFR 50.90, Energy Northwest proposes to revise the Columbia Generating Station (Columbia)
TS to increase the enrichment of Boron-1 0 in the SLC system.The proposed increase in the enrichment of the sodium pentaborate solution is required to support planned reloads of GE14 fuel. The SLC Boron-10 enrichment increase will be implemented during the spring 2011 refueling outage.2.0 DETAILED DESCRIPTION This License Amendment Request (LAR) would change TS sections 3.1.7, "Standby Liquid Control (SLC) System," and the associated TS Bases, to support a proposed increase in the SLC boron-1 0 enrichment.
New Surveillance Requirement (SR) 3.1.7.9 is added to "Verify sodium pentaborate enrichment is -- 44.0 atom percent B-10." This SR is consistent with improved Standard Technical Specifications, NUREG-1434 (Reference 2).The increase in boron-1 0 enrichment is needed to support future reloads of GEl 4 fuel by providing additional margin for preserving the shutdown objective of the SLC system.Analysis indicates that the boron-10 enrichment in the SLC solution would need to be increased to 22 atom percent. Energy Northwest is proposing a SR to ensure that all future additions of boron to the SLC tank would be at a greater than or equal to 44 atom percent B-10. The proposed increase in boron-10 enrichment provides more margin than that required by the analytical requirement to support anticipated future changes, such as the potential impact of operation in the Maximum Extended Load Line Limit Analysis (MELLLA) domain." Attachment 1 provides the marked up TS page indicating the proposed change." Attachment 2 provides the associated TS Bases page markups for information only." Attachment 3 provides the retyped TS pages." Attachment 4 provides the summary of commitments made in this submittal.
LICENSE AMENDMENT REQUEST TO CHANGE TECHNICAL SPECIFICATIONS TO SUPPORT AN INCREASE IN BORON ENRICHMENT FOR THE STANDBY LIQUID CONTROL SYSTEM Enclosure Page 3 of 9 3.0 TECHNICAL EVALUATION The SLC is designed to shut down the reactor from rated power conditions to cold shutdown in the postulated situation that some or all of the control rods cannot be inserted, i.e. anticipated transient without scram (ATWS) events. This manually operated system pumps a sodium pentaborate solution into the vessel to provide neutron absorption and achieve a sub-critical reactor condition.
The SLC system is designed to inject over a wide range of reactor operating pressures.
SLC shutdown capability (in terms of the required reactor boron concentration) is evaluated for each fuel reload and is reported in the cycle-specific Supplemental Reload Licensing Report (SRLR). Reload core design analyses are performed on a cycle specific basis to ensure that required reactivity margins are maintained.
Columbia's current fuel vendor, Global Nuclear Fuels (GNF), performed analysis using the approved methods described in NEDE-2401 1-P-A (Reference
: 3) and determined that reloads of GE14 fuel for the Columbia core would require the average concentration of natural boron delivered to the reactor core by the SLC system to be raised from 660 parts per million (ppm) to 780 ppm. The proposed increase in enrichment of boron-10 provides the required concentration of boron to assure sufficient shutdown margin is maintained in the reactor so that the SLC design function of bringing the reactor to a subcritical condition is achieved.Natural boron contains 19.8 atom percent of the boron-10 isotope. Boron-10, with its large neutron absorption capability, is the active component in sodium pentaborate.
In order to achieve the increased neutron absorber concentration equivalent to 780 ppm natural boron, Energy Northwest intends to use sodium pentaborate solution enriched with the boron-1 0 isotope, which is chemically and physically similar to the current solution.
The use of sodium pentaborate enriched with the boron-10 isotope provides a faster negative reactivity insertion rate than the same quantity of sodium pentaborate with natural boron. A sodium pentaborate solution enrichment of 22 atom percent boron-10 has been calculated to achieve an equivalent concentration of 780 ppm natural boron in the reactor.With this LAR, Energy Northwest is proposing to conservatively double the analytically determined atom percent boron-1 0 requirements in order to support planned future improvements at the site. Increasing the enrichment to the expected value anticipated for future improvements, such as operation in the MELLLA domain, will allow Energy Northwest to change out the requisite SLC tank contents this one time, and will provide extra conservatism until such a time as future improvements are approved and implemented.
Accordingly, a new TS SR 3.1.7.9 is added to verify that sodium pentaborate enrichment is > 44 atom percent boron-10 prior to addition to the SLC tank. This change does not have any impact on SLC operation or the ability of the system to perform its shutdown function.
Operation within the Acceptable Operation region of TS Figure 3.1.7-1, with a sodium pentaborate enrichment of -- 44 atom percent boron-10 in LICENSE AMENDMENT REQUEST TO CHANGE TECHNICAL SPECIFICATIONS TO SUPPORT AN INCREASE IN BORON ENRICHMENT FOR THE STANDBY LIQUID CONTROL SYSTEM Enclosure Page 4 of 9 accordance with SR 3.1.7.9, will exceed the delivery requirement equivalent to 780 ppm natural boron in the reactor core.There are no significant impacts of the new sodium pentaborate solution on the mechanical and electrical aspects of the SLC system. The SLC pump, motor, and system valves are capable of delivering the required minimum flow rate to the reactor vessel under worst case postulated operating conditions.
The proposed change to use sodium pentaborate solution enriched with the boron-1 0 isotope does not affect the SLC system flow rate.Current TS SR 3.1.7.2 and SR 3.1.7.4 require verification that the temperature and concentration of the SLC system sodium pentaborate solution is maintained within the solubility limits specified in TS figure 3.1.7-1. Since the atomic weights of naturally occurring boron and that enriched in the boron-1 0 isotope differ only slightly (less than one percent), there will be no significant impact on the solubility limit of enriching the sodium pentaborate solution with the boron-10 isotope. In addition, the maximum solution concentration is not changing.
Thus, the concentration and temperature requirements to maintain the boron in solution remains unchanged.
The volume stored in the SLC tank is unchanged, and hence, pH control of the suppression pool during a Loss of Coolant Accident (LOCA) event remains unaffected by this proposed change in boron-10 enrichment.
The existing SLC system design requires injection of a quantity of boron that includes an additional 25 percent above that needed for an in-vessel boron concentration of 660 ppm, to allow for imperfect mixing and leakage. As part of this proposed change, an additional 25 percent above that needed for an in-vessel boron concentration equivalent to 780 ppm natural boron will also be injected.
This change is consistent with the Bases for TS 3.1.7 contained in NUREG-1434 (Reference 2). The NRC has previously approved a similar change regarding the increase in boron enrichment to support the use of GE14 fuel for Brunswick (Reference
: 1) and Nine Mile Point Unit No. 2 (Reference 4).Increasing the boron-1 0 enrichment levels will continue to ensure that the SLC system satisfies the ATWS, 10 CFR 50.62, requirements for future proposed core reloads.
 
==4.0 REGULATORY EVALUATION==
 
4.1 Applicable Regulatory Requirements
/ Criteria The SLC system was designed and licensed to the following reactivity control related General Design Criteria: Criterion 26 -"Reactivity control system redundancy and capability." Two independent reactivity control systems of different design principles shall be provided .... The second reactivity control system shall be capable of reliably controlling the rate of reactivity changes resulting fromnplanned, normal power LICENSE AMENDMENT REQUEST TO CHANGE TECHNICAL SPECIFICATIONS TO SUPPORT AN INCREASE IN BORON ENRICHMENT FOR THE STANDBY LIQUID CONTROL SYSTEM Enclosure Page 5 of 9 changes (including xenon burnout) to assure acceptable fuel design limits are not exceeded.
One of the systems shall be capable of holding the reactor core subcritical under cold conditions.
Criterion 27 -"Combined reactivity control systems capability." The reactivity control system shall be designed to have a combined capability, in conjunction with poison addition by the emergency core cooling system, of reliably controlling reactivity change to assure that under postulated accident conditions and with appropriate margin for stuck rods, the capability to cool the core is maintained.
Other applicable Regulations:
In 10 CFR 50.36(c)(3), the NRC states, "Surveillance requirements are requirements relating to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation would be within safety limits, and that the limiting conditions for operation would be met." The SLC system also satisfies the 10 CFR 50.62 requirements for ATWS events.10 CFR 50.62(c)(4) states: Each boiling water reactor must have a standby liquid control system (SLCS) with the capability of injecting into the reactor pressure vessel a borated water solution at such a flow rate, level of boron concentration and boron-1 0 isotope enrichment, and accounting for reactor pressure vessel volume, that the resulting reactivity control is at least equivalent to that resulting from injection of 86 gallons per minute of 13 weight percent sodium pentaborate decahydrate solution at the natural boron-1 0 isotope abundance into a 251-inch inside diameter reactor pressure vessel for a given core design. The SLCS and its injection location must be designed to perform its function in a reliable manner...Alternative Source Term analyses credit the use of the SLC system for maintaining pH of the suppression pool following a LOCA to satisfy, in part, the requirements of 10 CFR 50.67. Regulatory Guide 1.183 delineates that credit for iodine deposition in the suppression pool is allowed as long as suppression pool pH is maintained above 7.Energy Northwest has evaluated the proposed changes against the applicable regulatory requirements and acceptance criteria and finds the proposed increase in the boron-1 0 enrichment of the SLC system continues to meet all regulatory requirements.
The proposed TS amendment:
LICENSE AMENDMENT REQUEST TO CHANGE TECHNICAL SPECIFICATIONS TO SUPPORT AN INCREASE IN BORON ENRICHMENT FOR THE STANDBY LIQUID CONTROL SYSTEM Enclosure Page 6 of 9 1. Does not alter the design or function of any reactivity control system;2. Does not result in any change in the qualifications of any component; and 3. Does not result in the reclassification of any component's status in the areas of shared, safety related, independent, redundant, and physical or electrical separation.
 
===4.2 Precedents===
The NRC approved an increase in boron-1 0 enrichment for Brunswick (Reference 1)corresponding to an increase from 660 ppm to 720 ppm natural boron equivalent to support a transition to GE14 fuel. Columbia is proposing a similar approach involving an increase from 660 ppm to a slightly higher value of 780 ppm, also related to a future use of GE14 fuel. The NRC approved an increase in boron-10 enrichment for Nine Mile Point Unit No. 2 (NMP2)[Reference 4] which entailed an increase from 660 ppm to 780 ppm to support a transition to GE14 fuel, which is the same net increase in delivery of natural boron equivalent, proposed for Columbia with this LAR. Brunswick and NMP2, as well as the proposed Columbia operation, involve operations with a fuel design with a higher reactivity (GE14) than the previous fuel designs in use at the respective plants (GEl 1 for Brunswick and NMP2, Atrium-10 for Columbia).
4.3 Significant Hazards Consideration Energy Northwest has evaluated whether or not a significant hazards consideration is involved with the proposed change, by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below: 4.3.1 Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?
Response:
No.The SLC system is designed to provide sufficient negative reactivity to bring the reactor from full power to a subcritical condition at any time in a fuel cycle, without taking credit for control rod movement.
The proposed changes to the SLC sodium pentaborate solution requirements maintain the capability of the SLC to perform this reactivity control function, and assure continued compliance with the requirements of 10 CFR 50.62 for ATWS. The proposed changes do not impact the LOCA suppression pool pH control function of SLC because single-pump minimum flow and sodium pentaborate solution concentration (weight percent) are not changed from the level credited in the LOCA analysis.
The SLC is provided to mitigate ATWS events and LOCA and, as such, is not considered to be an initiator of the ATWS event, LOCA, or any other analyzed accident.
The use of sodium pentaborate solution enriched with LICENSE AMENDMENT REQUEST TO CHANGE TECHNICAL SPECIFICATIONS TO SUPPORT AN INCREASE IN BORON ENRICHMENT FOR THE STANDBY LIQUID CONTROL SYSTEM Enclosure Page 7 of 9 the boron-10 isotope, which is chemically and physically similar to the current solution, does not alter the design or operation of the SLC or increase the likelihood of a system malfunction that could increase the consequences of an accident.Based on the above discussion, it is concluded that the proposed changes do not involve a significant increase in the probability or consequences of an accident previously evaluated.
4.3.2 Does the proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?
Response:
No.Injection of sodium pentaborate solution into the reactor vessel has been considered in the plant design. The proposed changes revise the SLC boron solution requirements such that the capability of the SLC system to bring the reactor to a subcritical condition without taking credit for control rod movement is maintained, considering operation with an equilibrium core of GE14 fuel. The use of sodium pentaborate solution enriched with the boron-1 0 isotope, which is chemically and physically similar to the current solution, does not alter the design, function, or operation of the SLC system. The correct boron-10 enrichment is assured by the proposed addition of an SR to the TS. The solution concentration and volume are not changed; thus, the existing minimum volume and solution and piping temperature specified in the TS will ensure that the boron remains in solution and does not precipitate out in the SLC storage tank or in the SLC pump suction piping. The minimum volume and concentration specified in the TS ensure that the LOCA suppression pool pH control function is not impacted.Therefore, the proposed changes do not create the possibility of a new or different kind of accident from any accident previously evaluated.
4.3.3 Does the proposed change involve a significant reduction in a margin of safety?Response:
No.The proposed changes revise the SLC boron solution requirements to maintain the capability of the SLC system to bring the reactor to a subcritical condition without taking credit for control rod movement.
These changes support operation with an equilibrium core of GE14 fuel and assure continued compliance with the requirements of 10 CFR 50.62. The minimum required average boron-1 0 concentration in the reactor core, resulting from the injection of sodium pentaborate solution by the SLC LICENSE AMENDMENT REQUEST TO CHANGE TECHNICAL SPECIFICATIONS TO SUPPORT AN INCREASE IN BORON ENRICHMENT FOR THE STANDBY LIQUID CONTROL SYSTEM Enclosure Page 8 of 9 system, has been determined using approved analytical methods. The analysis demonstrates that sufficient shutdown margin is maintained in the reactor such that the reactivity control function of the SLC system is assured. The additional quantity of boron included to account for imperfect mixing and leakage is maintained at 25 percent. No change in the solution pH or volume is made. Thus, the safety margin is maintained to bring the reactor subcritical in the event of an ATWS and to control suppression pool pH in the event of a LOCA.Therefore, the proposed changes do not involve a significant reduction in a margin of safety.4.4 Conclusions Based on the considerations discussed above, (1) there is a reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.5.0 ENVIRONMENTAL CONSIDERATION A review has determined that the proposed changes would change a requirement with respect to the 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 changes do not involve: (i) a significant hazards consideration; (ii) a significant change in the types or significant increase in the amounts of any effluents that may be released offsite; or (iii) a significant increase in individual or cumulative occupational radiation exposure.
Accordingly, the proposed changes meet the eligibility criterion for categorical exclusion set for in 10 CFR 51.22(c)(9).
Therefore, pursuant to 10 CFR 51.22(b), an environmental assessment of the proposed change is not required.
 
==6.0 REFERENCES==
: 1. NRC letter to the Carolina Power and Light Company, "Brunswick Steam Electric Plant, Units 1 and 2 -Issuance of Amendments Re: Standby Liquid Control Sodium Pentaborate Solution Concentration and Requirements (TAC Nos.MB5680 AND MB5681)," dated March 25, 2003.2. NUREG-1434, Rev. 3, "Standard Technical Specifications General Electric Plants, BWR/6," dated March 2004.
LICENSE AMENDMENT REQUEST TO CHANGE TECHNICAL SPECIFICATIONS TO SUPPORT AN INCREASE IN BORON ENRICHMENT FOR THE STANDBY LIQUID CONTROL SYSTEM Enclosure Page 9 of 9 3. NEDE-2401 1-P-A and NEDE-2401 1-P-A-US, Revision 16, "General Electric Standard Application for Reactor Fuel (GESTAR II) and Supplement for the United States," dated October 2007.4. NRC to Nine Mile Point Nuclear Station, LLC, "Nine Mile Point Nuclear Station No.2 -Issuance of Amendment RE: Boron Concentration in the Standby Liquid Control System (TAC No. MC0595)," dated February 13, 2004 (ADAMS Accession No. ML040350553).
LICENSE AMENDMENT REQUEST TO CHANGE TECHNICAL SPECIFICATIONS TO SUPPORT AN INCREASE IN BORON ENRICHMENT FOR THE STANDBY LIQUID CONTROL SYSTEM Attachment 1 TS page markups 3.1.7-3 SLC System 3.1.7 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.1.7.5 Verify each SLC subsystem manual and power 31 days operated valve in the flow path that is not locked, sealed, or otherwise secured in position, is in the correct position or can be aligned to the correct position.SR 3.1.7.6 Verify each pump develops a flow rate In accordance
* 41.2 gpm at a discharge pressure with the> 1220 psig. Inservice Testing Program SR 3.1.7.7 Verify flow through one SLC subsystem from 24 months on a pump into reactor pressure vessel. STAGGERED TEST BASIS SR 3.1.7.8 Verify all heat traced piping between 24 months storage tank and pump suction valve is unblocked.
AND Once within 24 hours after solution temperature is.restored within the limits of Figure 3.1.7-1 SR 3.1.7.9 Verify sodium pentaborate enrichment is> 44.0 atom percent B-I10.I I Prior to addition to SLC Tank Columbia Generating Station 3.1.7-3 Amendment No. 149,169 199 LICENSE AMENDMENT REQUEST TO CHANGE TECHNICAL SPECIFICATIONS TO SUPPORT AN INCREASE IN BORON ENRICHMENT FOR THE STANDBY LIQUID CONTROL SYSTEM Attachment 2 TS Bases page markups (for information only)B 3.1.7-1 B 3.1.7-2 B 3.1.7-7 SLC System B 3.1.7 B 3.1 REACTIVITY CONTROL SYSTEMS B 3.1.7 Standby Liquid Control (SLC) System BASES BACKGROUND The SLC System is designed to provide the capability of bringing the reactor, at any time in a fuel cycle, from full power and minimum control rod inventory (which is at the peak of the xenon transient) to a subcritical condition with thereactor in the most reactive xenon free state without taking credit for control rod movement.
The SLC System satisfies the requirements of 10 CFR 50.62 (Ref. 1) on anticipated transient without scram (ATWS).The SLC System is also used to maintain suppression pool pH at or above 7 following a loss of coolant accident (LOCA)involving significant fission product releases.
Maintaining suppression pool pH levels at or above 7 following an accident ensures that iodine will be retained in the suppression pool water (Ref. 4).The SLC System consists of a boron solution storage tank, two positive displacement pumps, two explosive valves, which are provided in parallel for redundancy, and associated piping and valves used to transfer borated water from the storage tank to the reactor pressure vessel (RPV). The borated solution is discharged through the high pressure core spray system sparger.APPLICABLE The SLC System is manually initiated from the main control SAFETY ANALYSES room, as directed by the emergency operating procedures, if the operator believes the reactor cannot be shut down, or kept shut down, with the control rods. The SLC System is used in the event that not enough control rods can be'inserted to accomplish.shutdown and cooldown in the normal manner. The SLC System injects borated water into the reactor core to compensate for all of the various reactivity effects that could occur during plant operation.
To meet equivalentin this objective, it is necessary to inject, using both SLC Boron-10 to a ' pumps, a quantity of boron that prcduees a ..ne...trati.
n ..f'cnna o-6 ppm of natural boron in the reactor core, including concentration of recirculation loops, at 70°F and normal reactor water level.780 (continued)
Columbia Generating Station B 3.1.7-1 Revision 49 SLC System B 3.1.7 BASES APPLICABLE SAFETY ANALYSES (continued)
The volume limit in SR 3.1.7.1 and the temperature versus concentration limits in Figure 3.1.7-1 are calculated such that To allow for potential leakage and imperfect mixing in the reactor system, an additional amount of boron equal to 25%of the amount cited above is added (Ref. 2). An additional
')- ý^wi, 4 A ^- A 4-^ A,,A 4- ^. ,44 1 it+-4,. 4.- 4-; -, flflk I I-..the residual heat romolval shutdewn eeeling pipng. 44etur, versus e .U, , .H.9. 6 .7 i the required concentration is achieved accounting for dilution in the RPV with normal water level and including the water volume in the residual heat removal shutdown cooling piping and in the recirculation loop piping.aehi-e-d.
This quantity'of borated solution is the amount that is above the pump suction shutoff level in the boron solution storage tank. No credit is taken for the portion of the tank volume that cannot be injected.Following a LOCA, of fsite doses. from the accident will remain within 10 CFR 50.67, "Accident Source Term," limits (Ref. 5) provided sufficient iodine activity is retained in the suppression pool. Credit. for iodine deposition in the suppression pool is allowed (Ref. 4) as long as suppression pool pH is maintained at or above 7. Alternative Source Term analyses credit the use of the SLC System for maintaining the pH of the suppression pool at or above 7.The SLC System satisfies Criteria 3 and 4 of Reference 3.The OPERABILITY of the SLC System provides backup capability for reactivity control,.independent of normal reactivity control provisions provided by the control rods.Additionally, an OPERABLE SLC System has the ability to inject boron under post LOCA conditions to maintain the suppression pool pH above 7. The OPERABILITY of the SLC System is based on the conditions of the borated solution in the storage tank and the availability of a flow path to the RPV, including the OPERABILITY of the pumps and valves.Two SLC subsystems are required to be OPERABLE, each containing an OPERABLE pump, an explosive valve and associated piping, valves, and instruments and controls to ensure an OPERABLE flow path.APPLICABILITY In MODES 1 and 2, shutdown capability is required.
In MODES 3 and 4, control rods are not able to be withdrawn since the reactor mode switch is in shutdown and a control rod block is applied. This provides adequate controls to ensure the reactor remains subcritical.
In MODE 5, only a (continued)
Columbia Generating Station B 3.1.7-2 Revision 49 SLC System B 3.1.7 BASES SURVEILLANCE REQUIREMENTS SR 3.1.7.7 and SR 3.1.7.8 (continued) acceptable method for verifying that the suction piping up to the suction valve is unblocked is to pump from the storage tank to the test tank. Upon completion of this verification, the pump suction piping must be drained and flushed with demineralized water since the suction piping between the pump suction valve and pump suction is not heat traced. The 24 month Frequency is acceptable since there is a low probability that the subject piping will be blocked due to precipitation of the boron from solution in the heat traced piping. However, if, in performing SR 3.1.7.1, it is determined that the temperature of the solution in the storage tank has fallen below the specified minimum, SR 3.1.7.8 must be performed once within 24 hours after the solution temperature is restored within the limits of Figure 3.1.7-1.REFERENCES 10 CFR 50.62.2. FSAR, Section 9.3.5.3.3. 10 CFR 50.36(c)(2)(ii).
: 4. Regulatory Guide 1.183, July 2000, 5. 10 CFR 50.67, "Accident Source Term." SR 3.1.7.9 Enriched sodium pentaborate solution is made by mixing granular, enriched sodium pentaborate with water. Isotopic tests on the granular sodium pentaborate to verify the actual B-10 enrichment must be performed prior to addition to the SLC tank in order to ensure that the proper B-10 atom percentage is being used.Columbia Generating Station B 3.-1;7-7 Revision 49 LICENSE AMENDMENT REQUEST TO CHANGE TECHNICAL SPECIFICATIONS TO SUPPORT AN INCREASE IN BORON ENRICHMENT FOR THE STANDBY LIQUID CONTROL SYSTEM Attachment 3 Retyped TS pages 3.1.7-3 SLC System 3.1.7 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.1.7.5 Verify each SLC subsystem manual and power 31 days operated valve in the flow path that is not locked, sealed, or otherwise secured in position, is in the correct position or can be aligned to the correct position.SR 3.1.7.6 Verify each pump develops a flow rate In accordance
> 41.2 gpm at a discharge pressure with the> 1220 psig. Inservice Testing Program SR 3.1.7.7 Verify flow through one SLC subsystem from 24 months on a pump into reactor pressure vessel. STAGGERED TEST BASIS SR 3.1.7.8 Verify all heat traced piping between 24 months storage tank and pump suction valve is unblocked.
AND Once within 24 hours after solution temperature is restored within the limits of Figure 3.1.7-1 SR 3.1.7.9 Verify sodium pentaborate enrichment is Prior to> 44.0 atom percent B-IO. addition to SLC Tank Columbia Generating Station 3.1.7-3 Amendment No. 149,169,194 LICENSE AMENDMENT REQUEST TO CHANGE TECHNICAL SPECIFICATIONS-TO SUPPORT AN INCREASE IN BORON ENRICHMENT FOR THE STANDBY LIQUID CONTROL SYSTEM Attachment 4 Summary of Commitments The following table identifies the regulatory commitments in this document.
Any other statements in this submittal intended or planned actions, are provided for information purposes, and are not considered to be regulatory commitments.
TYPE SCHEDULED COMMITMENT one-time continuing COMPLETION DATE compliance Raise the Standby Liquid Control Prior to startup from tank boron enrichment level to be X refuel outage 20 in compliance with revised analysis (currently planned for requirements.
spring 2011).}}

Latest revision as of 04:31, 13 April 2019

Redirect to:

Retrieved from "https://kanterella.com/w/index.php?title=ML102861222&oldid=1458703"