Reactor Coolant System Flashcards

Question

Discuss Reactor Coolant Gas Vent System (RCGVS) System Alarms.

Answer 1

Alarms on high pressure (>2000 psia) – Indicates solenoid isolation valve is leaking Alarm can be reversed to indicate failure of outer seal.

Answer 2

Designed to prevent brittle fracture. Receives input from PZR pressure and TCold. Opens associated PORV if pressure setpoint is reached Unit 1: 530 psia all less than or equal to 300°F (TS limit) 350 psia any less than or equal to 200°F (TS limit) Unit 2: 490 psia less than or equal to 240°F (during a cooldown) 490 psia less than or equal to 252°F (during a heatup)

Answer 3

Required to be met in at least one loop in order to maintain NC flow * Loop Delta T < full power Delta T (50F) * Tcold stable or decreasing * Thot stable or decreasing * Thot & CET’s approximately equal * Subcooling based on CET’s >20F

Answer 4

Sample Isolation Valves close on CIS [CIAS] – can be overridden to open valves: * ‘A’ Hot Leg * PZR Steam Space * PZR Surge Line

Answer 5

Letdown AUTO isolates, Lpzr decreases at 4 gpm (1%/12 min) from RCP seal leak off No means to borate/dilute, No coolant purification ability

Answer 6

Lpzr increases due to CHG pump running Cycle CHG pump to maintain Lpzr Limited ability to borate/dilute, No coolant purification ability

Answer 7

RCS Water level less than the RX Flange (36’), but above 33’

Answer 8

RCS Water level is ≤ 33’ to 31’ 3”

Answer 9

* Water level below Top of Hot Leg; Top of Hot Leg = 31’ 3”; Centerline of Hot Leg = 29’6”; * Use 2 LPSI Pumps with Flow Reduced to 1800 [1500] GPM per pump when on SDC in this condition to avoid vortexing. Vortex Formation is caused by Air Entrainment into the suction of the LPSI Pumps while on SDC due to lowering RCS level < 29’8” * Remove SG manway and install SG nozzle dams between {29’9.5” and 30’}[29’11.4”-29’8.2”] * To prevent RCS pressurization and loss of inventory on loss of SDC, hot legs opened before cold legs = Th manways off first/on last and Tc nozzle dams in first/out last

Answer 10

Limits and Precautions include, but are not limited to, the following: * Do NOT attempt to vent if the RCS temperature is above 200°F. * Fill water shall have a boron concentration equal to or greater than that required to maintain Shutdown Margin in accordance with 1[2]-NOP-100.04, Surveillance Requirements for Shutdown Margin, Modes 2, 3, 4 and 5 * Placing Seal Injection in service to an uncoupled Reactor Coolant Pump may result in significant seal damage. * Seal Injection is required to be in service when filling the RCS from below the Seal Cartridge to above the Seal Cartridge to prevent contaminants on the surface of the Reactor Vessel water from entering the seals. * When the RCS is in Solid Pressure Control, Then close scrutiny should be given to any action that could result in the de-energizing any portion of the Class 1E 125V DC System. This could cause both isolation of the RCS while solid and the simultaneous failure of one PORV, thereby challenging the LTOP single failure design criteria.

Answer 11

Limits and Precautions include, but are not limited to, the following: * When RCS level is being lowered below 30% in the Pzr, BOTH of the following independent level indications shall be operable: The tygon hose & LI-1117-1 * When venting through the RCGVS, the maximum drain down rate is limited to 500 gpm due to 7/16” orifices installed in the vent lines from the Reactor Head and the Pressurizer. * If there is evidence of leaking fuel rods or if recommended by Chemistry Department, the RCS should be drained to the Hold-up Tanks. * RCS drain down should be stopped based on the lowest indicated level. * If the tygon level hose is being monitored by remote video indication and the video signal is lost or the indication is obstructed, the drain down shall be stopped until monitoring of the tygon hose is restored.

Answer 12

Exceeding the TS DT requires Documentation & Tracking Unit 1 350F DT per TR 13.4.1 Unit 2 200F DT per 2-GOP-504 P&L

Answer 13

Identified LEAKAGE 1. LEAKAGE, such as that from pump seals or valve packing (except reactor coolant pump (RCP) seal water injection or leakoff), that is captured and conducted to collection systems or a sump or collecting tank; 2. LEAKAGE into the containment atmosphere from sources that are both specifically located and known to not interfere with the operation of leakage detection systems; or 3. Reactor Coolant System (RCS) LEAKAGE through a steam generator to the Secondary System (primary to secondary LEAKAGE);

Answer 14

Unidentified LEAKAGE All LEAKAGE (except RCP seal water injection or leakoff) that is not identified LEAKAGE

Answer 15

Pressure Boundary LEAKAGE LEAKAGE (except primary to secondary LEAKAGE) through a fault in an RCS component body, pipe wall, or vessel wall. LEAKAGE past seals, packing, and gaskets is not pressure boundary LEAKAGE.