ML021340091
| ML021340091 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee  |
| Issue date: | 05/10/2002 |
| From: | NRC/NRR/DLPM |
| To: | Vermont Yankee |
| References | |
| TAC MB3430 | |
| Download: ML021340091 (5) | |
Text
VYNPS TABLE 3.2.6 POST-ACCIDENT INSTRUMENTATION minimum Number of operable Instrument Type of Indication Instrument Range Parameter channels (Note 8')
0-350°F Recorder #TR-16-19-45 2 Drywell Atmospheric (Blue)
Temperature (Notcs 1 and 3) 0-350OF I Meter #TI-16-19-30B
(-15) -(+260) psig Meter #PI-16-19-12A 2 Containment Pressure (-15) -(+260) psig Meter #PI-16-19-12B (Notes 1 and 3)
II Meter #PI-16-19-36A
(-15) -(+65) psig Torus Pressure (Notes 1 and 3) (-15) -(+65) psig 2 Meter #PI-16-19-36B Meter #LI-16-19-12A 0-25 ft.
2 Torus Water Level 0-25 ft.
Meter #LI-16-19-12B (Notes 1 and 3)
I Meter #TI-16-19-33A 0-250°F Torus Water Temperature 0-250OF 2 Meter #TI-16-19-33C (Notes 1 and 3)
I Meter #PI-2-3-56A 0-1500 psig Reactor Pressure 0-1500 psig I 2 (Notes 1 and 3)
Meter #PI-2-3-56B Meter #LI-2-3-91A (-200) (+200) "H20 Reactor Vessel Water Level (-200) (+200) "1HO 2 Meter #LI-2-3-91B (Notes 1 and 3)
I Recorder #TR-16-19-45 0-350°F I 2 Torus Air Temperature (Notes 1 and 3)
(Red) 50-300°F Meter #TI-16-19-41 Lights RV-2-71(A-D)
Closed - Open Safety/Relief Valve Position 2/valve From PS-2-71-(1-3) (A-D)
From Pressure Switches (Notes 1 and 3)
I 53 No. 5-, -6, 9", 3-, +/-+/-a, +/-4-5, +/-
+/--6-, , 207 Amendment
VYNPS TABLE 3.2.6 (Cont' d)
POST-ACCIDENT INSTRUMENTATION Minimum Number of operable Instrument Type of Indication Instrument Range Channels (Note 8) Parameter Closed - Open Meter ZI-2-1A/B 1/valve Safety Valve Position From Acoustic Monitor (Note 5)
Recorder SR-VG-6A (SI) 0-30% hydrogen 2 Containment Hydrogen/Oxygen 0-25% oxygen Recorder SR-VG-6B (SII)
Monitor (Notes 1 and 3) 7 Meter RM-16-19-lA/B 1 R/hr-10 R/hr 2 Containment High-Range Radiation Monitor (Note 6) 0.1 - 107 mR/hr Meter RM-17-155 1 Stack Noble Gas Effluent (Note 7) 54 Amendment No. - 94,- 9-6, 94-, 1ý4, l8_, 207
VYNPS TABLE 3.2.6 NOTES Note 1 - Within 30 days following the loss of one indication, restore the inoperable channel to an ope~fable status or a special report to the 14 Commission must be prepared and submitted within the subsequent and days, outlining the action taken, the cause of the inoperability, the plans and schedule for restoring the system to operable status.
Note 2 - Deleted.
restore at least Note 3 - Within 7 days following the loss of both indications, reactor in a one required channel to an operable status or place the hot shutdown condition within the following 12 hours.
Note 4 - Deleted.
the acoustic Note 5 - From and after the date that safety valve position from for 30 days monitor is unavailable, reactor operation may continue provided safety valve position can be determined by monitoring safety If after valve discharge temperature and primary containment pressure.
30 days the inoperable channel has not been returned to an operable status, a special report to the Commission must be prepared and submitted within the subsequent 14 days, outlining the action taken, the cause of the inoperability, and the plans and schedule for restoring the system to operable status.
If one or both parameters are not available (i.e., safety valve discharge temperature and primary containment pressure indication) with one or more safety valve position indications from the acoustic monitor unavailable, continued reactor operation is permissible during the next In this condition, if both secondary parameters are not seven days.
seven days, the reactor shall be restored to an operable status within shutdown condition within the following 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
placed in a hot days Note 6 - Within 30 days following the loss of one indication, or seven following the loss of both indications, restore the inoperable channel(s) to an operable status or a special report to the Commission must be prepared and submitted within the subsequent 14 days, outlining and the action taken, the cause of the inoperability, and the plans schedule for restoring the system to operable status.
by Control Note 7 - From and after the date that this parameter is unavailable Room indication, within 72 hours ensure that local sampling capability is available. If the Control Room indication is not restored within 14 days 7 days, prepare and submit a special report to the NRC within the taken, the cause of following the event, outlining the action system to inoperability, and the plans and schedule for restoring the operable status.
Note 8 - When a channel is placed in an inoperable status solely for performance of required surveillances, entry into associated Limiting Conditions to 6 for Operation and required action notes may be delayed for up hours.
+/- +/-,-- , 207 55 Amendment No. , 16-, i*, 9--, +/-+/-'B', +/-9-3i-,+/-+5, +/--8-,
VYNPS BASES: 3.2 (Cont'd)
Specification 3.2.G requires that the post-accident monitoring (PAM) instrumentation of Table 3.2.6 be operable during reactor power operation.
PAM instrumentation is not required to be operable during shutdown and refueling conditions when the likelihood of an event that wouldtherequire PAM PAM instrumentation is extremely low. The primary purpose of instrumentation is to display plant variables that provide information This required by the control room operators during accident situations. the information provides the necessary support for the operator to take that are manual actions for which no automatic control is provided and required for safety systems to accomplish their safety functions for design basis accidents. The operability of the PAM instrumentation ensures that there is sufficient information available on selected plant an parameters to monitor and assess plant status and behavior following of accident. This capability is consistent with the recommendations Regulatory Guide 1.97, "Instrumentation for Light Water Cooled Nuclear Following Power Plants to Assess Plant and Environs Conditions During and an Accident."
to In most cases, Table 3.2.6 requires a minimum of two operable channels the information necessary to ensure that the operators are provided determine the status of the plant and to bring the plant to, and maintain it in, a safe condition following an accident. For the majority of parameters monitored, when one of the required channels is inoperable, the required inoperable channel must be restored to operable status within 30 The 30-day completion time is based on operating experience and days. a channel (or in the case of takes into account the remaining operable only one required channel, an alternate means to parameter that has monitor the parameter), the passive nature of the instrument (no critical the low automatic action is assumed to occur from these instruments), and probability of an event requiring PAM instrumentation during this interval.
If a PAM instrument channel has not been restored to an operable status a written within the specified interval, the required action is to prepare This report to be submitted to the NRC within the following 14 days.
the report will detail the corrective actions taken, an evaluation ofschedule proposed restorative actions, and a cause of the inoperability, for returning the inoperable system to service. This action is appropriate in lieu of a shutdown requirement, since alternative actions are identified before loss of functional capability, and given the by likelihood of plant conditions that would require information provided this instrumentation.
For the majority of PAM instrumentation, when two required channels are one inoperable (or in the case of a parameter that is monitored by only channel, the channel and an alternate means are inoperable), one channel status (or the required alternate means) should be restored to an operablethe within seven days. The completion time of seven days is based on and relatively low probability of an event requiring PAM instrumentation the normal availability of alternate means to obtain the required information. Where specified, continuous operation with two required channels inoperable (or one channel and the required alternate means inoperable) is not acceptable after seven days. Therefore, restoration of one inoperable channel limits the risk that the PAM function will be in a degraded condition should an accident occur.
+/-i--, , - +/--, 207 79 Amendment No.9-, , +/-+/--17,
VYNPS BASES: 3.2 (Cont'd)
For the majority of PAM instrumentation in Table 3.2.6, if two of the required channels (one required channel per valve and alternate means for safety valve position indication) remain inoperable beyond the allowed interval, actions must be taken to place the reactor in a mode or condition in which the limiting condition for operation does not apply. To achieve this status, the reactor must be brought to at least hot shutdown within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The allowed completion time is reasonable, based on operating experience, to reach the required plant conditions from full power conditions in an orderly manner and without challenging plant systems. It is not necessary to bring the reactor to cold shutdown since plant conditions during hot shutdown are such that the likelihood of an accident that would require PAM instrumentation is extremely low.
The Degraded Grid Protective System has been installed to assure that safety-related electrical equipment will not be subjected to sustained degraded voltage. This system incorporates voltage relays on 4160 Volt Emergency Buses 3 and 4 which are set to actuate at the minimum voltage required to prevent damage of safety-related equipment.
If Degraded Grid conditions exist for 10 seconds, either relay will actuate an alarm to alert operators of this condition. Based upon an assessment of these conditions the operator may choose to manually disconnect the off-site power. In addition, if an ESF signal is initiated in conjunction with low voltage below the relay setpoint for 10 seconds, the off-site power will be automatically disconnected.
The Reactor Core Isolation Cooling (RCIC) System provides makeup water to the reactor vessel during shutdown and isolation to supplement or replace the normal makeup sources without the use of the Emergency Core Cooling Systems. The RCIC System is initiated automatically upon receipt of a reactor vessel low-low water level signal. Reactor vessel high water level signal results in shutdown of the RCIC System.
However, the system will restart on a subsequent reactor vessel low-low water level signal. The RCIC System is normally lined up to take suction from the condensate storage tank. Suction will automatically switch over from the condensate storage tank to the suppression pool on low condensate storage tank level.
Upon receipt of a LOCA initiation signal, if normal AC power is available, all RHR pumps and both Core Spray pumps start simultaneously with no intentional time delay. If normal AC power is not available, RHR pumps A and D start immediately on restoration of power, RHR pumps B and C start within 3 to 5 seconds of restoration of power and both Core Spray pumps start within 8 to 10 seconds of restoration of power. The purpose of these time delays is to stagger the start of the RHR and Core Spray pumps on the associated Division 1 and Division 2 Buses, thus limiting the starting transients on the 4.16 kV emergency buses. The time delay functions are only necessary when power is being supplied from the standby power sources (EDGs). The time delays remain in the pump start logic at all times as the time delay relay contact is in parallel with the Auxiliary Power Monitor relay contact. Either contact closure will initiate pump start. Thus, the time delays do not affect low pressure ECCS pump operation with normal AC power available. With normal AC power not available, the pump start relays which would have started the B and C RHR pumps and both Core Spray pumps are blocked by the Auxiliary Power Monitor contacts and the pump start time delay relays become the controlling devices.
Amendment No. 207 79a