ML20006E874
ML20006E874 | |
Person / Time | |
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Site: | Fort Calhoun ![]() |
Issue date: | 02/19/1990 |
From: | OMAHA PUBLIC POWER DISTRICT |
To: | |
Shared Package | |
ML20006E868 | List: |
References | |
NUDOCS 9002260468 | |
Download: ML20006E874 (11) | |
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2.0_ LIMITI30 CONDITIONS FOR OPERATION 2.5 ' Steam and Feedvater Systems- *
' Applicability Applies to the operating-status of the steam and feedvater systems.
Objective To define certain conditions'for the steam and feedvater system necessary to assure adequate decay heat removal.
Specifications The reactor coolant shall not be heated about 3000F unless the follevini; conditions are met:
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(1) Both auxiliary feedvater pumps are operable. One of the auxiliary feedvater pumps may be inoperable for 2h hours provided that the redundant component shall be tested to demonstrate operability.
f (2) A minimum of 55,000 gallons of water in the emergency feedvater storage tank and a backup vater supply to the ,
emergency feedvater storage tank from the Missouri River .!
( .. by the fire water system. I t .i (3'; All valves, interlocks and piping associated with the l above components required to function during accident j conditions are operable. Manual valves that could inter- -l'
'rup auxiliary feedvater flow to the . steam generators nhall be locked in the required position to ensure a flev path to the steam generators. ]4 (h) The main steam stop valves are' operable and capable of closing in four seconds or less under no-flow conditions. 'I Basis A reactor shutdown from power requires a removal of core de, cay ;
,jfP heat. Immediate decay heat removal. requirements are normally !
satisfied by the steam bypass to the condenser. Therefore, core decay heat can be continuously dissipated via the steam bypass to the condenser as long as feedvater to the steam !
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? generator is available. Normally, the capability to supply ,
feedvater to the steam generators is provided by operation '
o- of the turbine cycle feedvater system. In the unlikely event
- of complete loss of electrical power to the station, decay J heat removal is by steam discharge to the atmosphere via the main steam safety and atmospheric dump valves. Either auxi-
"' liary feedvater pump can supply sufficient feedvater for re-
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water in the emergency feedvater storage tank is the amount i
neeced for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of such operation. The tank can be re-nupplied with water from the fire protection system.(1)
Amenamen. No. 49 2-28 o ,
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N- 2. 0' ' LIMITING CONDITIONS FOR OPERATION i 2;5' - Steam and Feedvater Systems .(Continued)f t
~A closure time of h' seconds for the main steam stop valves is considered- 'I adequate and was selected as- being consistent with expected response :i entation as detailed in the steam line break-incident timefor{nt analysis. 2 ._ .
.r References-
- FSAR', Section 9.h.6. .'
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(2) FSAR', Section 10.3 [
(3) ' FSAR,'Section 14.12 P
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2o0 LIMITING CONDITIONS FOR OPERATION c h .2.5- Steam and Feedwater Systems !
Apolicability 4 Applies to the operating status of the steam and feedwater systems.
'Ob.iective
- To define certain conditions for the steam and feedwater system necessary to assure adequate decay heat removal.
Specifications (1) The reactor coolant shall not be heated abovt 300*F unless the 1. ;
following conditions are met: ]
W (a)- The motor driven auxilicry feedwater pump is operable.
(b) The integrity of the turbine driven auxiliary feedwater pump has been verified by observing the proper functioning of the
' steam turbine admission valves and the starting of-the pump. -
(c) A minimum 'of 55,000 gallons of water in the emergency feedwater storage tank and a backup water supply to the emergency feedwater. storage tank from the Missouri River by the fire
, water system shall be available.
(d) All valves, interlocks and piping associated with the above components required to function during accident conditions are operable. Manual valves that could interrupt auxiliary feedwater flow to the steam generators shall be locked in the required position to ensure a flow path to the steam generators. .
, 8 The main steam stop valves are operable and capable of closing (e) in four seconds or less under no-flow conditions. ,
(2). The turbine driven auxiliary feedwater pump shall be verified-operable within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after entry into mode 3.
(3) The reactor shall not be made critical unless both the motor driven and turbine driven auxiliary feedwater pumps are operable.
F Modification to minimum requirements (1) During modes 1 or 2, one auxiliary feedwater pump may be inoperable for up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, provided that the redundant component shall be tested to demonstrate operability. If the inoperable auxiliary feedwater pump is not restored within the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, then the unit shall be placed in mode.3 within 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> and the reactor coolant system cooled to less than 300*F within an additional 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
2-28 Amendment No. #
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- LIMITING CONDITIONS'FOR OPERATION
~ 2.0' 3'
2.5: Steam and Feedwater Systems 7 :
. -Modification-to minimum requirements (Continued)
(2) When the reactor coolant is above 300*F and not in mode 1 -or 2:
If both the motor driven and turbine driven auxiliary.feedwater
' (a) pumps are inoperable, then the-reactor coolant system shall be cooled to less than 300*F within 6 honrs.
(b) If-the turbine driven auxiliary feedwater pump cannot be verified operable within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after entering mode 3, then the reactor coolant system shall be cooled to less than 300*F within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
(c) After th'e turbine driven auxiliary feedwater pump is' verified operable per specification 2.5(2), one Auxiliary feedwater pump may be inoperable for up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, provided that the redundant component shall be tested to demonstrate operability. If the inoperable auxiliary feedwater pump is not restored within the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, then the reactor coolant system shall be cooled to less than 300*F within an additional 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
B1111 A reactor shutdown from power requires a removal of core decay heat.
Immediate decay heat removal requirements' are normally satisfied by the steam bypass to the condenser. Therefore, core decay heat can be continuously dissipated via the steam bypass to the condenser as long as feedwater.to the steam generator is available. Normally, the s
capability to supply feedwater to the steam generators is provided by operation of the. turbine cycle- feedwater system. In the unlikely event of complete ~ loss.of electrical power to_ the station, decay heat removal is by steam discharge to the atmosphere via the main steam safety and atmospheric dump: valves. . Either auxiliary feedwater pump can- supply sufficient feedwater-for removal of decay heat from the pl ant. The minimum amount of water in the emergency feedwater-storage tank is the amount needed for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of such operation. q tank can bere-suppliedwithwaterfromthefireprotectionsystem.]I-
-A closure time of 4 seconds for the main steam stop valves is :
considered adequate time and_was selected- as being consistent with .
expectedresponsetilgfginstrumentationasdetailedinthesteam line break analysis. , ;
Beferences (1) USAR, Section 9.4.6 I
(2) USAR, Section 10.3 (3) USAR, Section 14.12 2-29 Amendment No.
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F 3.0: SURVEILLANCE RE0VIREMENTS O
3.9 Auxiliary Feedwater System u/ - Apolicability
-Applies to periodic testing requirements of the turbine-driven and motor-driven auxiliary feedwater pumps.
- Objective To verify the operability of the auxiliary feedwater (AFW) system and its ability to respond properly when required.
Specifications (1) -The position of valves necessary to ensure auxiliary feedwater flow to the steam generators shall be verified by a monthly inspection. Anytime maintenance is performed on the auxiliary
.feedwater system which alters valve alignments, .an operator shall check that the AFW system valves are properly aligned, to ensure AFW ficw to the. steam generators, and a second operator shall independently verify proper valve alignment.
(2) The operability of the motor-driven auxiliary feedwater pump and the steam turbine-driven auxiliary feedwater pump shall be confirmed at least monthly.
(3) The operability of auxiliary feeduater pumps' steam generator level regulating valves HCV-1107A, HCV-11078, HCV-1108A, HCV-1108B, and auxiliary feedwater cross-tie valve'HCV-1384 shall'be confirmed at least every three months.
(4)' The capabilities of the motor-driven and turbine-driven auxiliary 1 feedwater pumps shall be verified by using local pressure indicators .and flow indicators in- the control room. The dis-charge pressure will be verified to be 40 psig above the steam generator pressure at rated steam flow.
(5) Following cold shutdogn and prior to raising the reactor coolant l temperature above 300 F, the motor-driven auxiliary feedwater pump shall be tested to verify the normal flow path for auxiliary .feedwater to the steam generators.
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(6) At least once per 18 months during shutdown by:
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- a. Verifying that each automatic valve in the flow path actuates to its correct position upon receipt of each auxiliary feedwater actuation test signal.
- b. Verifying that each auxiliary feedwater pump starts as designed automatically upon receipt of each auxiliary
'( feedwater actuation test signal.
3-62 Amendment No. 49. E4, 90 a
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(PRESENT) oc 0-3.0 SURVEILLANCE REOUIREMENTS i:. -
3.9 Auxiliary Feedwater System (Continued) ,
Basis-
' The -valve position verifications performed monthly and following auxiliary feedwater system maintenance will confirm the avail-ability of an auxiliary feedwater flow ~ path to the steam generators.
The testing of the auxiliary feedwater pumps every month and after cold-shutdowns will ~ verify their operability by recirculating water
- to the emergency feedwater storage tank.
Operating the regulating valves (HCV-1107A, HCV-11078, HCV-1108A and HCV-1108B) one at a time every three months and.after cold shutdowns will. confirm a flow path to the steam generators and operability of the valves.
Proper functioning-of the steam turbine admission valve and starting'
' of the feedwater pump will demonstrate the integrity of the- steam.
-driven pump. Verification of correct operation will be made both from instrumentation within the main control room and direct visual observation of the pumps.
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The operability.of the auxiliary feedwater system ensures ghat the
' reactor coolant system can be cooled down to less than 350 F from-normal operating conditions in the event of a-total loss of off-site power.
References (1) FEAR,;Section 9.4~.
-(2) Technic &l . Specification 2.5 i
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3-62a Amendment flo. 69, E4, 90 h
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.3.0 SURVEILLANCE RE0VIREMENTS 3.9 Auxiliary Feedwater System Apolicability Applies to periodic testing requirements of the turbine driven and motor driven auxiliary feedwater pumps.
Obiective To verify the operability of the auxiliary feedwater (AFW) system and its 1 ability to respond properly when required.
Specifications (1) The position of valves necessary to ensure auxiliary feedwater flow to the steam generators shall be verified by a monthly inspection.
Anytime maintenance-is performed on the auxiliary feedwater system which alters valve alignments, an operator shall-check that the AFW system valves are- properly aligned, to ensure AFW flow to' the steam generators, and a second operator shall independently verify proper valve . alignment.
(2) During modes 1 and 2, the operability of the motor driven auxiliary feedwater pump and the-steam turbine driven auxiliary feedwater pump .
shall be confirmed at least monthly by using local pressure indicators and flow indicators in the control room. The discharge pressure will be verified to be at least 40 psig above the steam generator pressure.
-(3) The operability of' auxiliary feedwater pumps' steam generator level regulating valves HCV-1107A HCV-1107B, HCV-1108A,,, HCV-11088, and auxiliary feedwater cross-tie valve HCV-1384 shall be confirmed at <
least every three months.
(4) Following cold shutdown, the auxiliary feedwater system operability shall be demonstrated as follows:
(a)- Prior to raising reactor coolant temperature above 300*F, the operability of the motor driven pump.and normal flow path for auxiliary feedwater to the steam generators shall be verified.
(b) Prior to raising reactor coolant temperature above 300'F, the integrity of the turbine driven pump shall be verified by observing the proper functioning of the steam turbine admission valves and the starting of the pump.
(c) Within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after achieving mode 3, but prior to entering mode 2, the operability of the turbine driven pump shall be verified as in 3.9(2).
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i L3.0 SURVEILLA'CE N REQUIREMENTS E 3.9 Auxiliary Feedwater System Speci fications - J
-(5). At least once per plant operating ' cycle during shutdown: ;
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- a. Verify that each automatic valve in the flow path actuates to its ;
correct position upon-receipt of each auxiliary feedwater L actuation test signal, b.- Verify that the motor driven feedwater pump starts and the turbine driven pump steam ' admission valves open as designed !
t automatically upon receipt of each auxiliary feedwater actuation l test signal.
Basis The valve position verifications performed monthly and following auxiliary feedwater maintenance will confirm the availability of an auxiliary feedwater flowpath to the steam generators.
The testing of the auxiliary feedwater pumps every menth and after cold shutdowns will verify their-operability by recirculating water to the emergency feedwater storage tank.
Operating the regulating valves -(HCV-1107A, HCV-Il078, HCV-1108A, and HCV-11088) one at a time every three months and after cold shutdowns will -
confirm a flow path to the steam generators and operability of the valves.
Proper functioning of the steam turbine admission valve and starting of the feedwater pump will demonstrate the integrity of the steam driven pump.-
Verification of correct operation will be made both from instrumentation within~ the main control room: and direct visual observation of' the pumps. .
The operability of the auxiliary feedwater system ensures that the rector coolant system can be cooled to less than 350*F from normal. operating conditions in the event of a total loss of off-site power.
. References (1)- USAR, Section 9;4 (2) Technical Specification 2.5 3-62a Amendment No. fE,EA,9E
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.- , . Discussion <
- Justification and No Significant Hazards Consideration The proposed change _ to-Technical Specification Section 2.5(1), Page 2-28 is requested to allow performance of a functional test of the steam driven Auxiliary Feedwater (AFW) Pump (FW-10) prior to achieving criticality and to correct a typographical error. The present temperature of 300*F will not provide enough steam to allow for a normal operability test. ,
The design basis of the AFW system is to remove decay heat after a reactor shutdown from power operation in the unlikely event of a complete loss of electrical power to the station. In addition, either Auxiliary Feedwater Pump
-can provide sufficient feedwater for removal of decay heat.
The current Technical Specifications allow one auxiliary feedwater pump to be inoperable for_24 hours after going above 300*F. In theory this would allow enough time for the plant to heat-up to the point that a normal operability test of-the pump could be run. Typically, however, due to steam generator soaks the period .it takes to heat up the plant so that this test can be run is
_ greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. This issue has been solved at one other plant (see
. References 2 and 3) by requiring that the steam driven pump be operable " prior to making the reactor critical." This allows heat up of the plant to the point where steam can be produced to perform a normal operability test using non-nuclear heat.
No Significant Hazards Consideration '
This proposed amendment does not involve a significant hazards consideration because'the operation of Fort Calhoun Station in accordance with this amendment would not:
- 1. Involve a significant increase in the probability or consequences of ,
an accident previously evaluated. Accidents have been analyzed assuming the auxiliary feedwater system is available to provide ;
removal of decay heat produced during the eight hours after a reactor trip concurrent with a loss of main feedwater. The current specification allows either the electric or steam-driven auxiliary feedwater pump to be inoperable when the reactor coolant temperature is above 300'F for up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The proposed change clarifies the integrity requirements during heatup for the turbine driven auxiliary feedwater pump that were previously contained in Section 3.9 (Basis) and adds requirements and time limits for testing of the turbine driven pump after entering mode 3 and prior to entering mode 2. This was done to ensure that testing to determine operability is performed at the earliest possible opportunity after plant conditions permit.
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The specification also clarifies actions:for equipment failures that-p should be taken that' previously were not contained in the j U -specification. Section 3.9 was modified to be-consistent with the new requirements _in Section 2.5. ,
- 2. Create th'e. possibility of.a new or different kind of accident-from any previously evaluated. The proposed change does not physically alter the configuration of the plant and no new or different mode of operation has been implemented. Therefore, the possibility of an l accident or malfunction of a new or different type than any previously.
evaluated in the safety analysis report is not created.
- 3. Involve a significant reduction in a margin:of safety. Decay heat l removal is still assured to the same degree .as prior to this change because the operability requirements of the Auxiliary feedwater System have been clarified and strengthened. The intent of the specification has not been changed, and thus the basis for the safety analysis is maintained. ~ As a result the margin of safety is.not reduced. ,
Therefore,. based on the above consideration Omaha Public Power District has determined that the change does not involve a significant_ hazards consideration, l
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