Japan: TEPCO aims to achieve 'cold shutdown' for reactors in 6-9 months

Kyodo News ^ | 04/17/11

[TigerLikesRooster]

TEPCO aims to achieve 'cold shutdown' for reactors in 6-9 months

TOKYO, April 17, Kyodo

Tokyo Electric Power Co. said Sunday that it aims to bring the damaged reactors at the Fukushima Daiichi nuclear power plant to a stable condition known as a ''cold shutdown'' in about six to nine months, while restoring stable cooling to the reactors and spent fuel pools in about three months.

At a news conference in Tokyo, company Chairman Tsunehisa Katsumata announced the utility's schedule ''for the moment'' for bringing the complex in Fukushima Prefecture under control, while offering an apology for the ongoing nuclear crisis.

The utility, known as TEPCO, also said it needs three months to achieve ''steady reduction'' in radiation, and an additional three to six months to control radioactive emissions and curb radiation substantially.

It said it is addressing the immediate challenges of preventing hydrogen explosions at the Nos. 1 to 3 reactors and emission of water contaminated with high-level radiation from the No. 2 reactor.

It also said it will put special covers on the heavily damaged buildings of the Nos. 1, 3 and 4 reactors.

[AmericanInTokyo]

I don’t know if anyone really thinks that is a realistic time frame...so this will more than likely be a first iteration.

[chimera]

Seems pessimistic to me. This is a common way of bounding the worst-case of an unknown situation. Remember we heard things like the Deepwater Horizon spill was going to be an "Extinction-Level Event". The Gulf was still there, last I heard. When Saddam blew up Kuwait's oil fields when we kicked him out after the first Gulf War, those fires were going to burn for "decades". They were all out within a year and the fields were back in production.

The major problem right now is to establish some kind of closed-loop cooling on the three reactors and one SFP. That will get away from this once-through cooling they are doing now that keeps flushing effluents out and causing the problems with handling and disposal. But its a conundrum because to get loop cooling you need to get in there and do some plumbing to connect the lines, which is difficult when you have high dose rate effluents being pumped out.

[gandalftb]

Controlled cold shutdowns usually take 2 years. My guess they’ll be close to that or more.

[sefarkas]

God help the plant you two work at if you excuse your ignorance of Technical Specifications and announce to the NRC inspector on-site that you achieved MODE 4 because you were under 212DEGF instead of the required 200DEGF. gandalftb: the reactor system is in thermodynamic equilibrium if it is venting steam and maintaining a constant temperature and pressure. BVW: stay behind your key board and stay away from nuclear power plants were your presence would lead to a regulatory driven shutdown. I'll take five arrogant engineers who know what they are doing long before a house-full of under-educated liberal arts, business major, or whatever romper-room-degree weenies like you two.

[bvw]

Your soup of malevolent assumptions about others has finished cooking your own integrity here to the quick. Way over 150 degrees of superheat.

You are a dangerous idiot, and I am kind to say that.

[sefarkas]

Alarmists like you need to apply to the Union of Concerned Scientists. Writing a letter to your secret pal Ed Markey would also go a long way in stoking unnecessary concern amongst folks trying to understand second and third hand reports on work at Fukushima.

[bvw]

I suggest simple materials handling solutions that move the spent fuel, that not in the immediate process of being unloaded, off too a more secure part of the facility.

For a hundred or so years we have been moving material in devices like this. We surely can build a transport for very hot rad waste.

[bvw]

You don’t know what you are doing. Fwtw. That was obvious in your first post.

[chimera]

The inventory of fission products in lightly-decayed fuel makes handling outside of the vessel, transfer canal, and SFP problematic.

Some plants in this country, owing to a lack of centralized storage (Yucca Mountain) have gone to dry-cask storage, but that is only for heavily-decayed fuel assemblies, on the order of years of decay time to reduce the heat load.

The SFP in Fukushima 4 had a full core that was unloaded in early December 2010. If it had any kind of power history on it, it's unlikely that could go anywhere else other than a SFP. I read somewhere that there were other used fuel assemblies in the pool was well, but I have no details on their power and decay history. If some of those were decayed enough, they could have been candidates for removal to the common SPF that is a feature of the Fukushima Daiichi site. If nothing else, I am guessing we'll see some kind of rule making from the Japanese regulatory authority concerning moving significantly-decayed assemblies from the unit SPF to the common SPF.

That won't let them off the hook regarding beefed up reliability of onsite AC power. No matter where the fuel is, you still have to have some measure of heat removal capability until dry storage is possible.

[bvw]

I’m suggesting that a used fuel storage technology jump is now ripe. Problems are opportunities. In abstract the technology of today is there to do the job, and lacks only a number of earnest competing efforts to make the jump in actual practice.

But these are — like the Carter years — chicken little times. Good that the Japanese have this problem, because they, as a culture, are not chicken littles.

[chimera]

Well, it's interesting, we're probably not talking about a lot of high-tech - basically shielding - although maybe some of these newer ceramic materials would have a role to play. They have high strength and good temperature compatibility. If their shielding power could be beefed up, who knows, maybe some kind of transport vessel with active internal cooling for the trip from the SPF to some other holding facility, might be in the realm of possibility.

Ultimately you'd like to get it to some centralized repository, maybe monitored retrievable storage, and eventually reprocessing. The Japanese do reprocess their used fuel. They do some on their own and also send some to the French facility at La Hague. But it's a slow process for approvals.

Maybe that's the best place to start. Streamline the useless regulations that are holding up the show on reprocessing...?