From: Doerflein, Lawrence
Sent: Monday, March 14, 2011 9:51 AM
To: Schoppy, Joseph; Pindale, Stephen; Mangan, Kevin; Balazik, Michael; Orr, Michael; Williams,
Christopher; Brand, Javier; Burket, Elise; Arner, Frank
Subject: Update on Japan – FYI
Being inquisitive and resourceful, you guys may have already researched the web and know this, but the big picture info passed out at the morning meeting was:
One caution – none of this is to be released outside the NRC.
Fukushima Daiichi Nuclear Power Station has six units. Units 4, 5 & 6 were shutdown for maintenance at the time of the earthquake. Unit 1 is a BWR 2 (aka NMPI/OC) and Units 2 and 3 are BWR 3/4s (aka Pilgrim /VY).
The earthquake took out offsite power and caused the 3 units to scram as designed. The 35 ft Tsunami swept away the EDG fuel oil tanks (apparently the design is elevated tanks, not buried) so the site was without power. The isolation condensers cooled Ul for a while until they ran out of water (I guess no makeup available w/o power) and RCIC ran on Units 2&3. RCIC was lost on both units in about five hours; however, a backup battery was obtained / used to keep RCIC running on U2 a while longer (don’t know current status).
Without cooling, there was some core damage in all three units (U2 if not already damaged, will be).
The Zircaloy reaction generated hydrogen which passed through the SRVs to the torus. The primary containment was vented to relieve pressure, and the H2 accumulated in the secondary containment. Again, without power, there was no way to get rid of the H2. Eventually, the H2 ignited on Unit 1 and 3 and took out secondary containment (refuel floor sheet metal structure).
I think it is a matter of time before we see the same thing happen on U2.
All three units have (or will have) core damage (amount unknown), and efforts are geared towards putting water into the reactor vessels. A temporary pit was dug and filled with seawater and boric acid and pumped to the reactor vessels (at least Units 1 &3) using a fire truck. Unfortunately, that source was also lost. Haven’t heard of backup plan.
Last known, the reactor vessels and primary containments were intact on all three units.
Jim Trapp was sent to Japan to follow.
When I hear more, I will pass it on.
- Plant Status of Fukushima Daiichi Nuclear Power Station (as of Sep. 6) (enformable.com)
- All 6 Fukushima Daiichi Reactors and Fukushima Daini nuclear power plant’s likely to be decomissioned (enformable.com)
- Status of Fukushima Daiichi (as of September 20) – Temp Worker knocks filter off mask – no internal contamination found (enformable.com)
- March 12th 2011 12:52 PM FOAI Communication – Reactor 1 Water level was known to be below top of active fuel (enformable.com)
- A view of dust sampling at the upper part of the Reactor Building of Unit 1 at Fukushima Daiichi Nuclear Power Station (pictured on September 11, 2011) (enformable.com)
- New TEPCO Photos of Sampling On-site at Fukushima Daiichi and Accumulated Water in Containment Vessel at Fukushima Daini (enformable.com)
- TEPCO Releases New Before and After Photos Of Stricken Fukushima Daiichi Plant (enformable.com)
- TEPCO Official – Pressure and Temperatures inside of Reactor 1 at Fukushima Daiichi exceeded Design Basis (enformable.com)