HP- Containment Hydrogen Control Flashcards
What is the purpose of the containment hydrogen control system?
Monitors the hydrogen concentrations in the Containment Bldg following a LOCA.
How is hydrogen gas generated inside Containment after a LOCA?
- Metal-water reaction involving the zirconium fuel cladding and the reactor coolant.
- Radiolytic decomposition of the post-LOCA emergency cooling solutions (oxygen also evolves in this process).
- Corrosion of metals and paints by solutions used for emergency cooling or containment spray.
What components is the hydrogen monitoring subsystem composed of?
- Hydrogen Gas Analyzers
o HPA-E02 & HPB-E02 - Containment Isolation Valves
o HPA-UV-1, HPA-UV-3, HPA-UV-5
o HPB-UV-2, HPB-UV-4, HPB-UV-6
What is the purpose of the containment hydrogen monitoring subsystem?
Designed to measure the hydrogen concentrations in Containment from two independent locations during an Emergency Operating Procedures.
During which Emergency Operating Procedures will each unit’s hydrogen monitoring subsystem start to measure hydrogen?
- Loss of Coolant Accident (LOCA)
- Excess Steam Demand (ESD)
- Entry into the Functional Recovery Procedure
Where do the hydrogen analyzers draw and discharge from/to?
They are located in the Aux Bldg
They draw from containment atm and discharge back to containment atm.
How do the hydrogen analyzers operate?
Two redundant train specific analyzers with sensor and electronics that provide an indication of containment hydrogen locally and in the CR.
Normally in standby, place in service by CR, readings take about 30 mins.
What are the gas bottles mounted next to the hydrogen analyzer panels?
- The Span Gas bottle (4% H2 in N2) is required for calibration of the Analyzer.
- The Reagent Gas bottle (100% 02) is required for operation of the Analyzer.
What is the TRM T3.3.105, Post-Accident Monitoring Instrumentation, for the Containment
Hydrogen Monitor?
Two containment hydrogen monitors functional.
What is the purpose of the containment hydrogen control system’s containment isolation valves?
Normally closed to provide Containment isolation. They are opened when placing the Hydrogen Analyzers into service.
How are Inside containment isolation valves operated?
From the CR to align the hydrogen monitoring subsystem for operation following:
LOCA
ESD (Excess Steam Demand)
Direction from Functional Recovery Procedure
What happens to all the hydrogen control system containment isolation valves upone a CIAS?
They close.
What powers the Hydrogen Analyzers and Hydrogen control system containment isolation valves?
PH- Class 480 VAC
What powers the MCC distribution panels to the hydrogen analyzer control panels?
PH-Class 480 MCC provides 120 VAC
What powers the solenoid operated hydrogen analyzer isolation valves?
PK-125 VDC
