ML19322B519
| ML19322B519 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 05/01/1974 |
| From: | Thies A DUKE POWER CO. |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 7912040550 | |
| Download: ML19322B519 (3) | |
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DUKE POWER COMPANY Powrn Burt.orwo 4aa Sourn Cauncu SrazzT, CHARIDTTz, N. C. 28201 A. c. nu zs se..on v cc Passaogar P. o. Box 2178 paoover.on a.o 7 4.s-.ss.o.
May 1, 1974
&i ry G
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k,(3 Mr. Angelo Giambusso G
Deputy Director for Reactor Projects l
el MAY9 1974 "@F,,
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Directorate of Licensing Office of Regulation U. S. Atomic Energy Commission
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Washington, D. C.
20545 b
ikin.3 h Re: Oconee Nuclear Station
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, g Docket No. 50-269, -270, -287
Dear Mr. Giambusso:
Please find attached a description of the errors assumed by the safety analyses to determine the Oconee Reactor Protective System trip setpoints.
This information is submitted in response to an informal request by members of your staff.
Very truly yours,
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-- MAf e 3 1974
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1.-
High Flu # Trip.
Tha pow r 1sval indientid by tha nzutrtn flux is assumed to have 'a maximum error of -6.5% of rated power. All accident an,alysis cal-culations assume that the high flux trip will not actuate until the setpoint has. been excee' ed by 6.5% of rateJpower.
The components of this total error d
are:
2.0% heat balance error 4.0% neutron power measurement error
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0.5% setpoint error 6.5% total power measurement error 2.
High RC Pressure Trip.
The total RC pressure measurement error is assumed to be -30 psi.
It is further assumed that the RC pressure at the hot leg tap is 30 psi less than the pressure at the core outlet. All accident analysis calculations assume that the high RC pressure trip will not actuate until the RC pressure at the core outlet exceeds the trip set-point by 60 psi.
3.
Low RC Pressure Trio.
The total RC pressure error is assu=ed to be +30 psi.
It is further assumed that the RC pressure at the hot leg tap is 30 psi less than the pressure at the core outlet.
All accident analysis calcu-lations assumed that the low RC pressure trip will not actuate until the RC pressure at the core outlet falls to the value of the trip setpoint.
4.
Hich RC Outlet Temperature.
The total RC temperature ceasurement error is
-1.0F.
All accident analysis calculations assume that the high RC outlet temperature trip will not actuate until the RC outlet temperature has ex-
'eceded the trip setpoint by 1.0F.
5.
Variable Low RC Pressure Trio.
This trip function uses both the RC outlet temperature measurecent and RC pressure measurement signals.
The errors for the input par.ameters are treated as per the descriptions in items 3 and 4.
Accident analysis calculations do not show a variable low pressure trip until the pressure and temperature parameters exceed the trip conditions by the amount of the assumed errors.
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a 6.
Power / Imbalance / Flow Trip This trip function requires measurement signals giving the flux in the top half of the core, the flux in the bottom half of the core, and the RC flow rate.
The flux measurement error is treated as in item 1.
(error = -6.5%
of rated power). The RC flow signal utilized in cl.is trip module is cali-brated to be less than the actual RC flou for all ci.nditions.
Therefore, it is not necessary to assume a flow measurement error.
The offset limits are error adjusted, according to the following equations and then the adjusted offset limits are converted to 1 balance septoints.
.9
=
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g R
R R
&g., G
+
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R R
R error adjusted offset limit where:
e
=
g
= real offset limit R
B
= incore to out-of-core detector bias E
= offset measurement error The errors used for the offset corrections are as follows:
Bias Of fset Measurement Error
'Oconee 1 0.126 0.068 Oconee 2,3 0.150 0.075 7.
. Flux /PuTrp Mcnitor Trio.
The flux measurement error is treated as in item 1.
One pump monitor is always assumed to be inoperative.
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