ML20217D796
| ML20217D796 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 10/12/1999 |
| From: | COMMONWEALTH EDISON CO. |
| To: | |
| Shared Package | |
| ML20217D795 | List: |
| References | |
| NUDOCS 9910180145 | |
| Download: ML20217D796 (10) | |
Text
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' ATTACHMENT B ;
l Proposed Change to Technical Specifications ,
Quad Cities Nuclear Power Station - Units 1 and 2 1
, (Page 1 of 1) i 1
MARKED-UP TS PAGES FOR PROPOSED CHANGES l
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I 9910180145 991012 PDR ADOCK 05000254 i P PDR l I
4 LSSS 2.2 TABLE 2.2.A-1 (Continued)
REACTOR PROTECTION SYSTEM INSTRUMENTATION SETPOINTS Functional Unit Trio Setooint
- 7. Drywell Pressure - High s2.5 psig
- 8. Scram Discharge Volume Water Level - High: 540 gallons
- 9. Turbine Stop Valve - Closure $10% closed
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- 10. Tri! : ::0 0:n;;;: ^" "::::r: ' : c.
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- 11. Turbine Control Valve Fast Closure 2460 psig EHC fluid pressure I
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- 12. Turbine Condenser Vacuum - Low 221 inches Hg vacuum f
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- 13. Reactor Mode Switch Shutdown Position NA
- 14. Manual Scram NA I
QUAD CITIES - UNITS 1 & 2 25 Amendment Nos. 171 & 167 1
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LSSS B 2.2 BASES i
-7. Drvwell Pressure - Hioh High pressure in the drywell could indicate a break in the primary pressure boundary systems or a loss of drywell cooling. Therefore, pressure sensing instrumentation is provided as a backup to the water level instrumentation. The reactor is scrammed on high pressure in order to minimize the possibility of fue! damage and reduce the amount of energy being added to the coolant and the primary containment. The' scram setting was selected as low as possible without causing spurious scrams.
- 8. Scram Discharoe Volume Water Level- Hioh The control rod drive scram system is designed so that all of the water which is discharged from the reactor by a scram can be accommodated in the discharge piping. A part of this system is an individual instrument volume for each of the scram discharge volumes. These two instrument volumes and their piping can hold in excess of 90 gallons of water and are the low point in the piping. No credit was taken for the instrument volumes in the design of the discharge piping relative to the amount of water which must be accommodated during a scram. During normal operations, the scram discharge volumes are empty; however, should either scram discharge volume accumulate water, the water discharged to the piping from the reactor during a scram may not be accommodated which could result in slow scram times or partial or no control rod insertion.
To preclude this occurrence, level switches have been installed in both instrument volumes which will alarm and scram the reactor while sufficient volume remains to accommodate the discharged }
water. Diverse level sensing methods have been incorporated into the design and logic of the system to prevent common mode failure. The setting for this anticipatory scram signal has been chosen on the basis of providing sufficient volume remaining to accommodate a scram, even with 5 gpm leakage per drive into the scram discharge volume. As indiccted above, there is sufficient volume in the piping to accommodate the scram without impairment of the scram times or the amount of insertion of the control rods.
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- 9. Turbine Stoo Valve - Closure j 1
The turbine stop valve closure scram setting anticipates the pressure, neutron flux, and heat flux
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increase that could result from rapid closure of the turbine stop valves. With a scram setting of
.10% of valve closure from full open, the resultant increase in surface heat flux is limited such that MCPR remains above the fuel cladding integrity Safety Limit, even durinq the worst case transient that assumes the rbine bypass fails to operate.
Dele 4ed
- 10. T d :..; O Cc-t r! On n em- 1 -
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}T tu ine r!fiC ntro yst ope tes ng 'h essur oil. T re ar ever oin in is s te her ai s of pre ure uld suit af clos of t turbi con ol ves h fas clo re o the t ine ontrol alv is n t pro cted- the rbine tro alv fas QUAD CITIES - UNITS 1 & 2 B29 Amendment Nos. 11 & W
LSSS B 2.2 4- BASES Iclosure scram sinc ilure o e oil yste would not result in the fast closure solenoid va es being actuated. or a tu e co va fast sure, he core ould be pr cted by e APRM and reactor gh pres e ser s. H ever,t provi the se e margins provide or the genera load re' son o st clo re of t turbi contro alves, a a m has en added th actor pr ction em w ch sen s failu of con i oil press a to the rbine co of s stem. s scra nticipa the pr sure t nsient ich would acaus y immi nt control valve osure an osults i sector utdow before ny signific incre in neutr flux o rs. The naient ponse i ery si lar to at resultin rom th urbine c trol valve st closure s m. Ho ver, sin the co rol vai s will not s rt to ci e until t fluid pres re is appro ately 6 psig, t scram low t ine EHC c trol oil ressure o urs well o tu ne contr valve clo re begi . The cram settin s high nough to ovide th' ec ary Qcipatory function d low e ugh t minimize the umbe of spurio scrams.
- 11. Turbine Control Valve Fast Closure The turbine contrul valve fast closure scram is provided to anticipate the rapid increase in pressure and neutron flux resulting from fast closure of the turbine control valves due to a load rejection and subsequent failure of the bypass valves; i.e., MCPR remains above the fuel cladding integrity Safety Limit for this transient. For the load rejection without bypass transient from 100% power, the peak heat flux (and therefore LHGR) increases on the crder of 15% which provides a wide margin to the value corresponding to 1% plastic strain of the cladding.
The scram setting based on EHC fluid pressure was developed to ensure that the pressure switch is actuated prior to the closure of the turbine control valves (at approximately 400 psig EHC fluid pressure), yet assure that the system is not actuated unnecessarily due to EHC system pressure transients which may cause EHC system pressure to momentarily decrease.
- 12. Turbine Condenser Vacuum - Low Loss of condenser vacuum occurs when the condenser can no longer handle the heat input. Loss of condenser vacuum initiates a closure of the turbine stop valves and turbine bypass valves which eliminates the heat input to the condenser. Closure of the turbine stop and bypass valves causes a pressure transient, neutron flux rise and an increase in surface heat flux. To prevent the fuel cladding integrity Safety Limit from being exceeded if this occurs, a reactor scram occurs on turbine stop valve closure. The turbine stop valve closure scram function alone is aderiuate to prevent the fuel cladding integrity Safety Limit from being exceeded, in the event of a turbine trip transient with bypass closure. The condenser low vacuum scram is anticipatory to the stop valve closure scram and causes a scram before the stop valves (and bypass valves) are closed and thus, the resulting transient is less severe.
A QUAD CITIES - UNITS 1 & 2 B 2-10 Amendment Nos. 171 !. W
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RPS B 3/4.1 BASES The IRM system provides protection against excessive power levels and short reactor periods in the startup and intermediate power ranges (reference SAR Sections 7.4.4.2 and 7.4.4.3).
In the' power range, the APRM system provides required protection (reference SAR Section 7.4.5.7.). Thus, the IRM system is not required (and is automatically bypassed) in OPERATIONAL MODE 1, the APRMs cover only the intermediate and power range; and the IRMs provide adequate coverage in the startup and intermediate range. The IRM inoperative function ensures that the j instrument CHANNEL fails in the tripped condition upon loss of detector voltage.
Three APRM instrument CHANNEL (s) are provided for each TRIP SYSTEM APRM CHANNEL (s) #1 and #3 operate contacts in one logic path and APRM CHANNEL (s) #2 and #3 operate contacts in ,
the other logic path of the TRIP SYSTEM. APRM CHANNEL (s) #.1 #5 and #6 are arranged similarly
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in the other TRIP SYSTEM's duallogic paths. Each TRIP SYSTEM has one more APRM than is 1 necessary to meet the minimum number required per CHANNEL. This allows the bypassing of one )
APRM per TRIP SYSTEM for maintenance, testing, or calibration. Additional IRM CHANNEL (s) have l also been provided to allow for bypassing of one such CHANNEL.
A reactor mode switch is provided which actuates or bypasses the various scram functions appropriate to the particular plant operating status (reference SAR Section 7.7.1.2). A bypass in the Refuel or Startup/ Hot Standby operational modes is provided for the turbine condenser low vacuum scram and main steam line isolation valve closure scrams for flexibility during startup and to allow repairs to be made to the turbine condenser. While this bypass is in effect, protection is provided against pressure or flux increases by the high-pressure scram and APRM 15% scram, respectively, which are effective in Startup/ Hot Standby.
The manual scram function is available in OPERATIONAL MODE (s) 1 through 5, thus providing for a manual means of rapidly inserting control rods whenever fuel is in the reactor.
The turbine stop valve closure scramb '""*e Eur -m.,,a ga igg .,.g 7_.c ::Dand the turbine control valve fast closure scram occur by design on turbine first stage pressure which is normally equivalent to -45% RATED THERMAL POWER. However, since this is dependent on bypass valve position, the conservative reactor power is used to dr . ermine applicability.
Surveillance requirements for the reactor protection system are selected in order to demonstrate proper function and operability. The surveillance intervals are determined in many different ways, such as,1) operating experience, 2) good engineering judgement, 3) reliability analyses, or 4) other analyses that are found acceptable to the NRC. The performance of the specified surveillances at the specified frequencies provides assurance that the protective functions associated with each CHANNEL can be completed as assumed in the safety analyses. A surveillance interval of " prior to startup" assures that these functions are available to perform their safety functions during control QUAD CITIES - UNITS 1 &2 B 3/4.1 2 Amendment Nos.183; 180
ATTACHMENT C l Proposed Change to Technical Specifications l . Quad Cities Nuclear Power Station - Units 1 and 2
, (Page 1 of 2) l lNFORMATION SUPPORTING NO SIGNIFICANT HAZARDS FINDING l Comed has evaluated this proposed amendment and determined that it involves no significant hazards consideration. According to 10 CFR 50.92(c), a proposed amendment _
to an operating license involves a no significant hazards consideration if operation of the ]
facility in accordance with the proposed amendment would not: '
Involve a significant h. crease in the probability of occurrence or consequences of an accident previously evaluated, Create the possibility of a new or different kind of accident from any previously analyzed; or involve a significant reduction in a margin of safety.
Comed is proposing to remove the existing turbine electro-hydraulic control (EHC) control oil low pressure scram function specified in Technical Specifications (TS) Section 3/4.1.A,
" Reactor Protection System," cnd the corresponding Safety System Setting in TS 2.2 !
" Limiting Safety System Settings."
The determination that the criteria set forth in 10 CFR 50.92 is met for this amendment l request is indicated below:
Does the change involve a significant increaa in the probability of occurrence or ,
consequences of an accident previously evaluated?
The proposed change removes the Turbine EHC Control Oil Pressure-Low scram function and the associated Limiting Safety System Setting (LSSS). The purpose of the Turbine EHC Control Oil Pressure scram is to anticipate the pressure transient which would be ,
caused by imminent control valve closure on loss of control oil pressure. This function does not serve as an initiator for any accidents evaluated in Chapter 15 of the Updated Final Safety Analysis Report (UFSAR). In addition, this trip function is not credited in any design basis event and is functionally redundant to the Turbine Control Valve Fast Closure RPS trip function during a postulated loss of EHC control oi; event. The Turbine Control Valve Fast Closure will initiate a scram on a loss of control oil event coincident with turbine control valve closure.
Therefore, this proposed amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated.
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ATTACHMENT C Proposed Change to Technical Specifications Quad Cities Nuclear Power Station - Units 1 and 2 (Page 2 of 2) i Does the change create the possibility of a new or different kind of accident from i any accident previously evaluated?
l The removal of this function does not represent a change in operating parameters or introduce a new mode of operation. The pressure switches associated with the Turbine Control Valve Fast Closure function provide equivalent protection from a loss of EHC oil I event. For this reason, the change does not create the possibility of a new or different kind of accident from any accident previously evaluated.
Does the change involve a significant reduction in a margin of safety?
Operation under the proposed amendment will not change any plant operation parameters, nor any protective system actuation setpoints other than removal of the Turbine EHC Control Oil Pressure-Low scram function. The scram function associated with the Turbine Control Valve Fast Closure provides equivalent protection for events I involving fast turbine control valve closure including the loss of EHC control oil pressure.
For this reason, eliminating the EHC Control Oil Pressure-Low scram function, which is redundant to other protective instrumentation, does not reduce the margin of safety.
Therefore, based upon the above evaluation, Comed has concluded that these changes involve no significant hazards consideration.
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L _, ATTACHMENT D Proposed Change to Technical Specifications Quad Cities Nuclear Power Station - Units 1 and 2
, , (Page 1 of 1)
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INFORMATION SUPPORTING AN ENVIRONMENTAL ASSESSMENT l
1 Comed has evaluated this proposed operating license amendment request against the
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criteria for identification of licensing and regulatory actions requiring environmental assessment in accordance with 10 CFR 51.21. Comed has determined that this i'
- proposed license amendment request meets the criteria for a categorical exclusion set forth in 10 CFR 51.22(c)(9) and as such, has determined that no irreversible consequences exist in accordance with 10 CFR 50.92(b). This determination is based on l the fact that this change is being proposed as an amendment to a license issued pursuant 1 to 10 CFR 50, that changes a requirement with respect to installation or use of a facility l component located within the restricted area, as defined in 10 CFR 20, or that changes an i inspection or a surveillance requirement, and the amendment meets the followhg specific l criteria
(i) the amendment involves no significant hazards consideration.
As demonstrated in Attachment C, this proposed amendment does not involve a significant hazards consideration. i (ii) there is no significant change in the types or significant increase in the amounts of any effluent that may be released offsite.
As documented in Attachment A, there will be no change in the types or significant increase in the amounts of any effluents released offsite.
(iii) there is no significant increase in individual or cumulative occupational radiation exposure.
' There will be no change in the level of controls or methodology used for processing of radioactive effluents or handling of solid radioactive waste, nor will the proposal result in any change in the normal radiation levele within the plant.
Therefore, there will be no increase in individual or cumulative occupational radiation exposure resulting from this change. ]
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