A Perspective Of The Nuclear Crisis In Japan

A Perspective of the Nuclear “Crisis” in Japan
Alan Waltar
March 23, 2011

Nuclear Builds in Japan
NPP in operation (53) NPP in shutdown (3) Date of Construction start Date of Commercial Operation
SHIKA- 2 HAMAOKA- 5 TOHOKU/ HIGASHIDORI- 1 ONAGAWA- 3

Capacity (10MWe, Gross)
4500 4000 3500

Date of Construction start

Date of Commercial Operation

3000 2500 2000

1500 1000500

TOKAI- 1

KASHIWAZAKIKARIWA- 7 KASHIWAZAKIKARIWA- 6 ONAGAWA- 2 HAMAOKA- 4 SHIKA- 1 KASHIWAZAKIKARIWA- 4 KASHIWAZAKIKARIWA- 3 OHI- 4 OHI- 3 IKATA- 3 GENKAI- 4 GENKAI- 3 TOMARI- 2 TOMARI- 1 SHIMANE- 2 KASHIWAZAKIKARIWA- 2 KASHIWAZAKIKARIWA- 5 HAMAOKA- 3 TSURUGA- 2 SENDAI- 2 FUKUSHIMA II- 4 FUKUSHIMA II- 3 TAKAHAMA- 4 TAKAHAMA- 3 ONAGAWA- 1 FUKUSHIMA II- 2 SENDAI- 1 KASHIWAZAKIKARIWA- 1 IKATA-2 GENKAI- 2 FUKUSHIMA II- 1 HAMAOKA- 2 TOKAI- 2 IKATA- 1 FUKUSHIMA I- 6 OHI- 2 OHI- 1 FUKUSHIMA I- 4 MIHAMA- 3 FUKUSHIMA I- 5 HAMAOKA- 1 GENKAI- 1 TAKAHAMA- 2 FUKUSHIMA I- 3 TAKAHAMA- 1 SHIMANE- 1 FUKUSHIMA I- 2 MIHAMA- 2 MIHAMA- 1 FUKUSHIMA I- 1 TSURUGA- 1

1960

1965

1970

1975

1980

1985

1990

1995

2000

2005

1998.03 TOKAI-1 Shutdown

2

2

Fukushima DaiichiNuclear Plant Event Summary and FPL/DAEC Actions

Fukushima Daiichi Nuclear Station
• Six BWR units at the Fukushima Nuclear Station:
– – – – – – Unit 1: 439 MWe BWR, 1971 (unit was in operation prior to event) Unit 2: 760 MWe BWR, 1974 (unit was in operation prior to event) Unit 3: 760 MWe BWR, 1976 (unit was in operation prior to event) Unit 4: 760 MWe BWR, 1978 (unit was in outage prior toevent) Unit 5: 760 MWe BWR, 1978 (unit was in outage prior to event) Unit 6: 1067 MWe BWR, 1979 (unit was in outage prior to event)

Unit 1

4

4

Fukushima Daiichi Unit 1
• Typical BWR 3 and 4 Reactor Design • Some similarities to Duane Arnold Energy Center

5

5

Fukushima Daiichi Unit 1

6

6

Fukushima Daiichi Unit 1

7

7

Event Initiation
• The Fukushimanuclear facilities were damaged in a magnitude 8.9 earthquake on March 11 (Japan time), centered offshore of the Sendai region, which contains the capital Tokyo.
– Plant designed for magnitude 8.2 earthquake. An 8.9 magnitude quake is 7 times in greater in magnitude.

• Serious secondary effects followed including a significant tsunami, significant aftershocks and a major fire at a fossil fuelinstallation.

8

8

Initial Response
• Nuclear reactors were shutdown automatically. Within seconds the control rods were inserted into core and nuclear chain reaction stopped. • Cooling systems were placed in operation to remove the residual heat. The residual heat load is about 3% of the heat load under normal operating conditions. • Earthquake resulted in the loss of offsite power which isthe normal supply to plant. • Emergency Diesel Generators started and powered station emergency cooling systems. • One hour later, the station was struck by the tsunami. The tsunami was larger than what the plant was designed for. The tsunami took out all multiple sets of the backup Emergency Diesel generators. • Reactor operators were able to utilize emergency battery power to provide power forcooling the core for 8 hours. • Operators followed abnormal operating procedures and emergency operating procedures.

9

9

Loss of Makeup
• Offsite power could not be restored and delays occurred obtaining and connecting portable generators. • After the batteries ran out, residual heat could not be carried away any more. • Reactor temperatures increased and water levels in the reactordecreased, eventually uncovering and overheating the core. • Hydrogen was produced from metal-water reactions in the reactor. • Operators vented the reactor to relieve steam pressure - energy (and hydrogen) was released into the primary containment (drywell) causing primary containment temperatures and pressures to increase. • Operators took actions to vent the primary containment to control...