Containment Building Flashcards
What makes up the containment pressure boundary?
The following elements that form the Design Basis Accident (DBA) Containment Pressure Boundary.
- Reinforced Concrete Foundation Mat
- Post-Tensioned Concrete Containment Wall & Dome
- Containment Steel Liner
- Personnel Airlocks (Normal & Emergency)
- Equipment Hatch
- Mechanical Pipe Penetrations
- Electrical Penetrations
- Fuel Transfer Tube
What is the design bases of containment?
The total energy contained in the water of the PCS is released into the containment.
Energy Sources
- NSSS Stored Heat
- Reactor Core Decay Heat
- Metal-Water Reactions
- Hydrogen Combustion
What is the designed leakage limit of containment?
Allow a leak rate of NO MORE than 0.1 weight-percent/day at a design pressure of 55 psig and a design temperature of 283°F.
What are containment pressure and temperature design limits?
Pressure - 55 psig
Temperature - 283°F.
What is containment adminstrative temperature limit?
For MODEs 1, 2, 3 and 4 Containment Temperature administrative limit is ≤ 135.96°F on PPC pt. TE-1815 or 130°F if TI-1815
What is the containment tech spec temperature limit?
TS 3.6.5 limit is 140°F
This temperature is the maximum Containment Average Air Temperature prior to a DBA or Main Steam Line Break (which can cause higher temperature/pressure under certain conditions) to prevent exceeding the design pressure with the resultant Containment Peak Pressure.
What is the containment administrative pressure limit?
Containment Pressure administrative limits for MODEs 1 and 2 < .85 psig, for MODEs 3 and 4 <1.35 psig.
- C-03 Indications
- Containment Building Pressure PI-1805 (1812)
- 0 – 100 psia
- Containment Building Pressure PI-1805 (1812)
- C-13 Indications
- Containment Pressure PIA-1814/1815
- 0 – 5 psig
- Containment Pressure PIA-1814/1815
What is the containment pressure tesch spec limit?
TS 3.6.4 limit for MODEs 1 and 2 ≤ 1.0 psig MODEs 3 and 4 ≤ 1.5 psig.
Pressure limits ensure that in the event of an accident, the maximum Design Pressure of the Containment (55 psig.) is not exceeded
During normal operations, how is containment vented?
Containment pressure is maintained by venting to the stack via CWRT T-64D to Radwaste Exhauster V-14A/B plenum or the VGCH
How is containment humidity controlled?
During normal plant operation, Containment Humidity Control is a function of Containment Temperature Control.
As Containment Temperature rises, Containment Humidity will rise. Conversely, if Containment Temperature lowers, Containment Humidity will lower.
An increase in Containment Humidity is an indication of a release of water vapor. A 10% change in humidity would result in approximate 150 gallons of primary water leakage, independent of leak rate.
How are Containment Isolation Devices (Valves) classified?
Active (automatic) and Passive
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Define active containment isolation devices (valves).
Check valves, or other automatic valves designed to close without operator action following an accident, are considered active devices.
To be Operable
- Valves must have isolation stroke times within limits
- Valves must be able to actuate upon receipt of a CHP or CHR signal.
- Valves must pass a periodic leakage rate test.
Define passive containment isolation devices (valves).
Manual valves and de-activated automatic valves secured in their CLOSED position, blind flanges, and closed systems are considered passive devices.
To be Operable
- Must be closed and locked (manual valves).
- Valves must pass a period leakage rate test
Personnel and emergency hatches as well as the equipment hatch are considered passive devices.
Why do most penetrations have two isolation features in series?
So that no single credible failure or malfunction of an active component can result in a loss of isolation or leakage that exceeds limits assumed in the safety analysis.
- Penetrations that contain only one isolation device are either normally closed during operation or are in service during accident conditions.
What signals isolate containment?
Containment High Pressure (CHP) signal
Containment High Radiation (CHR) signal
Not all containment isolation valves are actuated by both signals
What events result in a release of radioactive material within containment?
- Loss of Coolant Accident (LOCA)
- Main Steam Line Break (MSLB)
- Control rod ejection accident.
Safety analysis assumes that CIVs are either CLOSED or function to close within the required isolation time following event initiation.
Assumes that the purge exhaust and air room supply valves are closed at event initiation.
What specific plant parameters that will cause an automatic containment isolation?
Containment High Pressure, initiates ≥ 3.7 psig ≤ 4.3 psig
Containment High Radiation of 10 R/hr on RIA-1805, 1806, 1807, 1808
Refueling Monitors RIA-2316 and RIA 2317
- Placed in service by placing the Cutout Switches for RIA-2316 & 2317 in the “IN” position using the key switches on panel C‑11A rear.
- T.S. Bases 3.3.6 states monitors typically set 25mr/hr above background
- Currently at 80 mr/hr above background
CHP left channel equipment and relay power supplies.
2/4 logic using Pressure Switches 1801, 1802A, 1803, 1804A.
- ‘A’ switches have two contacts that close > 4 psig
- Others have 1 switch at 3.4 and 1 switch at 4
- Seal in circuit requires containment pressure on 3 of 4 channels < 3 psig to reset.
Power Supply Y-10
CHP right channel equipment and relay power supplies.
2/4 logic using Pressure Switches 1801A, 1802, 1803A, 1804.
- ‘A’ switches have two contacts that close > 4 psig
- Others have 1 switch at 3.4 and 1 switch at 4
- Seal in circuit requires containment pressure on 3 of 4 channels < 3 psig to reset.
Power Supply Y-40
How does a test of CHP occurr and what happens?
Depressing Test Push Button on C-13 for channel being tested
- CHPL-CS (Left Channel
- CHPR-CS (Right Channel)
Depressing the test button causes:
- 5-second delay via TDPU relay
- A block of the automatic opening of spray valves CV-3001 and CV-3002.
- The spray valve test light on the SIS sequencer alarm panel lights. (Panel C-13)
- Initiation of one channel of Containment High Pressure logic (and same side channel of SIAS)
- NO equipment actuation!