Civil Engineering Reference
In-Depth Information
Fig. 9.10
Hydrogen explosions within the reactor auxiliary systems building destroyed the upper
steel structure and the roof [
12
,
13
]
9.3.1 Spent Fuel Pools of the Fukushima Daiichi Units 1-6
9.3.1.1 Unit 1
When the hydrogen detonation occurred and damaged the upper building structure,
material might have been falling into the spent fuel pool. There is, however, no
evidence that the fuel was damaged. A concrete pumping truck was used to provide
makeup water inventory. An alternative cooling water system was put in service
soon afterwards. The cooling water temperature has been maintained
<
35
C[
21
].
9.3.1.2 Unit 2
Using existing piping water addition to the unit 2 spent fuel pool was possible. No
fuel was damaged. A dedicated system using a heat exchanger was put in service
afterwards. The cooling water temperature has been maintained
35
C[
21
].
<
9.3.1.3 Unit 3
After the upper building structure had been destroyed by the hydrogen detonation
water cannons were used for spraying water and helicopters dropped water into the
spent fuel pool of unit 3. Then concrete pumps provided water addition to the spent
fuel pool. The use of existing piping to restore water cooling started soon after-
wards. Photographs showed that parts of the building structures had fallen into the
