Term
IOP-5: Minimum Load To Hot Standby
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Definition
Outlines the sequence in which systems are removed from service during a plant shutdown from Mode 1 to Mode 3:
Complete final unloading of the turbine.
Reduce power level to Mode 2 and complete secondary plant shutdown.
Shutdown the reactor and enter Mode 3.
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Term
Precautions and Limitations
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Definition
Prerequisites
Reactor power <20%.
Tave at program value.
Tave program for 20% power is ~551°F.
Reactor power should be £ 8% if SG level control is on BF40 only.
For a planned Turbine Trip, the req’s of PT.TRB-0003 may be satisfied by direct observation of the control or governor valves during the trip, as long as there has been no evidence of malfunction of each valve during normal operation.
If MSIV closure is required, make sure that Gland Seal is supplied by somebody else!
If a manual Reactor Trip is planned and Steam Dumps are available, the Turbine should remain in service with the Dumps in Tave Control Mode for a smoother transition to EOP-TRIP-1.
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Term
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Definition
Attachment 1, Maintaining Minimum Temperature for Criticality, contains instructions for action required if Tave is £541°F.
≤535°F à you’re done; got to TRIP
The only time Rods can be used is after Tavg is rising (temp control regained) and:
RCS is now ≥541°F or <541°F for <15 minutes
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Bases for Minimum Temperature for Criticality (TS 3.1.1.4)
1) MTC is in the analyzed range (TS 3.1.1.3, max positive=0 delta k/k/°F, BOL, max negative= -4.4 E-4 delta k/k/°F, EOL)
2) Protective instrumentation within the operating range
3) P-12 interlock above setpoint (Tave >543°F)
4) PZR is capable of being operable with a steam bubble
5) Pressure vessel above RTNDT
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Term
| AFW Pump Operation for Shut down |
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Definition
If 23 AF pump is providing flow, the AF21s are run down to minimum and the motor-driven AF pumps are started. Feed is set to at least 10E4 lbm/hr to each SG prior to the trip to “reduce the likelihood” of an auto start.
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Term
| What are the capacities of the Steam Dump valves and what is total dump capacity? |
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Definition
Answer: Groups 1 and 2 valves - 3.33% steam flow/valve, Groups 3 and 4 valves - 5.33% steam flow/valve, total capacity ~52% steam flow.
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Term
Inputs, logic and purpose of P-10.
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Definition
Answer: 2/4 NIS Power Range channels >10%, allows manual blocking of Power Range High Flux Low setpoint (25%) and Intermediate Range High Flux trip setpoint (current equivalent for 25% power) .
NOTE: In this case, while lowering load, P-10 will be ENABLING automatic RPS trips vs allowing blocking. This is done automatically when 3/4 Power Range NI channels are <10%.
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Term
Describe the inputs, logic and purpose of P-7.
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Definition
Answer: Below P-7 energized (actuated) when both P-10 and P-13 conditions no longer exist (P-13, PT-505 and PT-506 both less than pressure equivalent of 10% load
P-10, 3/4 PR NIS channels <10% power).
Below P-7 automatically blocks:
1) PZR level high (92%) reactor trip on 2/3 channels,
2) PZR low pressure reactor trip 2/4 channels <1865 psig,
3) RCP bus undervoltage/underfrequency on H or E and F or G bus reactor trip,
4) Loss of flow in 2/4 loops sensed by 2/3 detectors per loop reactor trip (i.e., all RCPs could trip with no reactor trip)
2 RCP breakers open |
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Term
Inputs, logic, and purpose of P-6.
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Definition
Answer: 1/2 IR channels >1E-10 amps and rising actuates P-6 (deenergizes) and allows blocking of 1/2 SR High Flux trip at 1E5 cps (allows deenergizing SR High Voltage).
2/2 IR channels <7E-11 amps and lowering automatically unblocks SR High Flux trip (energizes SR High Voltage).
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