ML20137L973
| ML20137L973 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 01/14/1986 |
| From: | DUQUESNE LIGHT CO. |
| To: | |
| Shared Package | |
| ML20137L955 | List: |
| References | |
| NUDOCS 8601280158 | |
| Download: ML20137L973 (5) | |
Text
_ -..
._- - =
5 e
4 m
i y
TABLE 2.2-1 (Continued)
REACTOR TRIP SYSTEM INSTRUMENTATION TRIP SETPOINTS I
N NOTATION 5
i 5
S)/
2 (1+t1 STT[ 1 T-T'
+ K3 (P-P') -f (AI')
, NOTE 1:
Overtemperature AT[ 1 K -K
< AT 1
o 1+t2S/ - \\l+TSS/-
\\ 1+t 4 s*
=
Indicated AT at RATED THERMAL POWER where:
ATo e
Average temperature, "F
T
=
576.3*F (indicated T at RATED THERMAL POWER)
T'
=
avg
. Pressurizer pressure, psig P
=
"g 2235 psig (indicated RCS nominal operating pressure)
P'
=
m
.The function generated by the lead-lag' controller for T dynamic
@m 1+t1 S
=
avg g4 1+T2S compensation.
tl & T2 Time constants utilize.d in the lead-lag controller for T
=
avg g
11.= 30 secs, x2 = 4 secs.
Lag compensator on measured AT 1
=
1+t4S i
t4 Time constant utilized in the lag compensator for AT,
=
T4 value selectad sucn that Overtemperature AT reactor trip response
[
t time is less than Table 3.3-2 time.
l Lag compensator on measured Tavg 1
=
1+tSS Time constant utilized in the lag compensator-for Tavg, 4
1
=
3
}
T5 value selected such that Overtemperature AT reactor trip response time is less than Table 3.3-2 time.
Laplace transform operator.
5 S
.=
8601280159 860114.
PDR ADOCK 05000334 P
PDR "w.
+
pcwT w
w m
w e
y TABLE 2.2-1 (Continued)
REACTOR TRIP SYSTEM INSTRUMENTATION TRIP SETPOINTS x
NOTATION
>ep
< NOTE 2:
Overpower AT 1
} I ATO 5 (1+t3T2S T (
1 TT-K6 T( 1
-T"
-f(aI)
K -K 4
i 1+t4S/
(
S/ \\l+T5S/
- \\1+T5S C
Indicated AT at RATED THERMAL POWER
$ where:
ATo
=
e Average temperature, "F
p T
=
Indicated T at RATED THERMAL POWER 1 576.3*F' T"
=
avg
=
1.07 K4 m
K5 0.02/*F for increasing average temperature
=
a
=
0.00128 for T > T"; K6 = (0) for T 1 T" g
K6 m
The function generated by the rate lag controller for T dynamic
$w T3s
=
avg
,y, 1+T3s compensation oc g
t3 Time constant utilized in the rate lag controller for T
-t
= 10 secs.
=
- avg, H
1
=
Lag compensator on measured AT 1+t4S T4 Time _ constant utilized in the lag compensator for AT,
=
T4 value selected such that Overtemperature AT reactor trip response t h 'is less than Table 3.3-2 time.
Lag compensator on measured Tavg 1
=
1+t5S T5 Time constant utilized in the lag compensator for Tavg,
=
T5 value selected such that Overtemperature AT reactor trip response time is-less than Table 3.3-2 time.
Laplace transform operator.
S
=
f(AI)
=
0 for all AI NOTE 3:
.The channel's maximum trip, point shall not exceed its computed trip point by more than 4 percent.
_. _ _ _.. _ ~ _ _ _. _ _ _. _..
m M>
N TABLE 3.3-2 x
j REACTOR TRIP SYSTEM INSTRUMENTATION RESPONSE TIMES e
M<
i FUNCTIONAL UNIT RESPONSE TIME CZ He 1.
Manual Reactor Trip NOT APPLICABLE g
2.
Power Range, Neutron Flux 1 0.5 seconds *
\\
3.
Power Range, Neutron Flux, m
High Positive Rate o
5 4.
Power Range, Neutron Flux, Os High Negative Rate 1 0.5 seconds
- Mu 1
0 y 5.-
Intermediate Range, Neutran Flux NOT APPLICABLE o so jj 6.
Source Range, Neutron Flux NOT APPLICABLE H
7.
Overtemperature AT 1 4.0 seconds
- l 8.
Overpower AT NOT APPLICABLE 9.
Pressurizer Pressure--Low 1 2.0 seconds 10.
Pressurizer Pressure--High 1 2.0 seconds l
11.
Pressurizer Water Level--High NOT APPLICABLE
- Neutron detectors are exempt from response time testing.
Response time shall be measured from detector output or input of first electronic component in channel.
i k
ATTACHMENT 8 No Significant Hazard Determination Proposed Change Request No. 116 amends the Beaver Valley Power Station, Unit No.
1 Technical Specifications to include lag compensation factors in the overtemperature delta T and overpower delta T equations specified in Table 2.2-1.
In addition, the overtemperature delta T response time has been revised from 6 seconds to 4 seconds.
Basis for proposed no significant hazards determination:
It has been determined that spurious trip signals on the overtemperature delta T channels are due to the fast response of the Rosemount RTD's which replaced the slower response Sostman RTD's.
Circuit modifications were proposed to wire in existing unused filters which were provided in the instrument channel to permit the use of various RTD's having different response times.
By wiring these filters into the circuit, lag compensation will be provided to filter the process noise in the delta T and Tavg summators.
The lag units will have time constants of approximately 1.2 seconds and will increase the total circuit response time, however,
- 51s additional time will not result in exceeding the response time assumed in the accident analysis.
This proposed technical specification change will incorporate lag compensation factors into the overtemperature delta T and overpower delta T equations specified in Table 2.2-1 to incorporate the affects of the lag units.
Also the overtemperature delta T response time specified in Table 3.3-2 has been revised from 6 seconds to 4 seconds to reflect the accident analysis assumptions.
Based on the criteria for defining no significant hazards consideration setforth in 10 CFR 50.92(c), plant operation in accordance with the proposed amendment would not:
(1) involve a significant increase in the probability or consequences of an accident previously evaluated since this change will allow the installation of circuit modifications to provide the capability to filter RTD process noise caused by the fast response Rosemount RTD's and avoid spurious reactor trips generated on these channels.
These circuit modifications will be accounted for in the lag compensation factors specified in the proposed overtemperature delta T and overpower delta T equations.
Revision to the overtemperature delta T response time from 6 seconds to 4 seconds will not involve a significant increase in the probability or consequences of an accident previously evaluated since this change reflects the assumptions used in the safety analysis.
The safety analysis assumptions forming the basis for 6 seconds include a 2 second delay. attributable to coolant transit and thermai lag response time associated with the RTD bypass manifold coolant temperature measurement.
Therefore, the measurable 4-second time response is the interval from when the parameter exceeds its setpoint at the chanael sensor until loss of gripper coil voltage and does not include the transit and thermal lag time, which is not measurable.
s
Attachment B Pcg2 2
~
(2) create the possibility of a new or different kind of accident from any previously evaluated since the lag compensation for 'the delta T and Tavg circuits will be accounted for in the equations and the overtemperature delta T response time reflects the safety analysis assumptions.
(3) involve a significant reduction i n' the margin of safety since circuit modifications will be incorporated to filter process noise from the instrument loops to avoid spurious trip signals and the revised overtemperature delta T response time reflects the safety analysis assumptions.
The proposed changes to the overtemperature delta T and overpower delta T equaticns will allow the installation of lag compensation to filter RTD process noise and to avoid spurious reactor trip signals.
The lag compensation will be accounted for in the proposed overtemperature delta T and overpower delta T equations.
Revising the overtemperature delta T response time to 4 seconds reflects the safety analysis ass _mptions.
Therefore, the proposed changes will not increase the likelihood of a malfunction of safety-related equipment, increase the consequences of an accident previously analyzed, nor create the possibility of a malfunction different than previously evaluated.
Based on the above, it is proposed to characterize the change as involving a no significant hazard consideration.
-.