Term
| Explain the purpose and function of the IRM system. |
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Definition
| To provide neutron flux indication from the upper limits of the SRMs to the lower limit of the power range monitors; and actuate rod blocks or scram if neutron flux exceeds a safe level. |
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Term
| "Identify the Normal, Alternate, and or Emergency power supplies for major IRM system components." |
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Definition
"IRMs are powered from the 24/28 Vdc system. Channels 11, 12, 13 and 14 are from panel D-15 (15 Battery), 15, 16, 17 and 18 from D-25 (14 Battery); Y-20 supplies power to the detector drive control relays; Lighting Panel L-38 provides power to the detector drive motors." |
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Term
| Functional and component relationships between the IRM and ± 24 Vdc battery system |
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Definition
IRM Channels 11, 12, 13 and 14 receive power from panel D-15 (15 Battery); IRM Channels 15, 16, 17 and 18 from D-25 (14 Battery) |
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Term
| Functional and component relationships between the IRM and 120 V instrument AC system |
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Definition
Detector drive control relays receive power from Y-20. |
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Term
| Functional and component relationships between the IRM and 208 Volt lighting panel L-38 |
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Definition
| Detector drive motors receive power from 208 Volt Lighting panel L-38 |
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Term
| Functional and component relationships between the IRM and SRM system |
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Definition
| "In range 3 or above on the IRM channels, the SRM detector RETRACT PERMIT and DOWNSCALE rod blocks are bypassed. Above range 7 on the IRM channels or with MODE switch in RUN, all rod blocks initiated by SRM channels are bypassed." |
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Term
| Functional and component relationships between the IRM and Reactor manual control system (RMCS) |
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Definition
| "RMCS receives rod blocks from the IRM instruments if IRM is HIGH, DOWNSCALE, or INOP. IRM also inserts rod block if detector is not fully inserted before placing mode switch to RUN." |
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Term
| Functional and component relationships between the IRM and Reactor protection system (RPS) |
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Definition
| IRM provides trip signals to RPS when IRM is HIGH-HIGH or INOP. Signals are bypassed when mode switch is in RUN and associated APRM is not downscale. |
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Term
| Functional and component relationships between the IRM and Reactor vessel |
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Definition
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Term
| Describe the different positions of the IRM function switch. |
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Definition
"OPERATE: IRM is in normal op mode with all trips operable; STANDBY: same as OPERATE except INOP trip to warn operator channel being tested, half scram plus rod block if Mode switch not in 'run'; ZERO 1: Disconnects output amp to zero meters; ZERO 2: Disconnects Mean Square Analog Unit for zero adjustments; 125: checks 125 position; 40: NOT USED." |
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Term
| IRM Voltage Pre-amp function and description. |
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Definition
| "Accepts current pulses from detector and converts to voltage pulses, amplifies the AC pulse and sends it to the CR. Depending on range selected, will only allow certain frequencies to pass." |
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Term
| IRM Amplifier and Attenuator purpose and function. |
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Definition
| "Depending on range selected, it maintains its output in range for the inverter and Mean Square Analog Unit. Works with Diode logic matrix to adjust gain or IRM signal based on range switch position" |
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Term
| IRM Mean Square Analog Unit purpose and function |
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Definition
| Does its best to discriminate the neutron pulses from the gamma pulses by squaring the input signal. This is because pulse counting (as in SRMs) is impractical due to pulses almost being continuous. |
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Term
| Impact/consequences IRM stuck detector drive |
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Definition
| "If the IRM is stuck, it may accumulate excessive amounts of exposure, which leads in turn to high dose rates when the detector is changed out. This will be true even if a long time (years) elapses between the exposure accumulation and the changeout. Therefore, it is important to be able to determine the accumulated dose." |
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Term
| Explain the Design Bases for the IRM system. |
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Definition
| Detect and indicate neutron flux level in a range between SRM detection capability and the power range instrumentation capability. Also, generate trip signals to prevent FUEL DAMAGE from single operator errors or single equip malfunctions. |
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Term
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Definition
| Drive in ONLY; but must press (drive-in) button again to reset seal-in when full in in order to drive out. |
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Term
| Total stroke length and speed of IRM drive mechanism. |
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Definition
| 10 feet in length at 3 feet per minute |
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Term
| Function of IRM Detector Drive system |
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Definition
| Allows SRM detectors to be vertically positioned from 2 feet above the core centerline to 2 feet below the core. |
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Term
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Definition
"less than 5 units out of 125.Results in rod block. Bypassed if: On IRM range 1; IRM bypassed, MODE switch in 'RUN'."
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Term
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Definition
| 108 units out of 125. Results in a rod block Bypassed if IRM bypassed or MODE switch in 'RUN'. |
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Term
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Definition
| "120 units out of 125. Results in an RPS half scram unless IRM is bypassed, or MODE switch is in 'RUN'." |
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Term
| Conditions for IRM INOP and system response |
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Definition
Module unplugged, Function switch out of OPERATE, Loss of Detector Voltage and/or loss of 24 Vdc, Pre-amp disconnected, Range Switch disconnected.
System response: Rod block and half scram. |
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Term
| "When an IRM is at the high end of its highest range (120 units of 125), what is the corresponding reactor power?" |
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Definition
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Term
| "Compare indication of two different ranges. In other words, by what factor does the indication change when ranging up/down?" |
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Definition
| Adjacent ranges differ by a factor or the square root of 10 (or 3.16… approximately 3). |
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Term
| Which IRMs are associated with RPS A? |
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Definition
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Term
| Which IRMs are associated with RPS B? |
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Definition
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Term
| Which IRMs input to 'A' RMCS? |
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Definition
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Term
| Which IRMs input to 'B' RMCS? |
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Definition
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Term
| Which IRMs' upper range is 9? |
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Definition
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Term
| Which IRMs' upper range is 10? |
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Definition
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Term
| Compare and contrast the design of the IRMs to that of SRMs |
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Definition
| "Both are argon gas-filled titanium ion chambers, coated on the inside with 90% enriched Uranium. Gas pressure for SRM is 14 Atm while for IRM it is 1.2. Detector voltage for SRM is 350 Vdc while IRM is 150 Vdc." |
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Term
| Tech Spec 3.3.1.1 LCO/Applicability and Conditions with less than or equal to one hour completion time |
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Definition
"Section 3.3: Instrumentation; Tech Spec 3.3.1.1 Reactor Protection System (RPS) Instrumentation; LCO 3.3.1.1: The RPS instrumentation for each Function in Table 3.3.1.1-1 shall be OPERABLE; APPLICABILITY: According to Table 3.3.1.1-1; CONDITION C: One ore more Functions with RPS trip capability not maintained. REQUIRED ACTION C.1: Restore RPS trip capability; COMPLETION TIME: 1 hour. CONDITION D: Required Action and associated Completion Time of Condition (A, B,) or C not met. REQUIRED ACTION D.1: Enter the Condition referenced in Table 3.3.1.1-1 for the Channel. COMPLETION TIME: Immediately. NOTE: for IRMs, the two steps referenced in the table are 'G' and 'H'. REQUIRED ACTION G.1: Be in MODE 3; COMPLETION TIME: 12 hours. REQUIRED ACTION H.1: Initiate action to fully insert all insertable control rods in core cells containing one or more fuel assemblies. COMPLETION TIME: Immediately." |
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Term
| TRM 3.3.2.1 LCO/Applicability and Conditions with less than or equal to one hour completion time |
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Definition
"Section 3.3: Instrumentation. TRM 3.3.2.1: Control Rod Block Instrumentation. TLCO 3.3.2.1: The control rod block instrumentation for each Function in Table 3.3.2.1-1 shall be OPERABLE. CONDITION B: --NOTE-- Only applicable to Functions 1,2 and 3 (SRMs, IRM, and APRMs). One or more functions with two required channels inoperable. REQUIRED ACTION B.1: Place channel in the tripped condition OR B.2 Suspend control rod withdrawal. BOTH COMPLETION TIMES: IMMEDIATELY. CONDITION C: One or more required functions with 4 channels inoperable. REQUIRED ACTION C.1 Place channel in the tripped condition. OR C.2 Suspend control rod withdrawal. BOTH COMPLETION TIMES are IMMEDIATELY." |
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