ML072220103
ML072220103 | |
Person / Time | |
---|---|
Site: | Palisades ![]() |
Issue date: | 07/25/2007 |
From: | Nuclear Management Co |
To: | Document Control Desk, Office of Nuclear Reactor Regulation |
References | |
Download: ML072220103 (34) | |
Text
I- PASSPORT DOCUMENT 11 To HOOD DS US NRC Facility PL Department : TRANSMITTAL Address From Address C-DOC CNTRL-PL Attention:
27780 BLUE STAR MEMORIAL HWY fllll~iII Page lllH1 llill City COVERT State: MI Postal Code: 49043 Country UNITED STATES Email Contact Date/Time 07/25/2007 1:1:34 Transmittal Group Id: 0000005312 Trans No. 000043453
Title:
SEE ATTACHED INSTRUCTIONS Total Items: 00001 Item Facility Type Sub Document Number Sheet Doc Status Revision Doc Date Copy # Media Cpys 0001 PL LIC TECH TECH SPECS ACTIVE 225 A 12 HC 01 Marked (*) documents require your acknowledgement.
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TECHNICAL SPECIFICATIONS PALISADES PLANT Docket 50-255 - License DPR-20 Page Change Instructions Technical Specifications Bases Changes July 31. 2007 Revise your copy of the Palisades Technical Specification Bases by removing the pages identified below and inserting the attachedrevised and additionalpages. The revised and additional pages are identified by a revision date at the bottom of the pages and contain vertical lines in the margin indicating the areas of change.
TECHNICAL SPECIFICATIONS BASES REMOVE INSERT List of Effective Pages (2 pgs), Rev 07/18/07 List of Effective Pages (2 pgs), Rev 07/31/07 Section B 3.4.6'(6 pgs), Rev 09/21/06 Section B 3.4.6 (6 pgs), Rev 07/31/07 Section B 3.4.7 (7 pgs), Rev 09/21/06 Section B 3.4.7 (7 pgs), Rev 07/31/07 Section B 3.4.8 (5 pgs), Rev 05/01/06 Section B 3.4.8 (5 pgs), Rev 07/31/07 Section B 3.7.6 (4 pgs), Rev 12/15/05 Section B 3.7.6 (4 pgs), Rev 07/31/07 Section B 3.9.4 (4 pgs), Rev 05/01/06 Section B 3.9.4 (4 pgs), Rev 07/31/07 Section B 3.9.5 (4 pgs), Rev 05/01/06 Section B 3.9.5 (4 pgs), Rev 07/31/07
PALISADES TECHNICAL SPECIFICATIONS BASES 1 LIST OF EFFECTIVE PAGES COVERSHEET Title Page 223 - Revised 09/21/06 TABLE OF CONTENTS Page i 223 Page ii 221 TECHNICAL SPECIFICATIONS BASES Bases 2.0 Pages B2.1.1-1 -B2.1.1-4 Revised 09/28/01 Pages B 2.1.2 B 2.1.2-4 189 Bases 3.0 Pages B 3.0 B 3.0-15 Revised 02/24/05 Bases 3.1 Pages B 3.1.1 B 3.1.1-5 189 Pages B 3.1.2 B 3.1.2-6 Revised 09/09/03 Pages B 3.1.3 B 3.1.3-4 189 Pages B 3.1.4 23.1.4-13 Revised 07/18/07 Pages B 3.1.5 B 3.1.5-7 Revised 07/02/04 Pages B 3.1.6 B 3.1.6-9 Revised 07/30/03 Pages B 3.1.7 B 3.1.7-6 Revised 05/15/07 Bases 3.2 Pages B 3.2.1-1 - B 3.2.1-11 Revised 08/06/04 Pages B 3.2.2-1 - B 3.2.2-3 Revised 09/28/01 Pages B 3.2.3-1 - B 3.2.3-3 Revised 09/28/01 Pages B 3.2.4-1 - B 3.2.4-3 189 - Revised 08/09/00 Bases 3.3 Pages B 3.3.1 B 3.3.1-35 Revised 02/24/05 Pages B 3.3.2 B 3.3.2-10 189 - Revised 02/12/01 Pages B 3.3.3 B 3.3.3-24 Revised 02/14/07 Pages B 3.3.4 B 3.3.4-12 Revised 09/09/03 Pages B 3.3.5 B 3.3.5-6 Revised 01/26/04 Pages B 3.3.6 B 3.3.6-6 189 - Revised 02/12/01 Pages B 3.3.7 B 3.3.7-12 Revised 04/19/05 Pages B 3.3.8 B 3.3.8-6 Revised 02/24/05 Pages B 3.3.9 B 3.3.9-5 189 - Revised 08/09/00 Pages B 3.3.10-1 - B 3.3.10-4 189 Bases 3.4 Pages B 3.4.1-1 - B 3.4.1-4 Revised 08/24/04 Pages B 3.4.2-1 - B 3.4.2-2 189 Pages B 3.4.3-1 - B 3.4.3-7 Revised 01/27/05 Pages B 3.4.4-1 - B 3.4.4-4 Revised 09/21/06 Pages B 3.4.5-1 - B 3.4.5-5 Revised 09/21/06 Pages B 3.4.6-1 - B 3.4.6-6 Revised 07/31/07 Pages B 3.4.7-1 - B 3.4.7-7 Revised 07/31/07 Pages B 3.4.8-1 - B 3.4.8-5 Revised 07/31/07 Pages B 3.4.9 B 3.4.9-6 189 Pages B 3.4.10-1 - B 3.4.10-4 189 Pages B 3.4.11-1 - B 3.4.11-7 Revised 02/24/05 Pages B 3.4.12-1 - B.3.4.12-13 Revised 02/24/05 Pages B 3.4.13-1 - B 3.4.13-7 Revised 09/21/06 Pages B 3.4.14-1 - B 3.4.14-8 189 - Revised 08/09/00 Pages B 3.4.15-1 - B 3.4.15-6 Revised 02/24/05 Pages B 3.4.16-1 - B 3.4.16-5 Revised 02/24/05 Pages B3.4.17-1 - B 3.4.17-7 223 Revised 07/31/2007
PALISADES TECHNICAL SPECIFICATIONS BASES 2 LIST OF EFFECTIVE PAGES Bases 3.5 Pages B 3.5.1 B 3.5.1-5 189 Page B.3.5.1-6 191 Page B 3.5.1-7 189 Page B 3.5.1-8 191 Pages B 3.5.2 B 3.5.2-12 Revised 04/22/2002 Pages B 3.5.3 B 3.5.3-4 Revised 07/22/02 Pages B 3.5.4 B 3.5.4-7 Revised 04/22/2002 Pages B 3.5.5 B 3.5.5-5 189 Bases 3.6 Pages B 3.6.1-1 - B 3.6.1-4 Revised 12/10/02 Pages B 3.6.2-1 - B 3.6.2-8 Revised 08/12/03 Pages B 3.6.3-1 - B 3.6.3-12 Revised 03/02/04 Pages B 3.6.4-1 - B 3.6.4-3 Revised 04/27/01 Pages B 3.6.5-1 - B 3.6.5-3 Revised 09/09/03 Pages B 3.6.6-1 - B 3.6.6-12 Revised 05/03/06 Bases 3.7 Pages B 3.7.1-1 - B 3.7.1-4 Revised 08/06/04 Pages B 3.7.2-1 - B 3.7.2-6. Revised 12/02/02 Pages B 3.7.3-1 - B 3.7.3-5 Revised 12/02/02 Pages B 3.7.4-1 B 3.7.4-4 Revised 02/24/05 Pages B 3.7.5 B 3.7.5-9 Revised 02/24/05 Pages B 3.7.6 B 3.7.6-4 Revised 07/31/07 Pages B 3.7.7 B 3.7.7-9 Revised 06/07/05 Pages B 3.7.8 B 3.7.8-8 Revised 08/01/01 Pages B 3.7.9 B 3.7.9-3 Revised 07/16/01 Pages B 3.7.10-1 - B 3.7.10-7 Revised 08/01/01 Pages Pages Pages B 3.7.11-1 B 3.7.12-1 B 3.7.13-1
- B 3.7.11-5
- B3.7.12-7
- B 3.7.13-3 189 Revised 07/16/03 189 - Revised 08/09/00 0
Pages B 3.7.14-1 - B 3.7.14-3 Revised 09/09/03 Pages B 3.7.15-1 - B 3.7.15-2 207 Pages B 3.7.16-1 - B 3.7.16-3 207 Pages B 3.7.17-1 - B 3.7.17-3 Revised 07/22/02 Bases 3.8 Pages B 3.8.1 B 3.8.1-24 Revised 02/24/05 Pages B 3.8.2 B 3.8.2-4 Revised 11/06/01 Pages B 3.8.3 B 3.8.3-7 Revised 07/22/02 Pages B 3.8.4 B 3.8.4-9 Revised 07/13/06 Pages B 3.8.5-1 -B3.8.5-3 Revised 11/06/01 Pages B 3.8.6 B 3.8.6-6 189 - Revised 08/09/00 Pages B 3.8.7 B 3.8.7-3 189 Pages B3.8.8 B 3.8.8-3 Revised 11/06/01 Pages B 3.8.9 B 3.8.9-7 Revised 11/06/01 Pages B 3.8.10 B 3.8.10-3 Revised 11/06/01 Bases 3.9 Pages B 3.9.1 B 3.9.1-4 189 - Revised 08/09/00 Pages B 3.9.2 B 3.9.2-3 189 - Revised 02/12/01 Pages B 3.9.3 B 3.9.3-6 189 - Revised 08/09/00 Pages B 3.9.4 B 3.9.4-4 Revised 07/31/07 Pages B 3.9.5 B 3.9.5-4 Revised 07/31/07 Pages B 3.9.6 B 3.9.6-3 189 - Revised 02/27/01 Revised 07/31/2007
PCS Loops - MODE 4 B 3.4.6 B 3.4 PRIMARY COOLANT SYSTEM (PCS)
B 3.4.6 PCS Loops - MODE 4 BASES BACKGROUND In MODE 4, the primary function of the primary coolant is the removal of decay heat and transfer of this heat to the Steam Generators (SGs) or Shutdown Cooling (SDC) heat exchangers. The secondary function of the primary coolant is to act as a carrier for soluble neutron poison, boric acid.
In MODE 4, either Primary Coolant Pumps (PCPs) or SDC trains can be used for coolant circulation. The intent of this LCOis to provide forced flow from any one (of the four) PCP or one SDC train for decay heat removal and transport. The flow providedby one PCP loop or SDC train is adequate for heat removal. The other intent of this LCO is to require that two paths be available to provide redundancy for heat removal.
APPLICABLE The boron concentration must be uniform throughout the PCS volume SAFETY ANALYSES to prevent stratification of primary coolant at lower boron concentrations which could result in a reactivity insertion. Sufficient mixing of the primary coolant is assured if one PCP is in operation. PCS circulation is considered in the determination of the time available for mitigation of the inadvertent boron dilution event. By imposing a minimum flow through the reactor core of 2810 gpm, sufficient time is provided for the operator to terminate a boron dilution under asymmetric flow conditions. Due to its system configuration (i.e.,, no throttle valves) and large volumetric flow rate, a minimum flow rate is not imposed on the PCPs.
PCS Loops - MODE 4 satisfies Criterion 4 of 10 CFR 50.36(c)(2).
LCO The purpose of this LCO is to require that two loops or trains, PCS or SDC, be OPERABLE in MODE 4 and one of these loops or trains to be in operation. The LCO allows the two loops that are required to be OPERABLE to consist of any combination of PCS and SDC System loops. Any one PCS loop in operation, or SDC in operation with a flow 2810 gpm through the reactor core, provides enough flow to remove the decay heat from the core with forced circulation and provide sufficient mixing of the soluble boric acid. An additional loop or train is required to be OPERABLE to provide redundancy for heat removal.
Palisades Nuclear Plant B 3.4.6-1 Revised 07/31/2007
PCS Loops - MODE 4 B 3.4.6 BASES LCO A SDC train may be considered OPERABLE (but not necessarily in (continued) operation) during, re-alignment to, and when it is re-aligned for, LPSI service or for testing, if it is capable of being (locally or remotely) realigned to the SDC mode of operation and is not otherwise inoperable. Since SDC is a manually initiated system, it need not be considered inoperable solely because some additional manual valve realignments must be made in addition to the normal initiation actions. Because of the dual functions of the components that comprise the LPSI and shutdown cooling systems, the LPSI alignment may be preferred.
Note 1 permits all PCPs and SDC pumps to not be in operation < 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> per 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> period. The Note prohibits boron dilution when forced flow is stopped because an even concentration distribution cannot be ensured. Core outlet temperature is to be maintained at least 10°F below saturation temperature so that no vapor bubble may form and possibly cause a natural circulation flow obstruction. The response of the PCS without the PCPs or SDC pumps depends on the core decay heat load and the length of time that the pumps are stopped. As decay heat diminishes, the effects on PCS temperature and pressure diminish. Without cooling by forced flow, higher heat loads will cause the primary coolant temperature and pressure to increase at a rate proportional to the decay heat load. Because pressure can increase, the applicable system pressure limits.(Pressure and Temperature (P/T) limits or Low Temperature Overpressure Protection (LTOP) limits) must be observed and forced SDC flow or heat removal via the SGs must be re-established prior to reaching the pressure limit. The circumstances for stopping both PCPs or SDC pumps are to be limited to situations where:
- a. Pressure and temperature increases can be maintained well within the allowable pressure (P/T limits and LTOP) and 10°F subcooling limits; or
- b. An alternate heat removal path through the SGs is in operation.
In MODE 4, it is sometimes necessary to stop all PCPs or SDC forced circulation. This is permitted to change operation from one SDC train to the other, perform surveillance or startup testing, perform the transition to and from SDC, or to avoid operation below the PCP minimum net positive suction head limit. The time period is acceptable because natural circulation is acceptable for decay heat removal, the primary coolant temperature can be maintained subcooled, and boron stratification affecting reactivity control is not expected.
Palisades Nuclear Plant B 3.4.6-2 Revised 07/31/2007
PCS Loops - MODE 4 B 3.4.6 BASES LCO Note 2 requires that one of the following conditions be satisfied before (continued) forced circulation (starting the first PCP) may be started:
- a. SG secondary temperature is _<T,;
- b. SG secondary temperature is < 1 00°F above To, and shutdown cooling is isolated from the PCS, and PCS heatup/cooldown rate is < 10°F/hour; or
- c. SG secondary temperature is < 100OF above To, and shutdown cooling is isolated from the PCS, and pressurizer level is < 57%.
Satisfying any of the above conditions will preclude a large pressure surge in the PCS when the PCP is started. Energy additions from the steam generators could occur if a PCP was started when the steam generator secondary temperature is significantly above the PCS temperature. The maximum pressurizer level at which credit is taken for having a bubble (57%, which provides about 700 cubic feet of steam space) is based on engineering judgement and verified by LTOP analysis.
This level provides the same steam volume to dampen pressure transients as would be available at full power.
Note 3 specifies a limitation on the simultaneous operation of primary coolant pumps P-50A and P-50B which allows the pressure limits in LCO 3.4.3, "PCS Pressure and Temperature Limits," and LCO 3.4.12, "Low Temperature Overpressure Protection System," to be higher than they would be without this limit. This is bedause the pressure in the reactor vessel downcomer region when primary coolant pumps P-50A and P-50B are operated simultaneously is higher than the pressure for other two primary coolant pump combinations.
An OPERABLE PCS loop consists of any one (of the four) OPERABLE PCP and an SG that has the minimum water level specified in SR 3.4.6.2 and is OPERABLE. PCPs are OPERABLE if they are capable of being powered and are able to provide forced flow through the reactor core.
An OPERABLE SDC train is composed of an OPERABLE SDC pump and an OPERABLE SDC heat exchanger. The two SDC heat exchangers operate as a single unit. A separate OPERABLE SDC heat exchanger is required for each OPERABLE SDC train. SDC pumps are OPERABLE if they are capable of being powered and are able to provide forced flow through the reactor core.
Palisades Nuclear Plant B 3.4.6-3 Revised 07/31/2007
PCS Loops - MODE 4 B 3.4.6 BASES (continued)
APPLICABILITY In MODE 4, this LCO applies because it is possible to remove core decay heat and to provide proper boron mixing with either the PCS loops and SGs, or the SDC System.
Operation in other MODES is covered by:
LCO 3.4.4, "PCS Loops-MODES 1 and 2";
LCO 3.4.5, "PCS Loops-MODE 3";
LCO 3.4.7, "PCS Loops-MODE 5, Loops Filled";
LCO 3.4.8, "PCS Loops-MODE 5, Loops Not Filled";
LCO 3.9.4, "Shutdown Cooling (SDC) and Coolant Circulation-High Water Level" (MODE 6); and LCO 3.9.5, "Shutdown Cooling (SDC) and Coolant Circulation-Low Water Level" (MODE 6).
ACTIONS A.1 If only one PCS loop is OPERABLE and in operation with no OPERABLE SDC trains, redundancy for heat removal is lost. Action must be initiated immediately to restore a second PCS loop or one SDC train to OPERABLE status. The immediate Completion Time reflects the importance of maintaining the availability of two paths for decay heat removal.
B.1 If only one SDC train is OPERABLE and in operation with no OPERABLE PCS loops, redundancy for heat removal is lost. The plant must be placed in MODE 5 within the next 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Placing the plant in MODE 5 is a conservative action with regard to decay heat removal. With only one SDC train OPERABLE, redundancy for decay heat removal is lost and, in the event of a loss of the remaining SDC train, it would be safer to initiate that loss from MODE 5 (< 200- F) rather than MODE 4 (> 2009 F to < 300 2 F). The Completion Time of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is reasonable, based on operating experience, to reach MODE 5 from MODE 4, with only one SDC train operating, in an orderly manner and without challenging plant systems.
Palisades Nuclear Plant B 3.4.6-4 Revised 07/31/2007
PCS Loops - MODE 4 B 3.4.6 BASES ACTIONS C.1, C.2.1, and C.2.2 (continued)
If no PCS loops or SDC trains are OPERABLE, or no PCS loop is in operation and the SDC flow through the reactor core is < 2810 gpm, except during .conditions permitted by Note 1 in the LCO section, all operations involving reduction of PCS boron concentration must be suspended. Action to restore one PCS loop or SDC train to OPERABLE status and operation shall be initiated immediately and continue until one loop or train is restored to operation and flow through the reactor core is restored to > 2810 gpm. Boron dilution requires forced circulation for proper mixing, and the margin to criticality must not be reduced in this type of operation. The immediate Completion Times reflect the importance of decay heat removal.
SURVEILLANCE SR 3.4.6.1 REQUIREMENTS This SR requires verification every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> that one required loop or train is in operation. This ensures forced flow is providing heat removal and mixing of the soluble boric acid. Verification may include flow rate (SDC only), or indication of flow, temperature, or pump status for the PCP. The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Frequency has been shown by operating practice to be sufficient to regularly assess PCS loop/SDC train status. In addition, control room indication and alarms will normally indicate loop/train status.
SR 3.4.6.2 This SR requires verification every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> of secondary side water level in the required SG(s) > -84% using the wide range level instrumentation.
An adequate SG water level is required in order to have a heat sink for removal of the core decay heat from the primary coolant. The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> interval has been shown by operating practice to be sufficient to regularly assess degradation and verify SG status.
Palisades Nuclear Plant B 3.4.6-5 Revised 07/31/2007
PCS Loops - MODE 4 B 3.4.6 BASES SURVEILLANCE SR 3.4.6.3 REQUIREMENTS (continued) Verification that the required pump is OPERABLE ensures that an additional PCS loop or SDC train can be placed in operation, if needed to maintain decay heat removal and primary coolant circulation. Verification is performed by verifying proper breaker alignment and power available to the required pump that is not in operation such that the pump is capable of being started and providing forced PCS flow if needed. Proper breaker alignment and power availability means the breaker for the required pump is racked-in and electrical power is available to energize the pump motor.
The Frequency of 7 days is considered reasonable in view of other administrative controls available and has been shown to be acceptable by operating experience.
REFERENCES None 0
Palisades Nuclear Plant B 3.4.6-6 Revised 07/31/2007
PCS Loops - MODE 5, Loops Filled B 3.4.7 B 3.4 PRIMARY COOLANT SYSTEM (PCS)
B 3.4.7 PCS Loops - MODE 5, Loops Filled BASES BACKGROUND In MODE 5 with the PCS loops filled, the primary function of the primary coolant is the removal of decay heat and transfer this heat either to the Steam Generator (SG) secondary side coolant via natural circulation (Ref.
- 1) or the Shutdown Cooling (SDC) heat exchangers. While the principal means for decay heat removal is via the SDC System, the SGs via natural circulation are specified as a backup means for redundancy.
Even though the SGs cannot produce steam in this MODE, they are capable of being a heat sink due to their large contained volume of secondary side water. If heatup of the PCS were to continue, the contained inventory of the SGs would be available to remove decay heat by producing steam. As long as the SG secondary side water is at a lower temperature than the primary coolant, heat transfer will occur. The rate of heat transfer is directly proportional to the temperature difference.
The secondary function of the primary coolant is to act as a carrier for soluble neutron poison, boric acid.
In MODE 5 with PCS loops filled, the SDC trains are the principal means for decay heat removal. The number of trains in operation can vary to suit the operational needs. The intent of this LCO is to provide'-forced flow from at least one SDC train for decay heat removal and transport.
The flow provided by one SDC train is adequate for decay heat removal.
The other intent of this LCO is to require that a second path be available to provide redundancy for decay heat removal.
The LCO provides for redundant paths of decay heat removal capability.
The first path can be an SDC train that must be OPERABLE and in operation. The second path can be another OPERABLE SDC train, or through the SGs, via natural circulation each having an adequate water level. "Loops filled" means the PCS loops are not blocked by dams and totally filled with coolant.
Palisades Nuclear Plant B 3.4.7-1 Revised 07/31/2007
PCS Loops - MODE 5, Loops Filled B 3.4.7 BASES (continued)
APPLICABLE The boron concentration must be uniform throughout the PCS SAFETY ANALYSES volume to prevent stratification of primary coolant at lower boron concentrations which could result in a reactivity insertion. Sufficient mixing of the primary coolant is assured if one SDC pump is in operation.
PCS circulation is considered in the determination of the time available for mitigation of the inadvertent boron dilution event. By imposing a minimum flow through the reactor core of 2810 gpm, sufficient time is provided for the operator to terminate a boron dilution under asymmetric flow conditions.
PCS Loops - MODE 5 (Loops Filled) satisfies Criterion 4 of 10 CFR 50.36(c)(2).
LCO The purpose of this LCO is to require one SDC train be OPERABLE and in operation with either an additional SDC train OPERABLE or the secondary side water level of each SG > -84%. SDC in operation with a flow through the reactor core > 2810 gpm, provides enough flow to remove the decay heat from the core with forced circulation and provide sufficient mixing of the soluble boric acid. The second SDC train is normally maintained OPERABLE as a backup to the operating SDC train to provide redundant paths for decay heat removal. However, if the standby SDC train is not OPERABLE, a sufficient alternate method to provide redundant paths for decay heat removal is two SGs with their secondary side water levels >_-84%. Should the operating SDC train fail, the SGs could be used to remove the decay heat via natural circulation.
A SDC train may be considered OPERABLE (but not necessarily in operation) during re-alignment to, and when it is re-aligned for, LPSI service or for testing, if it is capable of being (locally or remotely)*
realigned to the SDC mode of operation and is not otherwise inoperable.
Since SDC is a manually initiated system, it need not be considered inoperable solely because some additional manual valve realignments must be made in addition to the normal initiation actions. Because of the dual functions of the components that comprise the LPSI and shutdown cooling systems, the LPSI alignment may be preferred.
Note 1 permits all SDC pumps to not be in operation < 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> per 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> period. The Note prohibits boron dilution when forced flow is stopped because an even concentration distribution cannot be ensured. Core outlet temperature is to be maintained at least Palisades Nuclear Plant B 3.4.7-2 Revised 07/31/2007
PCS Loops - MODE 5, Loops Filled B 3.4.7 BASES LCO 100 F below saturation temperature so that no vapor bubble may form (continued) and possibly cause a natural circulation flow obstruction. The response of the PCS without the SDC pumps depends on the core decay heat load and the length of time that the pumps are stopped.
As decay heat diminishes, the effects on PCS temperature and pressure diminish. Without cooling by forced flow, higher heat loads will cause the primary coolant temperature and pressure to increase at a rate proportional to the decay heat load. Because pressure can increase, the applicable system pressure limits (Pressure and Temperature (P/T) limits or Low Temperature Overpressure Protection (LTOP) limits) must be observed and forced SDC flow or heat removal via the SGs must be re-established prior to reaching the pressure limit.
In MODE 5 with loops filled, it is sometimes necessary to stop all SDC forced circulation. This is permitted to change operation from one SDC train to the other, perform surveillance or startup testing, perform the transition to and from the SDC, or to avoid operation below the PCP minimum net positive suction head limit. The time period is acceptable because natural circulation is acceptable for decay heat removal, the primary coolant temperature can be maintained subcooled, and boron stratification affecting reactivity control is not expected.
Note 2 allows both SDC trains to be inoperable for a period of up to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> provided that one SDC train is in operation providing the required flow, the core outlet temperature is at least 10°F below the corresponding saturation temperature, and each SG secondary water level is > 84%. This permits periodic surveillance tests or maintenance to be performed on the inoperable trains during the only time when-such evolutions are safe and possible.
Note 3 requires that one of the following conditions be satisfied before forced circulation (starting the first PCP) may be started:
- a. SG secondary temperature is equal to or less than the reactor inlet temperature (To);
- b. SG secondary temperature is < 100°F above T0, and shutdown cooling is isolated from the PCS, and PCS heatup/cooldown rate is
< 10°F/hour; or
- c. SG secondary temperature is < 100°F above Tc, and shutdown cooling is isolated from the PCS, and pressurizer level is < 57%.
Palisades Nuclear Plant B 3.4.7-3 Revised 07/31/2007
PCS Loops - MODE 5, Loops Filled B 3.4.7 BASES LCO Satisfying any of the above conditions will preclude a large pressure (continued) surge in the PCS when the PCP is started. Energy additions from the steam generators could occur if a PCP was started when the steam generator secondary temperature is significantly above the PCS temperature. The maximum pressurizer level at which credit is taken for having a bubble (57%, which provides about 700 cubic feet of steam space) is based on engineering judgement and verified by LTOP analysis.
This level provides the same steam volume to dampen pressure transients as would be available at full power.
Note 4 specifies a limitation on the simultaneous operation of primary coolant pumps P-50A and P-50B which allows the pressure limits in LCO 3.4.3, "PCS Pressure and Temperature Limits," and LCO 3.4.12, "Low Temperature Overpressure Protection System," to be higher than they would be without this limit.
Note 5 provides for an orderly transition from MODE 5 to MODE 4 during a planned heatup by permitting SDC trains to not be in operation when at least one PCP is in operation. This Note provides for the transition to MODE 4 where a PCP is permitted to be in operation and replaces the PCS circulation function provided by the SDC trains.
An OPERABLE SDC train is composed of an OPERABLE SDC pump and an OPERABLE SDC heat exchanger. The two SDC heat exchangers operate as a single unit. A separate OPERABLE SDC heat exchanger is required for each OPERABLE SDC train. SDC pumps are OPERABLE if they are capable of being powered and are able to provide forced flow through the reactor core.
An SG can perform as a heat sink via natural circulation when:
- a. SG has the minimum water level specified in SR 3.4.7.2.
- d. Ability to pressurize and control pressure in the PCS.
If both SGs do not meet the above provisions, then LCO 3.4.7 item b (i.e.
the secondary side water level of each SG shall be > -84%) is not met.
Palisades Nuclear Plant B 3.4.7-4 %, Revised 07/31/2007
PCS Loops - MODE 5, Loops Filled B 3.4.7 BASES (continued)
APPLICABILITY In MODE 5 with PCS loops filled, this LCO requires forced circulation to remove decay heat from the core and to provide proper boron mixing.
One SDC train provides sufficient circulation for these purposes.
Operation in other MODES is covered by:
LCO 3.4.4, "PCS Loops-MODES 1 and 2";
LCO 3.4.5, "PCS Loops-MODE 3";
LCO 3.4.6, "PCS Loops-MODE 4";
LCO 3.4.8, "PCS Loops-MODE 5, Loops Not Filled";
LCO 3.9.4, "Shutdown' Cooling (SDC) and Coolant Circulation-High Water Level" (MODE 6); and LCO 3.9.5, "Shutdown Cooling (SDC) and Coolant Circulation-Low Water-Level" (MODE 6).
Palisades Nuclear Plant -1 3.4.7-5 Revised 07/31/2007
PCS Loops - MODE 5, Loops Filled B 3.4.7 BASES (continued)
ACTIONS A.1 and A.2 If one SDC train is inoperable and any SG has a secondary side water level < -84% (refer to LCO Bases section), redundancy for heat removal is lost. Action must be initiated immediately to restore a second SDC train to OPERABLE status or to restore the water level in the required SGs. Either Required Action A.1 or Required Action A.2 will restore redundant decay heat removal paths. The immediate Completion Times reflect the importance of maintaining the availability of two paths for decay heat removal.
B.1 and B.2 If no SDC trains are OPERABLE or SDC flow through the reactor core is
< 2810 gpm, except as permitted in Note 1, all operations involving the reduction of PCS boron concentration must be suspended. Action to restore one SDC train to OPERABLE status and operation shall be initiated immediately and continue until one train is restored to operation and flow through the reactor core is restored to >_2810 gpm. Boron dilution requires forced circulation for proper mixing and the margin to criticality must not be reduced in this type of operation. The immediate Completion Times reflect the importance of maintaining operation for decay heat removal.
SURVEILLANCE SR 3.4.7.1 REQUIREMENTS This SR requires verification every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> that one SDC train is in operation. Verification of the required flow rate ensures forced flow is providing heat removal and mixing of the soluble boric acid. The 12-hour Frequency has been shown by operating practice to be sufficient to regularly assess SDC train status. In addition, control room indication and alarms will normally indicate train status.
Palisades Nuclear Plant B 3.4.7-6 Revised 07/31/2007
PCS Loops - MODE 5, Loops Filled B 3.4.7 BASES SURVEILLANCE SR 3.4.7.2 REQUIREMENTS (continued) This SR requires verification every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> of secondary side water level in the required SGs >_-84% using the wide range level instrumentation.
An adequate SG water level is required in order to have a heat sink for removal of the core decay heat from the primary coolant. The Surveillance is required to be performed when the LCO requirement is being met by use of the SGs. If both SDC trains are OPERABLE, this SR is not needed. The 12-hour Frequency has been shown by operating practice to be sufficient to regularly assess degradation and verify SG status.
SR 3.4.7.3 Verification that the second SDC train is OPERABLE ensures that redundant paths for decay heat removal are available. The requirement also ensures that the additional train can be placed in operation, if needed, to maintain decay heat removal and primary coolant circulation.
Verification is performed by verifying proper breaker alignment and power available to the required pump that is not in operation such that the SDC pump is capable of being started and providing forced PCS flow if needed. Proper breaker alignment and power availability means the breaker for the required SDC pump is racked-in and electrical power is available to energize the SDC pump motor. The Surveillance is required to be performed when the LCO requirement is being met by one of two SDC trains, e.g., both SGs have < -84% water level. The Frequency of 7 days is considered reasonable in view of other administrative controls available and has been shown to be acceptable by operating experience.
REFERENCES 1. NRC Information Notice 95-35, "Degraded Ability of Steam Generators to Remove Decay Heat by Natural Circulation" Palisades Nuclear Plant B 3.4.7-7 Revised 07/31/2007
PCS Loops - MODE 5, Loops Not Filled B 3.4.8 B 3.4 PRIMARY COOLANT SYSTEM (PCS)
B 3.4.8 PCS Loops - MODE 5, Loops Not Filled BASES BACKGROUND In MODE 5 with the PCS loops not filled, the primary function of the primary coolant is the removal of decay heat and transfer of this heat to the Shutdown Cooling (SDC) heat exchangers. The Steam Generators (SGs) are not available as a heat sink when the loops are not filled. The secondary function of the primary coolant is to act as a carrier for the soluble neutron poison, boric acid. A loop is considered "not filled" if it has been drained so air has entered the loop which has not yet been removed.
In MODE 5 with loops not filled, only the SDC System can be used for coolant circulation. The number of trains in operation can vary to suit the operational needs. The intent of this LCO is to provide forced flow from at least one SDC train for decay heat removal and transport and to require that two paths be available to provide redundancy for heat removal.
APPLICABLE The boron concentration must be uniform throughout the PCS SAFETY ANALYSES volume to prevent stratification of primary coolant at lower boron concentrations which could result in a reactivity insertion. Sufficient mixing of the primary coolant is assured if one SDC pump is in operation.
PCS circulation is considered in the determination of the time available for mitigation of the inadvertent boron dilution event. By imposing a minimum flow through the reactor core of >_2810 gpm, or a minimum flow through the reactor core > 650 gpm with two of the three charging pumps incapable of reducing the boron concentration in the PCS below the minimum value necessary to maintain the required SHUTDOWN MARGIN, sufficient time is provided for the operator to terminate a boron dilution under asymmetric flow conditions.
PCS loops - MODE 5 (Loops Not Filled) satisfies Criterion 4 of 10 CFR 50.36(c)(2).
Palisades Nuclear Plant [] 3.4.8-1 Revised 07/31/2007
PCS Loops - MODE 5, Loops Not Filled B 3.4.8 BASES LCO The purpose of this LCO is to require a minimum of two SDC trains be OPERABLE and one of these trains be in operation. SDC in operation with a flow rate through the reactor core of > 2810 gpm, or with a flow rate through the reactor core of > 650 gpm with two of the three charging pumps incapable of reducing the boron concentration in the PCS below the minimum value necessary to maintain the required SHUTDOWN MARGIN, provides enough flow to remove the decay heat from the core with forced circulation and provide sufficient mixing of the soluble boric acid. The restriction on charging pump operations only applies to fhose cases where the potential exists to reduce the PCS boron concentration below minimum the boron concentration necessary to maintain the required SHUTDOWN MARGIN. It is not the intent of this LCO to restrict charging pump operations when the source of water to the pump suction is greater than or equal to the minimum boron concentration necessary to maintain the required SHUTDOWN MARGIN. An additional SDC train is required to be OPERABLE to meet the single failure criterion.
A SDC train may be considered OPERABLE (but not necessarily in operation) during re-alignment to, and when it is re-aligned for, LPSI service or for testing, if it is capable of being (locally or remotely) realigned to the SDC mode of operation and is not otherwise inoperable.
Since SDC is a manually initiated system, it need not be considered inoperable solely because some additional manual valve realignments must be made in addition to the normal initiation actions. Because of the dual functions of the components that comprise the LPSI and shutdown cooling systems, the LPSI alignment may be preferred.
Note 1 permits all SDC pumps to not be in operation for < 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. The Note prohibits boron dilution when forced flow is stopped because an even concentration distribution cannot be ensured. Core outlet temperature is to be maintained at least 10°F below saturation temperature so that no vapor bubble may form and possibly cause a flow obstruction. Operations which could drain the PCS and thereby cause a loss of, or failure to regain SDC capability are also prohibited.
In MODE 5 with loops not filled, it is sometimes necessary to stop all SDC forced circulation. This is permitted to change operation from one SDC train to the other, and to perform surveillance or startup testing. The time period is acceptable because the primary coolant will be maintained subcooled, and boron stratification affecting reactivity control is not expected.
Palisades Nuclear Plant B 3.4.8-2 Revised 07/31/2007
PCS Loops - MODE 5, Loops Not Filled B 3.4.8 BASES LCO Note 2 allows one SDC train to be inoperable for a period of 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> (continued) provided that the other train is OPERABLE and in operation. This permits periodic surveillance tests to be performed on the inoperable train during the only time when these tests are safe and possible, An OPERABLE SDC train is composed of an OPERABLE SDC pump and an OPERABLE SDC heat exchanger. The two SDC heat exchangers operate as a single unit. A separate OPERABLE SDC heat exchanger is required for each OPERABLE SDC train. SDC pumps are OPERABLE if they are capable of being powered and are able to provide forced flow through the reactor core.
APPLICABILITY In MODE 5 with PCS loops not filled, this LCO requires forced circulation to remove decay heat from the core and to provide proper boron mixing.
One SDC train provides sufficient circulation for these purposes.
Operation in other MODES is covered by:
LCO 3.4.4, "PCS Loops-MODES 1 and 2";
LCO 3.4.5, "PCS Loops-MODE 3";
LCO 3.4.6, "PCS Loops-MODE 4";
LCO 3.4.7, "PCS Loops-MODE 5, Loops Filled";
LCO 3.9.4, "Shutdown Cooling (SDC) and Coolant Circulation-High Water Level" (MODE 6); and LCO 3.9.5, "Shutdown Cooling (SDC) and Coolant Circulation-Low Water Level" (MODE 6).
ACTIONS A.1 If one SDC train is inoperable, redundancy for heat removal is lost.
Action must be initiated immediately to restore a second train to OPERABLE status. The Completion Time reflects the importance of maintaining the availability of two paths for heat removal.
Palisades Nuclear Plant B 3.4.8-3 Revised 07/31/2007
PCS Loops - MODE 5, Loops Not Filled B 3.4.8 BASES ACTIONS B.1 and B.2 (continued)
If no SDC trains are OPERABLE or SDC flow through the reactor core is not within limits, except as provided in Note 1, all operations involving the reduction of PCS boron concentration must be suspended. Action to restore one SDC train to OPERABLE status and operation shall be initiated immediately and continue until one train is restored to operation and flow through the reactor core is restored to within limits. Boron dilution requires forced circulation for proper mixing and the margin to criticality must not be reduced in this type of operation. The immediate Completion Time reflects the importance of maintaining operation for decay heat removal.
SURVEILLANCE SR 3.4.8.1 and SR 3.4.8.2 REQUIREMENTS These SRs require Verification every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> that one SDC train is in operation. Verification of the required flow rate ensures forced circulation is providing heat removal and mixing of the soluble boric acid. The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Frequency has been shown by operating practice to be sufficient to regularly assess SDC train status. In addition, control room indications and alarms will normally indicate train status.
SR 3.4.8.1 and SR 3.4.8.2 are each modified by a Note to indicate the SR is only required to be met when complying with the applicable portion of the LCO. Therefore, it is only necessary to perform either SR 3.4.8.1, or SR 3.4.8.2 based on the method of compliance with the LCO.
Palisades Nuclear Plant B 3.4.8-4 Revised 07/31/2007
PCS Loops - MODE 5, Loops Not Filled B 3.4.8 BASES SURVEILLANCE SR 3.4.8.3 REQUIREMENTS (continued) This SR requires verification every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> that two of the three charging pumps are incapable of reducing the boron concentration in the PCS below the minimum value necessary to maintain the required SHUTDOWN MARGIN. Making the charging pumps incapable reducing the boron concentration in the PCS may be accomplished by electrically disabling the pump motors, blocking potential dilution sources to the pump suction, or by isolating the pumps discharge flow path to the PCS.
Verification may include visual inspection of the pumps configuration (e.g., pump breaker position or valve alignment), or the use of other administrative controls. The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Frequency is based on engineering judgement considering operating practice, administrative control available, and the unlikeness of inadvertently aligning a charging pump for PCS injection during this period.
SR 3.4.8.3 is modified by a Note to indicate the SR is only required to be met when complying with LCO 3.4.8.b. When SDC flow through the reactor core is >_2810 gpm, there is no restriction on charging pump operation.
SR 3.4.8.4 Verification that the required number of trains are OPERABLE ensures that redundant paths for heat removal are available and that additional trains can be placed in operation, if needed, to maintain decay heat removal and primary coolant circulation. Verification is performed by verifying proper breaker alignment and indicated power available to the required pump that is not in operation such that the SDC pump is capable of being started and providing forced PCS flow if needed. Proper breaker alignment and power availability means the breaker for the required SDC pump is racked-in and electrical power is available to energize the SDC pump motor. The Frequency of 7 days is considered reasonable in view of other administrative controls available and has been shown to be acceptable by operating experience.
REFERENCES None Palisades Nuclear Plant B] 3.4.8-5 Revised 07/31/2007
Condensate Storage and Supply B 3.7.6 B 3.7 PLANT SYSTEMS B 3.7.6 Condensate Storage and Supply BASES BACKGROUND The Condensate Storage and Supply provides a safety grade source of water to the steam generators for removing decay and sensible heat from the Primary Coolant System (PCS). The Condensate Storage Tank (CST) and the Primary Makeup Storage Tank (T-81) provide a passive flow of water, by gravity, to the Auxiliary Feedwater (AFW) System (LCO 3.7.5, "Auxiliary Feedwater (AFW) System"). Three AFW pumps take a suction from a common line from the CST. T-81 provides makeup to the CST either by use of a pump or by gravity flow. Backup sources from the Service Water System (SWS) and Fire Water System an provide additional water supply to the AFW pump suctions if the normal source is lost. SWS provides an emergency source to AFW pump P-8C, and the Fire Water System provides an emergency source to AFW pumps P-8A and P-8B. The steam produced is released to the atmosphere by the Main Steam Safety Valves (MSSVs) or the atmospheric dump valves.
The AFW pumps operate with a continuous recirculation to the CST.
When the main steam isolation valves are open, the preferred means of heat removal is to discharge steam to the condenser by the nonsafety grade path of the turbine bypass valve. This has the advantage of conserving condensate while minimizing releases to the environment.
Because the CST is a principal component in removing residual heat from the PCS, it is designed to withstand earthquakes. The tornado protected supply is provided by the SWS and Fire Water System. The CST is designed to Seismic Category I requirements to ensure availability of the feedwater supply.
A description of the Condensate Storage and Supply is found in the FSAR, Section 9.7 (Ref. 1).
Palisades Nuclear Plant B 3.7.6-1 P NRevised 07/31/2007
Condensate Storage and Supply B 3.7.6 BASES APPLICABLE The Condensate Storage and Supply provides condensate to remove SAFETY ANALYSES decay heat and to cool down the plant following all events in the accident analysis, discussed in the FSAR, Chapters 5 and 14. For anticipated operational occurrences and accidents which do not affect the OPERABILITY of the steam generators, the analysis assumption is generally 30 minutes at MODE 3, steaming through the MSSVs followed by a cooldown to Shutdown Cooling (SDC) entry conditions at the design cooldown rate.
The Condensate Storage and Supply satisfies Criterion 3 of 10 CFR 50.36(c)(2).
LCO To satisfy accident analysis assumptions, the CST and T-81 must contain sufficient cooling water to remove decay heat for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> following a reactor trip from 2580.6 MWth. This amount of time allows for cool down of the PCS to SDC entry conditions, assuming a coincident loss of offsite power and the most adverse single failure. In doing this the CST and T-81 must retain sufficient water to ensure adequate net positive suction head for the AFW pumps, and makeup for steaming required to remove decay heat.
OPERABILITY of the Condensate Storage and Supply System is determined by maintaining the combined tank levels at or above the minimum required volume.
APPLICABILITY In MODES 1, 2, and 3, and in MODE 4, when steam generator is being relied upon for heat removal, the Condensate Storage and Supply is required to be OPERABLE.
In MODES 5 and 6, the Condensate Storage and Supply is not required because the AFW System is not required.
Palisades Nuclear Plant B 3.7.6-2 Revised 07/31/2007
Condensate Storage and Supply B 3.7.6 BASES ACTIONS A.1 and A.2 If the condensate volume is not within the limit, the OPERABILITY of the backup water supplies must be verified by administrative means within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and once every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> thereafter.
OPERABILITY of the backup feedwater supplies must include verification of the OPERABILITY of flow paths from the Fire Water System and SWS to the AFW pumps, and availability of the water in the backup supplies.
The Condensate Storage and Supply volume must be returned to OPERABLE status within 7 days, as the backup supplies may be performing this function in addition to their normal functions. The 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Completion Time is reasonable, based on operating experience, to verify the OPERABILITY of the Fire Water System and SWS. Additionally, verifying the backup water supplies every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is adequate to ensure the backup water supplies continue to be available. The 7 day Completion Time is reasonable, based on OPERABLE backup water supplies being available, and the low probability of an event requiring the use of the water from the CST and T-81 occurring during this period.
As stated in SR 3.0.2, the 25% extension allowed by SR 3.0.2 may be applied to Required Actions whose Completion Time is stated as "once per. .. " however, the 25% extension does not apply to the initial performance.of a Required Action with a periodic Completion Time that requires performance on a "once per. .. " basis. The 25% extension applies to each performance of the Required Action after the initial performance. Therefore, while Required Action 3.7.6 A.1 must be initially performed within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> without any SR 3.0.2 extension, subsequent performances at the "Once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />" interval may utilize the 25% SR 3.0.2 extension.
B.1 and B.2 If the condensate volume cannot be restored to OPERABLE status within the associated Completion Time, the plant must be placed in a MODE in which the LCO does not apply. To achieve this status, the plant must be placed in at least MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, and in MODE 4, without reliance on steam generator for heat removal, within 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. The allowed Completion Times are reasonable, based on operating experience, to reach the required plant conditions from full power conditions in an orderly manner and without challenging plant systems.
Revised 07/31/2007 Plant Nuclear Plant Palisades Nuclear B 3.7.6-3 B 3.7.6-3 Revised 07/31/2007
Condensate Storage and Supply B 3.7.6 BASES SURVEILLANCE SR 3.7.6.1 REQUIREMENTS This SR verifies that the combination of CST and T-81 contain the required useable volume of cooling water. (This volume >_100,000 gallons.) The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Frequency is based on operating experience, and the need for operator awareness of plant evolutions that may affect the Condensate Storage and Supply inventory between checks. The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Frequency is considered adequate in view of other indications in the control room, including alarms, to alert the operator to abnormal CST and T-81 level deviations.
REFERENCES 1. FSAR, Section 9.7 Palisades Nuclear Plant B 3.7.6-4 Revised 07/31/2007
SDC and Coolant Circulation - High Water Level B 3.9.4 B 3.9 REFUELING OPERATIONS B 3.9.4 Shutdown Cooling (SDC) and Coolant Circulation - High Water Level BASES BACKGROUND The purposes of the SDC System in MODE 6 are to remove decay heat and sensible heat from the Primary Coolant System (PCS) as required by the Palisade Nuclear Plant design, to provide mixing of borated coolant, to provide sufficient coolant circulation to minimize the effects of a boron dilution accident, and to prevent boron stratification (Ref. 1). Heat is removed from the PCS by circulating primary coolant through the SDC heat exchanger(s), where the heat is transferred to the Component Cooling Water System. The coolant is then returned to the PCS via the PCS cold leg(s). Operation of the SDC System for normal cooldown or decay heat removal is manually accomplished from the control room.
The heat removal rate is adjusted by controlling the flow of primary coolant through the SDC heat exchanger(s). Mixing of the primary coolant is maintained by this continuous circulation of primary coolant through the SDC System.
APPLICABLE If the primary coolant temperature is not maintained below 200 0 F, SAFETY ANALYSES boiling of the primary coolant could result. This could lead to inadequate cooling of the reactor fuel due to the resulting loss of coolant in the reactor vessel. Additionally, boiling of the primary coolant could lead to a reduction in boron concentration in the coolant due to the boron plating out on components near the areas of the boiling activity, and because of the possible addition of water to the reactor vessel with a lower boron concentration than is required to keep the reactor subcritical.
The loss of primary coolant and the reduction of boron concentration in the primary coolant would eventually challenge the integrity of the fuel cladding, which is a fission product barrier. One train of the SDC System is required to be in operation in MODE 6, with the refueling cavity water level greater than or equal to the 647 ft elevation, to prevent this challenge. The LCO allows the removal of an SDC train from operation for short durations under the condition that the boron concentration of the primary coolant is not reduced.
This conditional allowance does not result in a challenge to the fission product barrier.
SDC and Coolant Circulation - High Water Level satisfies Criterion 4 of 10 CFR 50.36(c)(2).
Palisades Nuclear Plant B 3.9.4-1 Revised 07/31/2007
SDC and Coolant Circulation - High Water Level B 3.9.4 BASES LCO Only one SDC train is required for decay heat removal in MODE 6, with the refueling cavity water level greater than or equal to the 647 ft elevation. Only one SDC train is required because the volume of water above the reactor vessel flange provides backup decay heat removal capability. At least one SDC train must be OPERABLE and in operation to provide:
- a. Removal of decay heat;
- b. Mixing of borated coolant to minimize the possibility of a criticality; and
- c. Indication of reactor coolant temperature.
An OPERABLE SDC train consists of an SDC pump, a heat exchanger, valves, piping, instruments, and controls to ensure an OPERABLE flow path and to determine the PCS temperature. The two SDC heat exchangers operate as a single unit. A separate OPERABLE SDC heat exchanger is required for each OPERABLE SDC train. The flow path starts in the Loop 2 PCS hot leg and is returned to at least one PCS cold leg.
A SDC train may be considered OPERABLE (but not necessarily in operation) during re-alignment to, and when it is re-aligned for, LPSI service or for testing, if it is capable of being (locally or remotely) realigned to the SDC mode of operation and is not otherwise inoperable.
Since SDC is a manually initiated system, it need not be considered inoperable solely because'some additional manual valve realignments must be made in addition to the normal initiation actions. Because of the dual functions of the components that comprise the LPSI and shutdown cooling systems, the LPSI alignment may be preferred.
The LCO is modified by two Notes. Note 1 allows the required operating SDC train to not be in operation for up to 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> in each 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> period, provided no operations are permitted that would cause a reduction of the PCS boron concentration. Boron concentration reduction is prohibited because uniform.concentration distribution cannot be ensured without forced circulation. This permits operations such as core mapping or alterations in'the vicinity of the reactor vessel hot leg nozzles, and PCS to SDC isolation valve testing.
During this 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> period, decay heat is removed by natural circulation to the large mass of water in the refueling cavity. Note 2 allows the required SDC train to be made inoperable for < 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> per 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> period for testing and maintenance provided one SDC train in operation providing flow through the reactor core, and the core outlet temperature is < 2000 F.
The purpose of this Note is to allow the heat flow path from the SDC heat Palisades Nuclear Plant B 3.9.4-2 Revised 07/31/2007
SDC and Coolant Circulation - High Water Level B 3.9.4 BASES exchanger to be temporarily interrupted for maintenance or testing on the Component Cooling Water or Service Water Systems.
LCO During this 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> period, the core outlet temperature must be (continued) maintained < 200 0 F. Requiring one SDC train to be in operation ensures adequate mixing of the borated coolant.
APPLICABILITY One SDC train must be OPERABLE and in operation in MODE 6, with the refueling cavity water level greater than or equal to 647 ft elevation, to provide decay heat removal. The 647 ft elevation was selected because it corresponds to the elevation requirement established for fuel movement in LCO 3.9.6, "Refueling Cavity Water Level." Requirements for the SDC System in other MODES are covered by LCOs in Section 3.4, "Primary Coolant System (PCS)." SDC train requirements in MODE 6, with the refueling cavity water level less than the 647 ft elevation are located in LCO 3.9.5, "Shutdown Cooling (SDC) and Coolant Circulation - Low Water Level."
ACTIONS SDC train requirements are met by having one SDC train OPERABLE and in operation, except as permitted in the Note to the LCO.
A.1 If one required SDC train is inoperable or not in operation, actions shall be immediately initiated and continued until the SDC train is restored to OPERABLE status and to operation. An immediate Completion Time is necessary for an operator to initiate corrective actions.
A.2 If SDC train requirements are not met, there will be no forced circulation to provide mixing to establish uniform boron concentrations. Reduced boron concentrations can occur through the addition of water with a lower boron concentration than that contained in the PCS. Therefore, actions that reduce boron concentration shall be suspended immediately.
Palisades Nuclear Plant B 3.9.4-3 Revised ý07/31/2007
SDC and Coolant Circulation - High Water Level B 3.9.4 BASES ACTIONS A.3 (continued)
If SDC train requirements are not met, actions shall be taken immediately to suspend loading irradiated fuel assemblies in the core. With no forced circulation cooling, decay heat removal from the core occurs by natural circulation to the heat sink provided by the water above the core. A minimum refueling cavity water level equivalent to the 647 ft elevation provides an adequate available heat sink. Suspending any operation that would increase the decay heat load, such as loading a fuel assembly, is a prudent action under this condition.
A.4 If SDC train requirements are not met, all containment penetrations providing direct access from the containment atmosphere to the outside atmosphere must be closed to prevent fission products, if released by a loss of decay heat removal event, from escaping to the environment. The 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Completion Time is based on the low probability of the coolant boiling in that time and allows time for fixing most SDC problems.
SURVEILLANCE SR 3.9.4.1 REQUIREMENTS This Surveillance demonstrates that the SDC train is in operation and circulating primary coolant. The flow rate is sufficient to provide decay heat removal capability and to prevent thermal and boron stratification in the core. The 1000 gpm flow rate has been determined by operating experience rather than analysis. The Frequency of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is sufficient, considering the flow, temperature, pump control, and alarm indications available to the operator in the control room for monitoring the SDC System.
REFERENCES 1. FSAR, Sections 6.1 and 14.3 Palisades Nuclear Plant B 3.9.4-4 Revised 07/31/2007
SDC and Coolant Circulation - Low Water Level B 3.9.5 B 3.9 REFUELING OPERATIONS B 3.9.5 Shutdown Cooling (SDC) and Coolant Circulation - Low Water Level BASES BACKGROUND The purposes of the SDC System in MODE 6 are to remove decay heat and sensible heat from the Primary Coolant System (PCS), as required by the Palisades Nuclear Plant design, to provide mixing of borated coolant, to provide sufficient coolant circulation to minimize the effects of a boron dilution accident, and to prevent boron stratification (Ref. 1).
Heat is removed from the PCS by circulating primary coolant through the SDC heat exchanger(s), where the heat is transferred to the Component Cooling Water System via the SDC heat exchanger(s). The coolant is then returned to the PCS via the PCS cold leg(s). Operation of the SDC System for normal cooldown or decay heat removal is manually accomplished from the control room. The heat removal rate is adjusted by controlling the flow of primary coolant through the SDC heat exchanger(s) and bypassing the heat exchanger(s). Mixing of the primary coolant is maintained by this continuous circulation of primary coolant through the SDC System.
APPLICABLE If the primary coolant temperature is not maintained below 200 0 F, SAFETY ANALYSES boiling of the primary coolant could result. This could lead to inadequate cooling of the reactor fuel due to the resulting loss of coolant in the reactor vessel. Additionally, boiling of the primary coolant could lead to a reduction in boron concentration in the coolant due to the boron plating out on components near the areas of the boiling activity, and because of the possible addition of water to the reactor vessel with a lower boron concentration than is required to keep the reactor subcritical.
The loss of primary coolant and the reduction of boron concentration in the primary coolant would eventually challenge the integrity of the fuel cladding, which is a fission product barrier. Two trains of the SDC System are required to be OPERABLE, and one train is required to be in operation in MODE 6, with the refueling cavity water level less than the 647 ft elevation to prevent this challenge.
SDC and Coolant Circulation - Low Water Level satisfies Criterion 4 of 10 CFR 50.36(c)(2).
Palisades Nuclear Plant B 3.9.5-1 Revised 07/31/2007
SDC and Coolant Circulation - Low Water Level B 3.9.5 BASES LCO In MODE 6, with the refueling cavity water level less than the 647 ft elevation, both SDC trains must be OPERABLE. Additionally, one train of the SDC System must be in operation in order to provide:
- a. Removal of decay heat;
- b. Mixing of borated coolant to minimize the possibility of a criticality; and
- c. Indication of primary coolant. temperature.
An OPERABLE SDC train consists of an SDC pump, a heat exchanger, valves, piping, instruments, and controls to ensure an OPERABLE flow-path and to determine the PCS temperature. The two SDC heat exchangers operate as a single unit. A separate OPERABLE SDC heat exchanger is required for each OPERABLE SDC train. The flow path starts in one of the PCS hot legs and is returned to the PCS cold legs.
A SDC train may be considered OPERABLE (but not necessarily in operation) during re-alignment to, and when it is re-aligned for, LPSI service or for testing, if it is capable of being (locally or remotely) realigned to the SDC mode of operation and is not otherwise inoperable. Since SDC is a manually initiated system, it need not be considered inoperable solely because some additional manual valve realignments must be made in addition to the normal initiation actions.
Because of the dual functions of the components that comprise the LPSI and shutdown cooling systems, the LPSI alignment may be preferred.
Both SDC pumps may be aligned to the safety injection refueling water tank to support filling the refueling cavity or for performance of required testing.
APPLICABILITY Two SDC trains are required to be OPERABLE, and one SDC train must be in operation in MODE 6, with the refueling cavity water level less than the 647 ft elevation to provide decay heat removal.
Requirements for the SDC System in other MODES are covered by LCOs in Section 3.4, "Primary Coolant System." MODE 6 requirements, with the refueling cavity water level greater than or equal to the 647 ft elevation are covered in LCO 3.9.4, "Shutdown Cooling and Coolant Circulation - High Water Level."
Palisades Nuclear Plant B 3.9.5-2 Revised 07/31/2007
SDC and Coolant Circulation - Low Water Level B 3.9.5 BASES ACTIONS A.1 and A.2 If one SDC train is inoperable, action shall be immediately initiated and continued until the SDC train is restored to OPERABLE status, or until a water level of greater than or equal to the 647 ft elevation is established.
When the water level is established at the 647 ft elevation or greater, the plant conditions will change so that LCO 3.9.4, "Shutdown Cooling and Coolant Circulation - High Water Level," is applicable, and only one SDC train is required to be OPERABLE and in operation. An immediate Completion Time is necessary for an operator to initiate corrective actions.
B.1 If no SDC train is in operation or no SDC trains are OPERABLE, there will be no forced circulation toprovide mixing to establish uniform boron concentrations. Reduced boron concentrations can occur by the addition of water with lower boron concentration than that contained in the PCS. Therefore, actions that reduce boron concentration shall be suspended immediately.
B.2 If no SDC train is in operation or no SDC trains are OPERABLE, action shall be initiated immediately and continued without interruption to restore one SDC train to OPERABLE status and operation. Since the plant is in Conditions A and B concurrently, the restoration of two OPERABLE SDC trains and one operating SDC train should be accomplished expeditiously.
B.3 If no SDC train is in operation, all containment penetrations providing direct access from the containment atmosphere to the outside atmosphere must be closed Immediately. With the SDC train requirements not met, the potential exists for the coolant to boil and release radioactive gas to the containment atmosphere. Closing containment penetrations that are open to the outside atmosphere ensures that dose limits are not exceeded.
Palisades Nuclear Plant B 3.9.5-3 Revised 07/31/2007
SDC and Coolant Circulation - Low Water Level B 3.9.5 BASES SURVEILLANCE SR 3.9.5.1 REQUIREMENTS This Surveillance demonstrates that one SDC train is operating and circulating primary coolant. The flow rate is sufficient to provide decay heat removal capability and to prevent thermal and boron stratification in the core.
In addition, during operation of the SDC train with the water level in the vicinity of the reactor vessel nozzles, the SDC train flow rate determination must also consider the SDC pump suction requirements.
The 1000 gpm flow rate has been determined by operating experience rather than analysis. The Frequency of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is sufficient, considering the flow, temperature, pump control, and alarm indications available to the operator to monitor the SDC System in the control room.
SR 3.9.5.2 Verification that the required pump is OPERABLE ensures that an additional SDC pump can be placed in operation, if needed, to maintain decay heat removal and primary coolant circulation. Verification is performed by verifying proper breaker alignment and power available to the required pump. The Frequency of 7 days is considered reasonable in view of other administrative controls available and has been shown to be acceptable by operating experience.
REFERENCES 1. FSAR, Sections 6.1 and 14.3 Palisades Nuclear Plant B 3.9.5-4 Revised 07/31/2007