ML051920276
| ML051920276 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 07/07/2005 |
| From: | NRC/NRR/DLPM |
| To: | |
| References | |
| TAC MB9091 | |
| Download: ML051920276 (5) | |
Text
VYNPS TABLE 4.1.1 SCRAM INSTRUMENTATION AND LOGIC SYSTEMS FUNCTIONAL TESTS MINIMUM FUNCTIONAL TEST FREQUENCIES FOR SAFETY INSTRUMENTATION, LOGIC SYSTEMS AND CONTROL.CIRCUITS Instrument Channel Mode Switch in Shutdown Manual Scram IRM High Flux(10 )
Group 3)
A A
Functional Test(7)
Place Mode Switch in Shutdown Trip Channel and Alarm Minimum Frequency(4)
Each Refueling Outage Every 3 Months Within 31 Days Before Entering STARTUP/HOT STANDBY"')
1 and Every 31 Days During STARTUP/HOT STANDBY, Every 31 Days During Refueling C
Trip Channel and Alarm( 5)
Inoperative C
Trip Channel and Alarm Within 31 Days Before Entering STARTUP/HOT STANDBY"') and Every 31 Days During STARTUP/HOT STANDBY, Every 31 Days During Refueling APRM High Flux High Flux (Reduced)
B B
Trip Output Relays(5)
Trip Output Relays{5 )
Every 3 Months Before Each Startup & Weekly During Refueling(6 )
Every 3 Months Every 3 Months Inoperative Flow Bias B
Trip Output Relays B
Trip Output Relays(s)
High Reactor Pressure High Drywell Pressure Low Reactor Water Level(2)(8 )
High Water Level in Scram Discharge Volume Main Steam Line Iso. Valve Closure Turbine Con. Valve Fast Closure Turbine Stop Valve Closure Scram Test Switch (5A-S2(A-D))
First Stage Turbine Pressure -
Permissive (PS-5-14(A-D))
B B
B B
A A
A A
A Trip Trip Trip Trip Trip Trip Trip Trip Trip Channel Channel Channel Channel Channel Channel Channel Channel Channel and and and and and and and and and Alarm(5)
Alarm(5)
Alarm(5)
Alarm(5)
Alarm Alarm Alarm Alarm Alarm Every Every Every Every 3
3 3.
3 Months Months Months Months Every 3 Months Every 3 Months Every 3 Months Once each week (9)
Every 6 Months Amendment No. 44, G4E, 5,
-s, 4-64, 486, GE4, 225 25
VYNPS TABLE 4.1.1 NOTES
- 1.
Not used
- 2.
An instrument check shall be performed on reactor water level and reactor pressure instrumentation once per day.
- 3.
A description of the three groups is included in the basis of this Specification.
- 4.
Functional tests are not required when the systems are not required to be operable or are tripped.
If tests are missed, they shall be performed prior to returning the systems to an operable status.
- 5.
This instrumentation is exempted from the Instrument Functional Test Definition (1.G.).
This Instrument Functional Test will consist of injecting a simulated electrical signal into the measurement channels.
- 6.
Frequency need not exceed weekly.
- 7.
A functional test of the logic of each channel is performed as indicated.
This coupled with placing the mode switch in shutdown each refueling outage constitutes a logic system functional test of the scram system.
- 8.
The water level in the reactor vessel will be perturbed and the corresponding level indicator changes will be monitored. This test will be performed every month.
- 9.
The automatic scram contactors shall be exercised once every week by either using the RPS channel test switches or performing a functional test of any automatic scram function.
If the contactors are exercised using a functional test of a scram function, the weekly test using the RPS channel test switch is considered satisfied.
The automatic scram contactors shall also be exercised after maintenance on the contactors.
- 10.
When the IRM-High Flux trip function is required to be operable, an instrument check shall be performed on IRM instrumentation once per day.
- 11.
Not required to be performed when entering STARTUP/HOT STANDBY MODE from RUN MODE until 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after entering STARTUP/HOT STANDBY MODE.
Amendment No.
GE, G-&, 4-8-,
G, 225 2 6
VYNPS TABLE 4.1.2 SCRAM INSTRUMENT CALIBRATION MINIMUM CALIBRATION FREQUENCIES FOR REACTOR PROTECTION INSTRUMENT CHANNELS Instrument Channel Group (1)
Calibration Standard(4)
Standard Voltage Source Minimum Frequency(2)
Once/Operating Cycle I
High Flux IRM Output Signal(7)(10) (1)
C High Flux APRM Output Signal Output Signal (Reduced) (7)
Flow Bias B
B B
BC5)
Heat Balance Heat Balance Standard Pressure Source Using TIP System Standard Pressure Standard Pressure Standard Pressure Water Level and Voltage Source Source Source Once Every 7 Days Once Every 7 Days Refueling Outage Every 2,000 MWD/T average core exposure (8)
Once/Operating Cycle Every 3 Months Once/Operating Cycle Once/Operating Cycle High Reactor Pressure Turbine Control Valve Fast Closure High Drywell Pressure High Water Level in Scram Discharge Volume Low Reactor Water Level Turbine Stop Valve Closure First Stage Turbine Pressure Permissive (PS-5-14(A-D))
Main Steam Line Isolation Valve Closure B
A B
B B
A A
A Standard Pressure Source (6)
Pressure Source (6)
Once/Operating Cycle Refueling Outage Every 6 Months and After Refueling Refueling Outage Amendment No. 44, G4, As, i-, 64, 7-6, 4-64, 46, 49-L, 214, 225 27
VYNPS TABLE 4.1.2 NOTES
- 1.
A description of the three groups is included in the bases of this Specification.
- 2.
Calibration tests are not required when the systems are not required to be operable or are tripped.
If tests are missed, they shall be performed prior to returning the systems to an operable status.
- 3.
Deleted.
- 4.
Response time is not part of the routine instrument check and calibration, but will be checked every operating cycle.
- 5.
Does not provide scram function.
- 6.
Physical inspection and actuation.
- 7.
The IRM and SRM channels shall be determined to overlap during each startup after entering the STARTUP/HOT STANDBY MODE and the IRM and APRM channels shall be determined to overlap during each controlled shutdown, if not performed within the previous 7 days.
- 8.
The specified frequency is met if the calibration is performed within 1.25 times the interval specified, as measured from the previous performance.
- 9.
APRM trip unit calibration only.
- 10.
Neutron detectors are excluded.
- 11.
Not required to be performed when entering STARTUP/HOT STANDBY MODE from RUN MODE until 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after entering STARTUP/HOT STANDBY MODE.
Amendment No.
Q4., 4-8, 4-91, 24-,
24-9, 225 28
VYNPS BASES: 4.1 (Cont'd)
The calibration of the APRM High Flux Flow Bias trip units provides a check of the actual trip setpoints.
If the trip setting is found to be less conservative than accounted for in the appropriate setpoint calculation, but is not beyond the Allowable Value specified in Table 3.1.1, the channel performance is still within the requirements of the plant safety analysis.
However, if the trip setting is found to be less conservative than the Allowable Value specified in Table 3.1.1, the channel should be declared inoperable.
Under these conditions, the setpoint should be readjusted to be equal to or more conservative than accounted for in the appropriate setpoint calculation.
The specified trip unit calibration frequency (i.e., every 3 months) is consistent with the assumptions of the VYNPS setpoint methodology and the reliability analysis of NEDC-30851-P-A, "Technical Specification Improvement Analyses for BWR Reactor Protection System," March 1988.
IRM surveillance requirements are modified by Note 11 to Table 4.1.1 and Note 11 to Table 4.1.2 for functional and calibration testing, respectively.
These Notes allow functional testing and calibration of IRM instrument channels to be performed within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> of entering the STARTUP/HOT STANDBY MODE from the RUN MODE.
This allowance is necessary since testing of IRM instrument channels cannot be performed in the RUN MODE without utilizing jumpers, lifted leads, or movable links.
The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> time period is considered to provide reasonable time to complete testing.
The IRM calibration requirements are modified by Note 10 to Table 4.1.2 to exclude neutron detectors from calibration of the IRM - High Flux instrument channels. This is acceptable because the neutron detectors are passive devices with minimal drift, and because of the difficulty of simulating a meaningful signal.
LPRM gain settings are determined from the local flux profiles measured by the Traversing Incore Probe (TIP) System.
This establishes the relative local flux profile for appropriate representative input to the APRM System.
The 2,000 megawatt-days per short ton (MWD/T) frequency is based on operating experience with LPRM sensitivity changes, and that the resulting nodal power uncertainty, combined with other identified uncertainties, remains less than the total uncertainty (i.e., 8.7%) allowed by the GETAB safety limit analysis.
Amendment No. 4G, 4, 4-9-1, 2414,225 33a