Term
| 1. Explain the purpose and function of the CRDH System. |
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Definition
The CRDH system provides high pressure water from the condensate line or condensate storage tanks to perform the following functions: Normal: Normal control rod motion Charge hydraulic control units Cooling water to control rod drives Recirc Seal Injection Reference Leg Backfill
Emergency: Feedwater to reactor vessel Alternate means of Boron injection.
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Term
| State the normal supply for CRDH and why |
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Definition
| Condensate (demin effluent); for low Oxygen content and low conductivity. This reduces the probability of CRD collet retainer tube cracking. |
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Term
| What is the alternate supply to CRDH? |
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Definition
| CST which has much higher Oxygen concentration and Conductivity than the Condensate. |
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Term
| Functional and component relationships between CRDH and Recirculation pumps |
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Definition
| Control rod drive hydraulics supplies water to the recirc pump seal injection system. |
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Term
| Functional and component relationships between CRDH and RWCU |
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Definition
| CRDH is capable of supplying water to the RPV in an emergency via the RWCU return line. |
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Term
| Functional and component relationships between CRDH and Instrument air |
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Definition
| Provides air to scram valves and Scram Discharge Volume vent and drain valves. |
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Term
| Functional and component relationships between CRDH and RPS |
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Definition
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Term
| Functional and component relationships between CRDH and 4160/480 Vac |
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Definition
4160 VAC: Power supply to CRD pumps. 480 VAC: Power supplies to Motor Operated Valves (MCC-141 or LC-104) |
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Term
| Functional and component relationships between CRDH and 125 Vdc |
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Definition
| Provides power to backup scram pilot valves which are energized open during a scram as backup method of venting scram air header in case of failure of scram pilot valves. |
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Term
| Functional and component relationships between CRDH and Condensate/condensate storage system |
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Definition
The CRD pump bypass flow line ties in between the CST heat exchanger and the CSTs to increase flow through the CRD pumps. Also, the condensate system supplies low oxygen, low conductivity water to the CRDH system. The CSTs supply less pure water in the event that the condensate system is not available (particularly during startup) |
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Term
| Functional and component relationships between CRDH and RBCCW |
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Definition
| RBCCW provides cooling for CRD pump thrust bearings and speed increaser oil cooler. |
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Term
| Functional and component relationships between CRDH and Reference Leg Backfill system |
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Definition
| CRDH injects water into the Reference Leg Backfill System to prevent non-condensabel gas migration into the reference leg. |
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Term
| 11. Explain the Design Basis for CRDH. |
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Definition
Safety related functional requirement: CRD/CRH is required to rapidly insert withdrawn control rods into the core (scram) in response to automatic signals from RPS. CRD/CRH is required to incrementally position neutron absorbing control rods within the reactor core in response to manual control signals. CRH SHALL supply water to the reactor recirc pump seal injection subsystem. CRH SHALL supply water to the RPV reference leg backfill system. CRD/CRH is required to rapidly insert withdrawn control rods into the core (scram) in response to manual signals from RPS. |
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Term
| Sequence of events on a Scram (from CRDH perspective) |
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Definition
From lesson plan STAGE 1: Scram pilot valves de-energize venting off scram air header pressure. Simultaneously, the 4 Scram Discharge Volume vent and drain valve solenoid valves de-energize, venting their valves and the header. Scram valves CV-126 and CV-127 open. Scram Discharge Volume vent/drain valves close. Rods are moved in to 90% travel position by accumulator and reactor pressure in less than 3.5 seconds on average. Less than 1 gallon of water is exhausted per rod during scram. STAGE 2: Charging water header to accumulator to under piston via CV-126 exhaust to Scram Discharge Volume. STAGE 3: all rods inserted, Scram Discharge Volume at reactor pressure, charging water header to accumulator to under piston via CV-126 to reactor (cool drive vessel makeup)." |
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Term
| Describe the different filters installed in the CRDH system. |
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Definition
| "Suction filters: 5 micron; two in parallel, one in operation. CUNO standby filter: 5 micron filter ensures flow through CRDMs with no CRD Pumps (source: Cond't service; used during outage); Drive water post filters: Removes rust, scale and other particulate matter greater than 20 microns." |
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Term
| Where do the CRD pumps get their power? What is the normal discharge pressure band? |
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Definition
| Essential busses (15 and 16); 1485 - 1500 psig. |
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Term
| What is the difference between the CRD pump minimum flow line and the bypass flow line? |
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Definition
The Minimum flow line is 1 inch and allows for 20 gpm flow back to the CST to provide cooling to the pump DURING NORMAL OPERATION. It also prevents damage due to overheating in the event of a closed discharge valve. The bypass flow line allows for more pump flow with partial or full isolation of CRD/HCU system. This line allows 25-30 gpm returned to CSTs via the CST heat exchanger discharge. |
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Term
| What is the significance of CRD-95 and CRD-165? |
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Definition
| "These are located just downstream of the bypass flow line. In case of loss of both CRD pumps, these check valves PREVENT THE BACK FLOW OF RPV WATER FROM THE HCUs TO THE CST OUTSIDE OF SECONDARY CONTAINMENT. In other words, they are secondary containment barriers." |
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Term
| Briefly describe the CRDH flow control station. |
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Definition
| "Maintains system flow at nominal 54-56 gpm with recirc pump seal injection in service, 48-50 gpm without." |
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Term
| What pressure does the Drive Water Pressure Station maintain? How is this accomplished? |
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Definition
| MO 3-20 is used to maintain Drive Header Pressure approximately 265 PSIG above Reactor Pressure. |
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Term
| "What is "normal rod movement"? How is this accomplished?" |
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Definition
| 3 inches per second. Accomplished by directional control valves 120 and 123 having integral speed control valves. |
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Term
| Describe the CRD pump mechanical seals. |
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Definition
| Supplied by cooling water from the pump casing. The standby pump is supplied with seal water from the operating pump which assures air in-leakage is minimized. |
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Term
| Describe the flow path for water from the exhaust header to the reactor vessel during a single control rod movement. |
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Definition
| "From exhaust header to the individual exhaust lines of the other 120 rods. Leaks past the respective SV-121 into the upper piston area. Leaks past the control rod drive seals and into the vessel. NOTE: during rod insertion, the drive's over piston water is displaced to the exhaust header. Similarly, during withdrawal, it is the under piston water that is displaced into the exhaust header." |
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Term
| Describe the equalizing valves in the CRDH system. |
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Definition
| "Normally closed, spring loaded, in line relief valves with cracking pressures of 75 and 85 PSID to permit a full open position flow of 2 gpm; fully closed at 60 PSID and max flow is limited to 10 gpm. NOTE: these valves only needed for fast recovery after a scram. NOT USED DURING PLANT STARTUP AND PRESSURIZATION." |
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Term
| What is the minimum Nitrogen pressure allowable and why? |
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Definition
| 940 psig assures that the control rod insertion times will satisfy tech spec criteria under cold scram (0 psig) conditions. |
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Term
| Power supply to CRD Pumps |
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Definition
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Term
| Power supply for flow control station |
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Definition
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Term
| Power supply for CRD Temperature Recorder and Scanner |
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Definition
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Term
| Power supply for MO-3-20 and MO-3-22 |
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Definition
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Term
| Tech Spec 3.1.1 LCO/Applicability and Conditions with less than or equal to one hour completion time |
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Definition
"Section 3.1: Reactivity Control Systems Tech Spec 3.1.1: Shutdown Margin LCO 3.1.1: Shutdown Margin shall be: Greater than or equal to 0.38% delta-k per k, with the highest worth control rod analytically determined; or greater than or equal to 0.28% delta-k per k, with the highest worth control rod determined by test.
APPLICABILITY: Modes 1, 2, 3, 4 and 5 CONDITION C: Shutdown Margin not within limits in MODE 3 REQUIRED ACTION C.1: Initiate action to fully insert all insertable control rods. COMPLETION TIME: Immediately. CONDITION D: Shutdown Margin not within limits in MODE 4. REQUIRED ACTIONS: D.1: Initiate action to fully insert all insertable control rods. COMPLETION TIME: Immediately. AND D.2: Initiate action to restore secondary containment to OPERABLE status; COMPLETION TIME: 1 hour AND D.3 Initiate action to restore one standby gas treatment subsystem to OPERABLE status. COMPLETION TIME: 1 hour AND D.4: Initiate action to restore isolation capability in each required secondary containment penetration flow path not isolate. COMPLETION TIME: 1 hour. CONDITION E. Shutdown Margin not within limits in MODE 5. REQUIRED ACTIONS: E.1: Suspend CORE ALTERATIONS except for control rod insertion and fuel assembly removal. COMPLETION TIME: Immediately AND E.2: Initiate action to fully insert all insertable control rods in core cells containing one or ore fuel assemblies. COMPLETION TIME: Immediately AND E.3: Initiate action to restore seoncdary containment to OPERABLE status. COMPLETION TIME: 1 hour AND E.4 Initiate action to restore one Standby Gas Treatment subsystem to OPERABLE status. COMPLETION TIME: 1 hour AND E.5 Initiate action to restore isolation capability in each required secondary containment penetration flow path not isolate. COMPLETION TIME: 1 hour." |
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Term
| Tech Spec 3.1.2 LCO/Applicability and Conditions with less than or equal to one hour completion time |
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Definition
Section 3.1: Reactivity Control Systems Tech Spec 3.1.2: Reactivity Anomalies LCO 3.1.2: The reactivity difference between the monitored control rod inventory and the predicted control rod inventory shall be within plus or minus 1% delta-k per k. APPLICABILITY: MODES 1 and 2 |
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Term
| Tech Spec 3.1.3 LCO/Applicability and Conditions with less than or equal to one hour completion time |
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Definition
Section 3.1: Reactivity Control Systems Tech Spec 3.1.3: Control Rod OPERABILITY LCO 3.1.3 Each control rod shall be OPERABLE. APPLICABILITY: MODES 1 and 2. CONDITION A: One withdrawn control rod stuck. REQUIRED ACTIONS: --NOTE-- Rod Worth Minimizer may be bypassed, if required, to allow continued operation. A.1 Verify stuck control rod criteria are met. COMPLETION TIME: Immediately. AND... (not 1 hour or less)... |
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Term
| Tech Spec 3.1.4 LCO/Applicability and Conditions with less than or equal to one hour completion time |
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Definition
Section 3.1: Reactivity Control Systems Tech Spec 3.1.4: Control Rod Scram Times LCO 3.1.4: a. No more than 8 OPERABLE control rods shall be ""slow,"" in accordance with Table 3.1.4-1, and b. No more than 2 OPERABLE control rods that are ""slow"" shall occupy adjacent locations. APPLICABILITY: MODES 1 and 2. |
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Term
| Tech Spec 3.1.5 LCO/Applicability and Conditions with less than or equal to one hour completion time |
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Definition
Section 3.1: Reactivity Control Systems Tech Spec 3.1.5: Control Rod Scram Accumulators LCO 3.1.5: Each control rod scram accumulator shall be OPERABLE. APPLICABILITY: MODES 1 and 2. CONDITION B: Two or more control rod scram accumulators inoperable with reactor steam dome pressure greater than or equal to 900 psig. ACTIONS: B.1 Restore charging water header pressure to greater than or equal to 940 psig. COMPLETION TIME: 20 minutes from discovery of Condition B concurrent with charging water header pressure less than 940 psig. AND --B.2.1 NOTE-- Only applicable if the associated control rod scram time was within the limits of Table 3.1.4-1 during the last scram time Surveillance. Declare the associated control rod scram time "slow" OR B.2.2 Declare the associated control rod inoperable. Both Completion times are 1 hour.
CONDITION C: One or more control rod scram accumulators inoperable with reactor steam dome pressure less than 900 psig. REQUIRED ACTIONS: C.1 Verify all control rods associated with inoperable accumulators are fully inserted. COMPLETION TIME: Immediately upon discovery of charging water header pressure less than 940 psig. AND C.2: Declare the associated control rod inoperable. COMPLETION TIME: 1 hour. CONDITION D: Required Action B.1 or C.1 and associated Completion Time not met. REQUIRED ACTION: --NOTE-- Not applicable if all inoperable control rod scram accumulators are associated with fully inserted control rods. Place the reactor mode switch in the shutdown position. COMPLETION TIME: Immediately. |
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Term
| Tech Spec 3.1.8 LCO/Applicability and Conditions with less than or equal to one hour completion time |
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Definition
Section 3.1: Reactivity Control Systems Tech Spec 3.1.8: Scram Discharge Volume Vent and Drain Valves LCO 3.1.8: Each Scram Discharge Volume Vent and Drain valve shall be OPERABLE APPLICABILITY: MODES 1 and 2. |
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Term
| What are the stuck control rod criteria? |
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Definition
| A control rod is considered stuck if it will not insert by either CRD drive water or scram pressure. |
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Term
| What are the stuck control rod separation criteria? |
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Definition
Stuck control rod separation criteria are not met if: a) the stuck control rod occupies a location adjacent (face or diagonal) to two "slow"" control rods, b) the stuck control rod occupies a location adjacent to one "slow" control rod, and the one "slow" control rod is also adjacent to another ""slow"" control rod, or c) if the stuck control rod occupies a location adjacent to one "slow" control rod when there is another pair of "slow" control rods elsewhere in the core adjacent to one another"
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