Fukushima-Daiichi Nuclear Plant Status Update
1 Apr (NucNet): The following is a summary of the status of all six reactor units and the spent fuel pools (SFPs) at the Fukushima-Daiichi nuclear plant.
Unit Status Summary At Fukushima-Daiichi: 16:00 Japan time, 1 April 2011 (pressures and temperatures 31 March):
Unit 1
Core and fuel integrity: damaged.
Reactor pressure vessel integrity: unknown.
Core cooling requiring AC power: not functional.
Building integrity: severely damaged by hydrogen explosion.
Water level in the rector pressure vessel (RPV): fuel partially or fully exposed.
Pressure of the RPV: now decreasing after initial increase (3–5 bar).
Temperature of the RPV: slight decrease (250 degrees Celsius at feedwater nozzle; 128 degrees Celsius at bottom head).
Water injection to core: continuing. Now using fresh water instead of seawater.
Water injection to containment vessel: to be confirmed.
Containment venting: temporarily stopped.
Unit 2
Core and fuel integrity: severely damaged.
Reactor pressure vessel integrity: damage suspected (suppression chamber).
Core cooling requiring AC power: not functional.
Building integrity: slightly damaged.
Water level in the rector pressure vessel: fuel partially or fully exposed.
Pressure of the RPV: decreasing (0.2 bar).
Temperature of the RPV: slight increase (181 degrees Celsius at feedwater nozzle; unknown at bottom of head).
Water injection to core: continuing. Now using fresh water instead of seawater.
Water injection to containment vessel: to be confirmed.
Containment venting: temporarily stopped.
Unit 3
Core and fuel integrity: damaged.
Reactor pressure vessel integrity: unknown.
Core cooling requiring AC power: not functional.
Building integrity: severely damaged by hydrogen explosion.
Pressure of the RPV: decreasing (0.1–0.2 bar).
Temperature of the RPV: slight increase (89 degrees Celsius at feedwater nozzle; 114 degrees Celsius at bottom of head).
Water injection to core: continuing. Use of fresh water under consideration.
Water injection to containment vessel: to be confirmed.
Containment venting: temporarily stopped.
Unit 4
Shut down at the time of the earthquake, no damage to fuel (which had already been removed from the reactor and transferred to the pool), core or containment. Building integrity severely damaged by hydrogen explosion.
Unit 5
Shut down at the time of the earthquake, no damage to fuel, core or containment. Vent hole opened in roof as precaution against hydrogen explosion. Unit in cold shutdown.
Unit 6
Shut down at the time of the earthquake, no damage to fuel, core or containment. Vent hole opened in roof as precaution against hydrogen explosion. Unit in cold shutdown.
Spent Fuel Pool Status At Fukushima-Daiichi 31 March 2011:
Fuel integrity: unknown at units 1 and 2; possibly damaged at units 3 and 4; safe at units 5 and 6, and in the common spent fuel pool.
Unit 1
Spraying with fresh water began on 31 March.
Unit 2
Water injection carried out periodically since 20 March; switch from seawater to fresh water on 29 March; water temperature 46 degrees Celsius.
Unit 3
Water level low, water injection continues; switch from seawater to fresh water on 29 March.
Unit 4
Water level low, water injection continues; switch from seawater to fresh water on 29 March. Reactor building damaged by explosion and fire on 15 March.
Units 5 & 6
Pool cooling capability recovered.
Common Spent Fuel Pool
Seawater was sprayed over this pool on 21 March. Pool cooling was restarted after successful installation of an external power supply line on
24 March.
More details:
Major Parameters: www.nisa.meti.go.jp/english/
Conditions of Fukushima-Daiichi Nuclear Plant:
Reactor Status and Major Events: www.jaif.or.jp/english
Dan Yurman
Email: dan.yurman@usa.net
Mobile: 208-521-5726
No comments:
Post a Comment