ML20053A654
| ML20053A654 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 05/24/1982 |
| From: | COMMONWEALTH EDISON CO. |
| To: | |
| Shared Package | |
| ML20053A652 | List: |
| References | |
| NUDOCS 8205270082 | |
| Download: ML20053A654 (7) | |
Text
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CONTAINMENT SYSTEMS
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3/4.6.6 PRIMARY CONTAINMENT ATMOSPHERE CONTROL
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DRYWELL AND SUPPRESSION CHAMBER HYDROGEN RECOMBINER SYSTEMS g
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LIMITING CONDITION FOR OPERATION 4
0 3.6.6.1 Two independent drywell and suppression chamber hydrogen recombiner systems shall be OPERABLE.
APPLICABILITY:
OPERATIONAL CONDITIONS 1 and 2.
ACTION:
With one drywell and/or suppression chamber hydrogen recombiner system inoperable, restore the inoperable system to OPERABLE status within 30 days or be in at least HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
SURVEILLANCE REQUIREMENTS 4.6.6.1 Each drywell and suppression chamber hydrogen recombiner system shall be demonstrated OPERABLE:
j a.
At least once per 92 days by cycling each flow control valve and 1
recirculation valve through at least one complete cycle of full travel.
b.
At least once per 6 months by verifying, during a recombiner system e
functional test:
(
1.
That the heaters are OPERABLE by determining that the current in each phase differs by less than or equal to 5% from the other phases and is within 5% of the value observed in the original acceptance test, corrected for line voltage differences.
2.
That the reaction chamber gas temperature increases to 1200 IF within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.
2cj c.
At least once per 18 months by:
1.
Performing a CHANNEL CALIBRATION of all recombiner operating instrumentation and control circuits.
2.
Verifying the integrity of all heater electrical circuits by performing a resistance to ground test within 30 minutes following the above required functional test.
The resistance to ground for j
any heater phase shall be greater than or equal to 100,000 ohms.
l d.
By measuring the leakage rate:
1.
As a part of the overall integrated leakage rate test required by Specification 3.6.1.2, or l
2.
By measuring the leakage rate of the system outside of the containment isolation valves at P, 39.6 psig, on the schedule 3
i required by Specification 4.6.1.2 and including the measured
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leakage as a part of the leakage determined in accordance with l (
Specification 4.6.1.2.
LA SALLE - UNIT 1 3/4 6-43 l
820527008 7 L
May 24, 1982 LaSalle County Station Unit 1 l
Tech Spec Change Request NPF-ll/82-2 i
Subject:
MSIV closure scram setpoint change.
References:
1.)
Letter H. R. Pe f fer ( G.E. ) to G. R.
Crane (CECO) dated 3/15/82 LaSalle County Station Units 1 & 2 i
" Technical Specifications on MSIV closure scram.'g
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(Enclosed) 2.)
FSAR Sections: 7.2.2.2 MSIV line closure, 5.4.5 Main Steam Line Isolation System 15.2.4.,
Inadvertent MSIV' Closure accident analysis, Table 14.2-122 MSIV start up test.
Background:
The above proposed Technical Specification change has been requested as a result of the inability to meet the Technical Specification setpoint as determined during final preoperational testing.
Discussion:
The MSIV closure scram setpoint of 6% closure trip /7%
closure allowable cannot be met for the 6% trip setpoint due to the design of the limit switch travel and the mounting design on the valve for separation criteria.
The station proposes to change the scram setpoints to 8%
closure trip and 12% closure allowable.
The two values in the Technical Specifications are given to account for drift, accuracy and calibration.
The basis for this change is contained in a letter from General Electric (Reference 1) which states that a reanalysis of the MSIV closure transient position scram with an 85% analytical MSIV open position scram initiation (equivalent to 88% open or 12%
closed Tech Spec value to account for drif t and inaccuracies) versus the current 90% analytical value results in no effect on the operating limit MCPR and only a slight 4 psig increase in vessel pressure (1203 vs. 1199 psig).
This will however, have some ef fect on the peak vessel pressure response in the MSIV closure start-up test.
Commonwealth Edison's Nuclear Fuel Services Department has concurred in the revised setpoints based on the General Electric Analysis.
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Conclusion:==
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T Commonwealth Edison finds n.o~unreviewed safety questions
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-involved.
The ma rgin of safety as de fined 1'n-the Technical
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Speci fica tionti is slig'ritly reduced as a -result of thef longer time' to scram, however, the analyzed tr,ansien.t' has negligible'effect on the' 4 w MCPR.
Also, the MSIV closure position scram for LaSal~1e County Unit 1 is one of the least limiting of the mpderate frequency transients
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as analyzed in the FSAR,,.f ar below the Load Reject with. Bypass and the Feedwater Controller' Failure.
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& /2 c-9 GENER AL h ELECTRIO suctein pOwen SYSTEMS DIVISION GENERAL ELECTRIC OOMPANY,175 CURTNER AVE., SAN wCSE CALIFORNIA 95125 MC 391, (408) ~S25-3798 LS-2203 March 15, 1982 Mr. G. R. Crane Commonwealth Edison Company One First National Plaza Chicago, IL 60690 Daar Mr. Crane:
SUBJECT:
LASALLE COUNTY STATION UNITS 1 & 2 TECH!uCAL SPECIFICATIONS ON MSIV CLOSURE SCRAM
Reference:
Letter, (LSC-2575) G. R. Crane to H. R. Peffer, dated 2/11/82, same subject In response to your reference request, we have completed an evaluation to determine the acceptability of lowering the subject Tech Spec from a nominal setpoint of 94% open (corresponding to an analytical / design limit of 90% open) to a lower value.
From the results of the evaluation, it has been determined that the analytical / design limit can be lowered to 85% open with no significant impact on the OLCPR.
Therefore, we recommend
. changes to the MSIV closure scram Tech Specs as indicated in the attached.
These changes should not only satisfy your requested needs, but also provide you added flexibility.
If you have any questions regarding the attached, please feel free to call us.
Very truly yours
% QP H. R. Peffer, oject Manager LaSalle Count Station Units 1 & 2 HRP:hmc/0031514
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Attachme'nt cc:
D. C. Haan P. P <Kavanagh B.'R.Shelton/
R. E. Spencer T. E. Watts DBL /PT/CTK
- mys QUESTION.
Determine the feasibility of changing the MSIV scram tech. spec. set-points from 94% open to less than 92% open.
RESPONSE
An analysis was performed to first determine how the required operating limit CPR for LaSalle would be affected if the MSIV direct scram signal is changed from a nominal setpoint of 94% opening to a less than 92%
opening position (corresponds to an analytical limit of 90% and 88%
respectively).
For this purpose, an ODYN analysis was performed on a MSIV position scram event (the only event which takes credit for direct MSIV scram in the LaSalle FSAR report).
Results of the analysis con-i firmed that even with the conservative analytical limit scram position of 85% open, the current LaSalle OL CPRs are still unaffected.
The required operating limit CPR values for the main steam line position scram at 85% position are:
Option A*
( 1.18 Option B*
( 1.10 The assumed scram signal was not initiated until 0.45 seconds following the beginning of the MSIV transient.
As a comparison to the other more limiting transients given in the OL CPR map, the delta CPR of the MSIV direct scram transient is significantly less than that of both l
LR W/ bypass (0.07) and FWCF (0.11).
The peak vessel pressure of 1203 psig in this MSIV event is also bounded by the 1270 psig derived for the overpressure protection report. Based on the above analysis, the follow-ing bases were established for the tech. spec.:
Nominal 92%
Tech. Spec.hlwe)88%
Analytir:al Limit 85%
Drift 4%
Accuracy 2%
Calibration 2%
Discussions with field engineers, who have been closely associated with setting up and adjusting the MSIV position switches for scram, confirmed that, with real effort, the switches can be set with i 1/2% band around the nominal trip setpoint.
I It should also be noted that the drift, accuracy and calibration numbers l
l given above all two sigma.
Includes adjustment factors as specified in the NRC SER on ODYN, NEDO-24154.
NS: hf r/C031"1 3/11/82
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LASALLE The tech. spec. and nominal setpoints are determined as follows:
2 + Calibration 2 Tech. Spec. = Analytical limit +7 Accuracy Nominal
= Tech. Spec. + Drift The band, around the nominal trip setpoint, which we consider acceptable (no readjustment required) is -1% in the Tech. Spec. direction (91%
minimum) and whatever will provide adequate assurance that the switches will reset and not cause spurious scrams in the plus direction toward 100% open.
The position switches do not drift like an instrument setpoint drifts due to the changes in the physical characteristics.
The position switch setpoints stay put unless bolts loosen up which might cause a gross shift. The problem is rather one of measuring valve position when the switch trips.
The 4% drift allowance is considered adequate to cover this measurement problem.
The preceding information is background supporting information to the requested change to the Tech. Spec. Ta ble 2.2.1-1.
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NS:hjr/C03115-2 3/11/82
T3CLE 2.2.1-1 g
REACTOR PROTECTION SYSTEM INSTRUMENTATION SETPOINTS y;
ALLOWABLE FUNCTIONAL UNIT TRIP SETPOINT VALUES
{:
1.
Intermediate Range Monitor, Neutron Flux-High 5 120 divisions of 1 122 divisions Si full scale of full scale Q
2.
Average Power Range Monitor:
a.
Neutron Flux-Hign, Setdown 1 15% of RATED THERMAL POWER 5 20% of RATED THERMAL POWER b.
Flow Biased Simulated Thermal Power - Upscale
- 1) Flow Biased 5 0.66W + 51% with a 1 0.66W + 54% with a maximum of maximum of
- 2) High Flow Clamped 5 113.5% of RATED 5 115.5% of RATED THERMAL POWER THERMAL POWER c.
Fixed Neutron Flux-High 5 118% of RATED THERMAL POWER 1 120% of RATED THERMAL POWER 3.
Reactor Vessel Steam Dome Pressure - High 1 1043 psig i 1063 psig s,
I 4.
Reactor Vessel Water Level - Low, Level 3 1 12.5 inches above instrument 1 11.0 inches zero*
above instrument zero*
O 12 h
5 @ closed i T% closed 5.
Main Steam Line Isolation Valve - Closure 6.
Main Steam Line Radiation - High 1 3.0 x full power background 5 3.6 x full power background 7.
Primary Containment Pressure - High 5 1.69 psig 1 1.89 psig 8.
Scram Discharge Volume Water Level - High 5 767' 5%"
$ 767' 5\\"
9.
Turbine Stop Valve - Closure 1 5% closed 5 7% closed 10.
Turbine Control Valve Fast Closure, Trip 011 Pressure - Low 1 500 psig 1 414 psig 11.
Reactor Mcde Switch Shutdown Position NA NA 12.
Manual Scram NA NA aSee Bases Figure B 3/4 3-1.
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