Primary Containment (T23) Flashcards
What are the PCIS Group 1 isolation signals?
What Valves are affected?
x3 Low’s, x3 Hi’s
Low RWL -101”
Low Cond Vac 10” Hg
Low MS Line Press 855 (850) in RUN
Hi MS Line Flow 169 (136) psid
Hi Temp Steam Tunnel 190 (185) °F
Hi Temp Turbine Bldg 196 (187) °F
Valves:
B21-F022A-D (inbd) B21-F028A-D (outbd) (MSIVs)
B21-F016/19 (MSL Drains)
B31-F019/20 (Rx Wtr Sample)
3x Normal MSL rad – isolates small bore pipe
(Setpoint raised upscale @ > 20%)
3x Normal affects B31-F019/20, MVP and SPE
What are the PCIS Group 2 isolation signals?
What major systems are affected?
RWL Low + 3”
Drywell High Pressure 1.85 psig
R/B Exh Rad High (R609) 18mr/hr*
R/F Exh Rad High (R611) 18mr/hr*
(R634) 6.9mr/hr*
(R635) 5.7mr/hr *
Drywell Rad High 138 R/hr **
**Isolates D/W & Torus 18” V&P Vlvs ONLY
Major systems: DW & Torus V & P (2” CAD & 18”) DW Floor/Equip Drn H2O2 Analyzer TIP Withdraw FP Monitor RHR F040/F049 1/2E11-F015
What are the PCIS Group 3 isolation signals?
What system/valves are affected?
SELF
Steam Line Press HPCI Lo 134(128) #
Exhaust Diaphragm Press Hi 10 #
Leak Detection
HPCI Area Air Temp 165°F
HPCI Pipe Pen Rm 165°F
Torus Temp 165°F 14(13.5) min TD
Torus ΔT 36°F 14(15) min TD
Flow HPCI Steam Hi 303%
+202 (218)” H20 d/p
-100 H20 d/p
HPCI
E41-F002/3 (Steam Supply)
E41-F041/42 (Torus Suction valves)
What are the PCIS Group 4 isolation signals?
What system/valves are affected?
SELF
Steam Line Press RCIC Lo 95 #
Exhaust Diaphragm Press Hi 10 #
Leak Detection
RCIC Area Air Temp 165°F
Torus Temp 165°F 29(28.5) min TD
Torus ΔT 36°F 29(28.5) min TD
Flow RCIC Steam Hi 307%
+143 (199/173)” H20 d/p
-100” H20 d/p
RCIC
E51-F007/8 (Steam Supply)
What are the PCIS Group 5 isolation signals?
What system/valves are affected?
RWCU
G31-F001/4
RWL Low Low -35”
RWCU Differential Flow Hi 56 gpm for 42.5 s
Room High Temp 140°F
Pump Room
Hx Room
CUPS Room
Room ΔT
Pump Room 60°F
Hx Room 60°F (45°F)
CUPS Room 60°F (40°F)
G31-F004 ONLY
NRHX Outlet Temp Hi 140°F
SBLC Actuation (from MCR)
What are the PCIS Group 6 isolation signals?
What system/valves are affected?
RWL Low + 3”
RPV Pressure >138 psig
RHR in SDC
E11-F008/9 (RHR Shutdown Cooling Suct Vlvs)
What is the purpose of primary containment and what exposure limits does it provide for?
Contains radioactive material in a controlled volume and, in conjunction w/ ECCS, prevent exceeding rad exposure limits of 10-CFR-100 for a postulated LOCA (25 Rem WB, 300 Rem thyroid, w/in 2 hrs in exclusion area & entire accident w/in 5 miles)
*Not sure that 10-CFR-100 is the correct document, pretty sure that it is 10-CFR-50.67
What are the internal/external pressure limits for the Drywell?
What are the Temperature limits?
What is the T.S. limit for DW temperature?
Internal press – 56 # External press – 2 #
Temp – 340°F (281°F)
T.S./EOP DW Temp ≤ 150°F in Modes 1, 2 and 3
Where is the sacrificial shield located? What is its purpose?
Inside the Drywell
“Sacrificial” shield protects portions of DW space from excessive rad exposure during ops
During S/D, sacrificial shield provides shielding from Rx vessel radiation for personnel
Where is the biological shield located? What is its purpose?
Outside the Drywell
Concrete serves as primary radiological “biological” shielding for personnel in Rx Bldg
Limits to 2.5 mr/hr
What is the min/max water level in the Torus for normal operations?
T.S. 3.6.2.2
Min ≥146”
Max ≤150”
Mode 1 2 & 3
LCO
Torus Water Level shall be ≥ 146 in and ≤ 150 in
Conditions
A. Water Lvl not in limits - Restore to limits in 2 hrs
B. Not Met Mode 3 in 12 & Mode 4 in 36
What are the Torus Temperature limits? What modes are they applicable for?
Torus Temp Limitations Mode 1,2,3 & >Rng 7 IRM:
95° F: Enter Abnormal procedures and initiate torus cooling
100°F: Place both loops of torus cooling in service & enter TS LCO
105°F: Suspend all RCIC/HPCI testing, enter TS LCO
110°F: Scram reactor IMMEDIATLEY & enter TS LCO
120°F: Depressurize the reactor vessel to < 200 psig.
What is the purpose behind inerting the Drywell with Nitrogen?
Inerting primary containment with N2 lowers the O2 levels in the containment atmosphere so that an EXPLOSIVE mixture is not reached when H2 is produced during LOCA conditions.
What are the Leakage Limits?
Pressure Boundary None
Unidentified ≤ 5 gpm
Total ≤ 30 gpm
Unidentified increase within previous 24 hours ≤ 2 gpm
What is the difference between the Drywell Equipment Drain Sump and the Drywell Floor Drain sump?
Drywell Equipment Drain Sump (DWEDS) - collects water from identified or known sources (hard piped equipment drains)
Drywell Floor Drain Sump (DWFDS) - collects water from unknown or unidentified sources (floor drains)
What is the purpose of the Rx Building/Torus Vacuum breakers? How many of them are there?
2 lines (w/ 2 valves in series) - run from Rx Bldg atmosphere to air space inside Torus – each line provides 100% capacity
First valve (outboard) – self actuating check valve
Second valve (inboard) – air operated butterfly type vacuum breaker (for isolation/testing purposes)
Intended to bleed air from Rx Bldg into Torus
Completely opens w/in 1 second after a 0.5 psid applied across the seat – each line provides 100% capacity
What is the purpose of the Drywell/Torus Vacuum breakers? How many of them are there?
12 vacuum relief valves located inside Torus on continuous vent header w/ a direct flow path into DW – total combined capacity of 133%
Intended to return non-condensable gases from Torus to DW
Completely open w/in 1 second after 0.5 psid applied across the seat.
Self-actuating w/ remote controlled air operator for testing
What signals cause the purge supply valves (307, 308, 309, and 324) and Drywell Torus 18” vents (318, 319, 320 and 326) to isolate?
High Drywell pressure 1.85psig
Low RPV level +3”
Rx Building Hi Radiation 18 mr/hr
Drywell Hi Radiation 138 R/hr
What do the amber lights above the 18” vent valves (307, 308, 309, 318, 319, 320, 324, 326) mean?
Indicate Hi Drywell Radiation at 138 R/hr
What are the major Torus water levels of concern?
57.5” (63”) SRV T-Quenchers uncovered
98” (102”) Downcomer Vent Openings Uncovered
110” (115”) HPCI exhaust vent uncovered
146-150” Technical Specification LCO
193” Bottom of Ring Header (Pressure Suppression capability maintained below this level)
215” (197.5”) Torus to Drywell Vac Bkrs covered
285” Torus spray headers covered
What are the consequences of a failed Torus to DW vacuum breaker?
FAILED OPEN - Containment pressure can exceed 56 psig on DBA LOCA due to loss of suppression capability.
FAILED CLOSED - Containment pressure can exceed external pressure of 2 psid when DW sprays are placed in service (condensation, vacuum effect).
What is the Tech Spec for DW Pressure? Required action and time?
Drywell pressure shall be ≤ 1.75 psig
MODES 1, 2, and 3
A.1 Restore DW pressure to within limit in 1 hour
How do the Drywell Drain Sump Timers work?
Sump pump-out timer, Sump fill timer, Level HI-HI
Timer starts on sump pump activation
If pump still running when timer times out, you get “Drywell Floor/Equipment Drains Sump Leak High”
“Fill timer” starts when pump stops. If pump starts prior to timer expiration, same annunciator alarms.
“Drywell Equip/Floor Drains Sump Lvl High-High” indicates a pump start failure or in-leakage is greater than 100 gpm
The second pump auto starts when High-High alarm comes in
140 F, sumps goes into recirc
How does the TIP system respond to PCIS isolation?
The majority of the time, the TIP system will not be in use; the probe will be IN SHIELD and the ball valve will be closed
If the probe is inserted past the ball valve and it is necessary to isolate the containment (Group 2 signal), the probe must first be withdrawn before the ball valve can be closed
A backup isolation shear valve, for remote manual operation, is provided to ensure isolation in the event that the probes are jammed in the vessel when isolation is required
Confirm leak is in TIP room to actuate the shear valve.
