ML20035E735
| ML20035E735 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 04/13/1993 |
| From: | UNION ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20035E734 | List: |
| References | |
| NUDOCS 9304190167 | |
| Download: ML20035E735 (4) | |
Text
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REACTIVITY CONTROL SYSTEMS BASES MODERATOR TEMPTRATURE COEFFICIENT (Continued) r-fA/JEg7 A i
V The most negative MTC valuej equivalent to the most pohitive moderator density coefficient (MDC), was obtained by incrementally correcting the MDC used in the FSAR analyses to nominal operating conditions.O The:c c0rrection:
4^volved subtracting the incremental change da the MDC :::Ociated with : cerc
-eee.dition Of all rod: incerted (m0 t p0:4tive MDC) to ar :1' red: "ithdrara condition and, a corversi0n for the rate Of change Of modcrctor den;ity with
-tc ;cr ture et R*;TED THEPMAL "Oh'ER condition:. 751: s;1ue of the MO: w: then t
-transformed int ^ the '4-iting End of Life (EOL) MTC :1ut.
The 300 ppm l
surveillance limit MTC val.e represents a conservative value (with corrections for burnup and soluble borord at a core condition of 300 pom equilibrium baron concentration and is obtained byn :Fing there cor ectionE to the limiting EOL m
11TC value.
[
an a//swnce Ar Larnap ardn/alle leren csncenhafisn The Surveillant'[ Requirements for measurement of the MTC at the beginning i
and near 15e end of the fuel cycle are adequate to confirm that the MTC remains within its limits since this coefficient changes slowly due principally to the reduction in RCS boron concentration associated with fuel burnup.
3/4.1.1.4 MINIMUM TEMPERATURE FOR CRITICALITY This specificaticn ensures that the reactor will not be made critical with the Reactor Coolant System average temperature less than SSl*F.
This limitation is regoired to ensure:
(1) the moderator temperature coefficient is within its analyzed temperature range (2) the trip instrumentation is within its normal operating range, (3) the pressurizer is capable of being in an OPERABLE status with a steam bubble, and (4) the reactor vessel is above its minimum RT tempe rature.
NDT 3/4.1.2 BORATION SYSTEMS The Boration Systems ensure that negative reactivity control is available du ~ng each MODE of facility operation. The components required to perform this function include:
(1) borated water sources, (2) centrifugal charging pumps, i
(31 separate flow paths, (4) boric acid transfer pumps, and (5) an energency power supply from OPERABLE diesel generators.
With the RCS average temperature equal to or greater than 350*F a minimum of two boron injection flow paths are required to ensure single functional capability in the event an assumed failure renders one of the flow paths inoperable.
The Beration capability of either flow path is sufficient to provide a SHUTDOWN MARGIN from expected operati,9 conditions of 1.3% ak/k af ter xenon decay and cooldown to 200*F.
The maxiaum expected boration capability require-ment occurs' at EOL from full power equilibrium xenon conditions and requires 17,658 gallons of 7000 ppm borated water from the boric acid storage tanks or 83,745 gallons of 2350 ppm borated water from the RWST. With the RCS average temperature less than 350*F, only one bornn injection flow path is required.
CALLAWAY - UNIT 1 B 3/4 1-2 Amendment No. (5,58 9304190167 930413 ppg ADOCK 05000483 i
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i INSERT A I
These corrections involved: (1) a conversion of the MDC used-in the FSAR accident analyses to its equivalent MTC, based on the rate of change of. moderator density with temperature at RATED THERMAL POWER conditions, and (2) adding margin to i
this value to account for the largest difference in MTC.
observed between an EOL, all rods withdrawn, RATED THERMAL.
j POWER. condition and an envelope of those most adverse conditions of moderator temperature.and pressure, rods inserted to their insertion limits, axial power skewing, and~
t xenon concentration that can occur in. normal operation within Technical Specification limits and lead to a significantly more negative EO' MTC at RATED THERMAL POWER.
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These corrections transformed the MDC value used in the FSAR accident analyses into the lituiting End of Cycle Life (EOL)
MTC value.
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REACTIVITY CONTROL SYSTEMS l
t BASES MODERATOR TEMPERATURE COEFFICIENT (Continued) l The most negative MTC value, equivalent to the most positive moderator _
density coefficient (MDC), was obtained by incrementally correcting the MDC used in the FSAR analyses to nominal operating conditions. These corrections involved: (1) a conversion of the MDC used in the FSAR accident analyses to its equivalent MTC, based on the rate of change of moderator density with temperature at RATED THERMAL POWER conditions, and (2) adding margin to this value to account for the largest difference in MTC observed between an EOL, all rods withdrawn, RATED THERMAL POWER condition and an envelope of tisose most adverse conditions of moderator temperature and pressure, rods inserted to their insertion liuits, axial pcwer skewing, and xencn concentration that can occur in normal operation within Technical Specification limits and lead to a significantly more negative EOL MTC at RATED THERMAL POWER. These corrections transformed the MDC value used in the FSAR accident analyses into the limiting End of Cycle Life (EOL) MTC value. The 300 ppm surveillance limit MTC value represents a conservative value (with corrections for burner and soluble boron) at a core cordition of 300 ppm equilibrium boron concentration and is obtained by adding an allowance for burnup and soluble l
boron concentration changes to the limiting EOL MTC value.
The Surveillance Requirements for measurement of the MTC at the beginning and near the end of the fuel cycle are adequate to confirm that th, MTC remains within its limits since this coefficient changes slowly due principally to the reduction in RCS boron concentration associated with fuel burnup.
3/4.1.1 A MINIMUM TEMPERATURE FOR CRITICAL Tl l
r This specification ensures that the reactor will not be made critical with the Reactor Coolant System average temperature less than 551 F. This limitation is required to ensure: (1) the moderator temperature coefficient is within its analyzed temperature range, (2) the trip instrumentation is within its nonnal operating range, (3) the pressurizer is capable of being in an OPERABLE status with a steam bubble, and (4) the reactor vessel is above its minimum RT t
NDT emperature.
3/4.1.2 BORATION SYSTEMS t
The Boration Systems ensure that negative reactivity control is available during each MODE of facility operation. The components required to perform this function include: (1) borated water sources, (2) centrifugal charging pumps, (3) separate flow paths, (4) boric acid transfer pumps, and (5) an emergency power supply from i
OPERABLE diesel generators.
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0 CALLAWAY - l' NIT 1 B 3/4 1-2 Amendment No. 44,58
~,
With the RCS average temperature equal to or greater than 350 F, a minimum of two boron injection flow paths are required to ensure single functional capability in the event an assumed failure renders one of the flow paths inoperable. The Boration capability of either flow path is sufficient to provide a SHUTDOWN N!ARGIN from expected operating conditions of 1.3% Ak/k after xenon decay and cooldown to 200 F. The maximum expected boration capability requirement occurs at EOL from full power equilibrium xenon conditions and requires 17,658 gallons of 7000 ppm borated water from the boric acid storage tanks or 83,745 gallons of 2350 ppm borated water from the RWST. With the RCS average temperature less than 350 F, only one boron injection flow path is required.
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CALLAWAY - UNIT 1 B 3/4 1-2(a)
Amendment No. 4'A,58