ML20069K165
| ML20069K165 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 06/09/1994 |
| From: | PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | |
| Shared Package | |
| ML20069K148 | List: |
| References | |
| RTR-NUREG-1433 NUDOCS 9406150288 | |
| Download: ML20069K165 (13) | |
Text
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ATTACHMENT 2 PEACH BOTTOM ATOMIC POWER STATION UNITS 2 AND 3 Docket Nos. 50-277 50-278 Ucense Nos. DPR-44 DPR-56 TECHNICAL SPECIFICATIONS CHANGE REQUEST 94-06 Ust of Attached Pages Unit 2 .UE!La 103 103 104 104 111 111 112 112 113 113 133b 133b
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1 Unit 2 PBAPS LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS 3.3.B Control Rods (Cont'd.) 4.3.8 Control Rods (Cont'd.)
- 4. Control rods shall not be with- 4. Prior to control rod drawn for startup or refueling withdrawal for startup unless at least two source or during refueling, range channels have an observed verify that at least count rate equal to or greater two source range than three counts per second.* channels have an observed count rate of at least three counts per second.*
- 5. During operation with limiting 5. When a limiting control control rod patterns, as deter- rod pattern exists, an mined by the designated quali- instrument functional test fled personnel, either: of the RBM shall be performed prior to with-drawal of the designated ,
- a. Both RBM channels shall be rod (s),
operable, or i
- b. Control rod withdrawal shall
- May be reduced provided be blocked, or at least three source :
- c. The operating power level range channels for ,
shall be limited so that startup or at least two the MCPR will remain above source range channels for i the fuel cladding integrity refueling have an ,
safety limit assuaiing a observed count rate and a single error that results signal-to-noise ratio cn ,
in complete withdrawal of or above the curve shown '
a single operable control on Figure 3.3.1. i rod. .
C. Scram Insertion Times C. Scram Insertion Times -
- 1. The average scram insertion time, 1. After each refueling outage based on the deenergization of or after a reactor shutdown the scram pilot valve solenoids that is greater than 120 ;
as time zero, of all operable days, each control rod shall '
control rods in the reactor be scram time tested with power operation condition the reactor steam dome shall be no greater than: pressure greater than or
! equal to 800 psig prior to
% Inserted from Avg. Scram Inser- exceeding 40% of Rated Fully Withdrawn tion Times (sec) Power. Scram time testing is not required for control i i 5 0.375 rods inserted per 20 0.90 Specification 3.3.B.I.
50 2.0 i 90 3.5 'l
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Unit 2 PBAPS LIMITING CONDITIONS FOR OPERATION SURVEILLANCE RE0VIREMENTS 3.3.C (Cont'd) 4.3.C (Cont'd)
- 2. The average of the scram inser- 2. After any fuel movement within the tion times for the three fastest reactor pressure vessel, only control rods of all groups of those control rods associated with four control rods in a two-by- the core cells affected by the two array shall be no greater fuel movements shall be scram time than: tested with the reactor steam dome pressure greater than or equal to .
% Inserted From Avg. Scram Inser- 800 psig prior to exceeding 40% of Fully Withdrawn tion Times (Sec) Rated Power.
5 0.398 20 0.954 50 2.120 90 3.8
- 3. The maximum scram insertion time 3. At least once per 120 days of for 90% insertion of any operable power operation, perform scram control rod shall not exceed 7.00 time testing for a representative seconds, sample of control rods with the reactor steam dome pressure greater than or equal to 800 psig.
- 4. Prior to declaring affected individual control rods operable after work on the control rod or control rod drive system that i could affect scram insertion time, each affected control rod shall be scram time tested at any reactor steam dome pressure. Scram times <
as a function of reactor steam dome pressures less than 800 psig are provided in the Core Operating Limits Report. ;
- 5. Prior to exceeding 40% of Rated Power after work on the control .
rod or control rod drive system )
that could affect scram insertion i time, each affected control rod j shall be scram time tested with the reactor steam dome pressure greater than or equal to 800 psig.
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l PBAPS Unit 2
. . i 3.3 and 4.3 BASES (Cont'd)
C. Scram Insertion Times The control rod system is designed to bring the reactor subcritical at a rate fast enough to prevent fuel damage; 1.e.,
to prevent the MCPR from becoming less than the fuel cladding !
integrity safety limit. Analysis of the limiting power I transients shows that the negative reactivity rates resulting from the scram with the average response of all drives as given in the above Specification, provide the required protection. l The numerical values assigned to the specified scram performance are based on the analysis of data from ocher BWR's with control rod drives the same as those on Peach Bottom.
The occurrence of scram times within the limits, but significantly longer than the average, should be viewed as an indication of a systematic problem with control rod drives especially if the number of drives exhibiting such scram times exceeds one control rod of a (5x5) twenty-five control rod array.
In the analytical treatment of the transients, which are assumed to scram on high neutron flux, 340 milliseconds are allowed between a neutron sensor reaching the scram point and the start of negative reactivity insertion. The 340 milliseconds used in the analyses consist of 140 milliseconds for sensor and circuit delay and 200 milliseconds to start of control rod motion. The 200 milliseconds are included in the allowable scram insertion Limes specified in Specification 3.3.C. In addition the control rod drop accident has been analyzed in NEDO-10527 and its supplements 1 & 2 for the scram times given in Specification 3.3.C.
Measurement of the scram times with reactor steam dome pressure greater than or equal to 800 psig demonstrates acceptable scram times for the transients analyzed in UFSAR, Appendix K,Section VI and UFSAR Chapter 14.
Maximum scram insertion times occur at a reactor steam dome pressure of approximately 800 psig because of the competing effects of reactor steam dome pressure and stored accumulator energy. Therefore, demonstration of adequate scram times at reactor steam dome pressure greater than 800 psig ensures that the measured scram times will be within the specified limits at higher pressures. Limits are specified as a function of reactor pressure to account for the sensitivity of the scram insertion times with pressure and to allow a range of pressures over which scram time testing can be performed. To ensure that scram time testing is performed within a reasonable time after fuel movement within the reactor pressure vessel or after a shutdown greater ,
than or equal to 120 days or longer, all control rods are l required to be tested before exceeding 40% of Rated Power j following the shutdown. In the event fuel movement is limited to selected core cells, only those control rods associated with the core cells affected by the fuel movements are required to be scram time tested. However, if the reactor remains shutdown for greater than or equal to 120 days, all control rods are required to be scram time tested. I l
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i Unit 2 PBAPS 3.3 and 4.3 BASJJ (Cont'd)
Additional testing once per 120 days of a sample of the control rods is required to verify the continued performance of the scram function during the cycle. A representative sample contains at least 10% of the control rods. For planned testing, the control rods selected for the sample should be different for each test.
Data from inadvertent scrams should be used whenever possible to avoid unnecessary testing at power, even if the control rods with data may have been previously tested in a sample. The 120 day frequency is based on operating experience that has shown control rod scram times do not significantly change over an operating cycle.
When work that could affect the scram insertion time is performed on a control rod or the control rod drive system, testing must be done to demonstrate that each affected control rod retains l adequate scram performance over the range of applicable reactor pressures from zero to the maximum permissible pressure. The scram testing must be performed once before declaring the control rod operable. The required scram time testing must demonstrate the affected control rod is still within the acceptable limits for reactor pressures less than 800 psig found in the Core operating Limits Report.
Specific examples of work that could affect the scram times are (but ace not limited to) the following: removal of any control rod drive for maintenance or modification; replacement of a control rod; and maintenance or modification of a scram solenoid pilot valve, scram valve, accumulator, isolation valve or check valve in the piping required for scram.
When work that could affect the scram insertion time is performed on a control rod or the control rod drive system, testing must be done to demonstrate each affected control rod is still within the limits with the reactor steam dome pressure greater than or equal to 800 psig. Where work has been performed at high reactor pressure, the requirements of 4.3.C.4 and 4.3.C.5 can be satisfied with one test. For a control rod affected by work performed while shut down; however, a zero pressure and high pressure test may be required. This testing ensures that, prior to withdrawing the control rod for continued operation, the control rod scram performance is acceptable for operating reactor pressure conditions. Alternatively, a control rod scram test during hydrostatic pressure testing could also satisfy both .
I criteria.
operability of the scram discharge volume vent and drain valves is necessary for maintaining a reservoir to contain the water exhausted from all control rod drives during a scram.
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Unit 2 l 1
PBAPS 4
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PBAPS Unit 2 i LIMITING CONDITIONS FOR OPERATION SURVEILLANCE RE0VIREMENTS 3.5.J Local LHGR (Cont'd)
If at any time during operation it is determined by normal surveillance that limiting value for LHGR is being exceeded, action shall be initiated within one (1) hour to restore LHGR to within prescribed limits. If the LHGR is not returned to within prescribed limits within five (5) hours, reactor power shall be decreased at a rate which would bring the reactor to the cold shutdown condition within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> unless LHGR is returned to within limits during this period.
Surveillance and corresponding action shall continue until reactor operation is within the prescribed limits.
3.5.K Minimum Critical Power 4.5.K Minimum Critical Power Ratio (MCPR) Ratio (MCPR)
- 1. During power operation the MCPR for 1. MCPR shall be checked daily the applicable incremental cycle core during reactor power operation average exposure and for each type of at 225% rated thermal power.
fuel shall be equal to or greater than the value given in Specification 3.5.K.2 2. Except as provided in Spec-or 3.5.K.3 times Kf, where Kf is as ification 3.5.K.3, the verifi-specified in the CORE OPERATING LIMITS cation of the appilcability of REPORT. If at any time during operation 3.5.K.2.a Operating Limit MCPR it is determined by normal surveillance Values shall be per formed every that the limiting value for MCPR is being 120 operating days hy scram exceeded, action shall be initiated time testing a representative within one (1) hour to restore MCPR to sample of control rods and within prescribed limits. If the MCPR performing the following:
is not returned to within prescribed limits within five (5) hours, reactor a. The average scram time to power shall be decreased at a rate which the 20% insertion position would bring the reactor to the cold shut- shall be:
down condition within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> unless r ave 5 r 8 MCPR is returned to within limits during this period. Surveillance and corres- b. The average scram time to ponding action shall continue until the 20% insertion position reactor operation is within the is determined as follows:
prescribed limits.
n r ave - I Ni r i 1-1 n
I Ni i?
where: n - number of surveillance tests performed to date in the cycle.
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, Unit 3 PBAPS LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS 3.3.B Control Rods (Cont'd.) 4.3.B Control Rods (Cont'd.)
- 4. Control rods shall not be with- 4. Prior to control rod drawn for startup or refueling withdrawal for startup unless at least two source or during refueling, range channels have an observed verify that at least count rate equal to or greater two source range than three counts per second.* channels have an observed count rate of at least three counts per second.*
- 5. During operation with limiting 5. When a limiting control control rod patterns, as deter- rod pattern exists, an mined by the designated quali- instrument functional test fied personnel, either: of the RBM shall be perft rmed prior to with-drawal of the designated
- a. Both RBM channels shall be rod (s).
operable, or
- b. Control rod withdrawal shall
- Ma/ be reduced provided be blocked, or at least three source
- c. The operating power level ringe channels for shall be limited so that startup or at least two the MCPR will remain above source range channels for the fuel cladding integrity refueling have an safety limit assuming a observed count rate and a single error that results signal-to-noise ratio on in complete withdrawal of or above the curve shown a single operable control on Figure 3.3.1.
rod.
C. Scram Insertion Times C. Scram Insertion Times
- 1. The average scram insertion time, 1. After each refueling outage based on the deenergization of or after a reactor shutdown the scram pilot valve solenoids that is greater than 120 as time zero, of all operable days, each control rod shall control rods in the reactor be scram time tested with power operation condition the reactor steam dome shall be no greater than: pressure greater than or equal to 800 psig prior to
% Inserted from Avg. Scram Inser- exceeding 40% of Rated Fully Withdrawn tion Times (sec) Power. Scram time testing is not required for control 5 0.375 rods inserted per 20 0.90 Specification 3.3.B.I.
50 2.0 90 3.5
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Unit 3 ;
PBAPS LIMITING CONDITIONS FOR OPERATION SURVEILLANCE RE0VIREMENTS 3.3.0 (Cont'd) 4.3.C (Cont'd) l 2. The average of the scram inser- 2. After any fuel movement within the tion times for the three fastest reactor pressure vessel, only control rods of all groups of those control rods associated with four control rods in a two-by- the core cells affected by the i
two array shall be no greater fuel movements shall be scram time j than: tested with the reactor steam dome pressure greater than or equal to
% Inserted From Avg. Scram Inser- 800 psig prior to exceeding 40% of l
Fully Withdrawn tion Times (Sec) Rated Power.
5 0.398 20 0.954 50 2.120 90 3.8
- 3. The maximum scram insertion time 3. At least once per 120 days of i
for 90% insertion of any operable power operation, perform scram i control rod shall not exceed 7.00 time testing for a representative i seconds. sample of control rods with the reactor steam dome pressure greater than or equal to 800 psig.
- 4. Prior to declaring affected individual control rods operable after work on the control rod or control rod drive system that could affect scram insertion time, each affected control rod shall be scram time tested at any reactor steam dome pressure. Scram times as a function of reactor steam dome pressures less than 800 psig are provided in the Core Operating Limits Report.
- 5. Prior to exceeding 40% of Rated Power after work on the control rod or control rod drive system that could affect scram insertion time, each affected control rod shall be scram time tested with the reactor steam dome pressure greater than or equal to 800 psig.
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PBAPS Unit 3 3.3 and 4.3 BASES (Cont'd)
C. Scram Insertion Times The control rod system is designed to bring the reactor subcritical at a rate fast enough to prevent fuel damage; i.e.,
to prevent the MCPR from becoming less than the fuel cladding integrity safety limit. Analysis of the limiting power transients shows that the negative reactivity rates resulting from the scram with the average response to all drives as given in the above Specification, provide the required protection.
The numerical values assigned to the specified scram performance are based on the analysis of data from other BWR's with control rod drives the same as those on Peach Bottom.
The occurrence of scram times within the limits, but significantly longer than the average, should be viewed as an indication of a systematic problem with control rod drives especially if the number of drives exhibiting such scram times exceeds one control rod of a (5x5) twenty-five control array.
In the analytical treatment of the transients, which are assumed to scram on high neutron flux, 290 milliseconds are allowed between a neutron sensor reaching the scram point and the start of negative reactivity insertion. This is adequate and conservative when compared to the typical time delay of about-210 milliseconds estimated from scram test results. The 290 milliseconds used in the analyses consists of 90 milliseconds for sensor and circuit delay and 200 milliseconds to start of control rod motion. In addition the control rod drop accident has been analyzed in NEDO-10527 and its supplements 1 & 2 for the scram times given in Specification 3.3.C.
Measurement of the scram times with reactor steam dome pressure greater than or equal to 800 psig demonstrates acceptable scram times for the transients analyzed in UFSAR, Appendix K,Section VI and UFSAR Chapter 14.
Maximum scram insertion times occur at a reactor steam dome pressure of approximately 800 psig because of the competing effects of reactor steam dome pressure and stored accumulator energy. Therefore, demonstration of adequate scram times at reactor steam dome pressure greater than 800 psig ensures that the measured scram times will be within the specified limits at higher pressures. Limits are specified as a function of reactor .
pressure to account for the sensitivity of the scram insertion I times with pressure and to allow a range of pressures over which scram time testing can be performed. To ensure that scram time testing is performed within a reasonable time after fuel movement within the reactor pressure vessel or after a shutdown greater j than or equal to 120 days or longer, all control rods are l required to be tested before exceeding 40% of Rated Power i following the shutdown. In the event fuel movement is limited to selected core cells, only those control rods associated with the core cells affected by the fuel movements are required to be scram time tested. However, if the reactor remains shutdown for greater than or equal to 120 days, all control rods are required to be scram time tested.
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Unit 3 PBAPS 3.3 and 4.3 BASES (Cont'd)
Additional testing once per 120 days of a sample of the control rods is required to verify the continued performance of the scram i function during the cycle. A representative sample contains at !
least 10% of the control rods. For planned testing, the control l rods selected for the sample should be different for each test.
Data from inadvertent scrams should be used whenever possible to l avoid unnecessary testing at power, even if the control rods with l data may have been previously tested in a sample. The 120 day frequency is based on operating experience that has shown control rod scram times do not significantly change over an operating cycle.
When work that could affect the scram insertion time is performed on a control rod or the control rod drive system, testing must be done to demonstrate that each affected control rod retains adequate scram performance over the range of applicable reactor pressures from zero to the maximum permissible pressure. The scram testing must be performed once before declaring the control rod operable. The required scram time testing must demonstrate the affected control rod is still within the acceptable limits for reactor pressures less than 800 psig found in the Core Operating Limits Report.
Specific examples of work that could affect the scram times are (but are not limited to) the following: removal of any control rod drive for maintenance or modification; replacement of a control rod; and maintenance or modification of a scram solenoid pilot valve, scram valve, accumulator, isolation valve or check valve in the piping required for scram.
When work that could affect the scram insertion time is performed on a control rod or the control rod drive system, testing must be done to demonstrate each affected control rod is still within the limits with the reactor steam dome pressure greater than or equal to 800 psig. Where work has been performed at high reactor pressure, the requirements of 4.3.C.4 and 4.3.c.5 can be satisfied with one test. For a control rod affected by work performed while shut down; however, a zero pressure and high pressure test may be required. This testing ensures that, prior to withdrawing the control rod for continued operation, the control rod scram performance is acceptable for operating reactor pressure conditions. Alternatively, a control rod scram test during hydrostatic pressure testing could also satisfy both criteria.
Operability of the scraw discharge volume vent and drain valves is necessary for maintaining a reservoir to contain the water exhausted from all control rod drives during a scram.
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- Unit 3 PBAPS i
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Unit 3 l l
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LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REOUIREMENTS 3.5.J Local LHGR (Cont'd) 4.5.K Minimum Critical Power ;
Ratio (MCPR)
If at any time during operation it is !
determined by normal surveillance that limiting value for LHGR is being exceeded, action shall be initiated within one (1) 1. MCPR shall be checked daily hour to restore LHGR to wit'ein prascribed during reactor power operation limits. If the LHER is not returned to at ;t25% rated thermal power.
within prescribed limits within five (5) hours, reactor power shall be decreased 2. Except as provided in Spec-at a rate which would bring the reactor ification 3.5.K.3, the verifi-to the cold shutdown condition within cation of the applicability of 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> unless LHGR is returned to 3.5.K.2.a Operating Limits MCPR within limits during this period. Values shall be performed every -
Surveillance and corresponding action 120 operating days by scram shall continue until reactor operation time testing a representative is within the prescribed limits. sample of control rods and performing the following: '
3.5.K Minimum Critical Power Ratio (MCPR) a. The average scram time to the 20% insertion position
- 1. During power operation the MCPR for the shall be:
applicable incremental cycle core average exposure and for each type of fuel shall r ave s r 8 be equal to or greater than the value given in Specification 3.5.K.2 b. The average scram time to or 3.5.K.3, or MCPR(F), or the MCPR the 20% insertion position operating limit as determined by is determined as follows:
application of MCPR(P), whichever is greater. MCPR(F) and MCPR(P) are provided in the CORE OPERATING LIMITS REPORT. If at n any time during operation it is determined r ave - I Ni r i by normal surveillance that the limiting 1-1 value for MCPR is being exceeded, action shall be initiated within one (1) hour to n restore MCPR to within prescribed limits. E Ni If the MCPR is not returned to within prescribed limits within five (5) hours, i-1 reactor power shall be decreased at a rate which would bring the reactor to the cold where: n - number of shutdown condition within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> unless surveillance tests performed MCPR is returned to within limits during to date in the cycle.
this period. Surveillance and corres-ponding action shall continue until reactor operation is within the prescribed limits.
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