Have they located the melted fuel at Fukushima?

[Astronuc]

And?

If nuclear industry failed to foresee and prepare for the probabilistically likely events, it should AT LEAST fix those deficiencies which now DEFINITELY known to exist (the "hindsight").

And at the time of the Fukushima event, US utilities had emergency meetings to assess their own sites and their emergency preparedness programs - even before the NRC made any statement. US BWRs had already installed safety features not present in the Japanese reactors. Combined natural events were reviewed and reassessed. SAMGs were reviewed.

Which says to me that NPPs *elsewhere* can be in the same situation: underestimating flooding hazards. (Calhoun? Blayais? Rings any bells?)

Calhoun came through that flooding fairly well. It was in a refueling outage, and is still down.
http://www.nrc.gov/info-finder/reactor/fcs/special-oversight.html

I was thinking exactly the same thing wrt Chernobyl.
I'm not so sure about that now. Because...

...people tend to think like this.

LWR operators simply assume Chernobyl will not happen to them, because they don't operate like that, and LWRs don't have graphite moderation. LWRs in flood prone areas are required to assess the flooding potential and have prevention and mitigation plans.

"We physically can't have Fukushima scenario, let's write a report that 'we studied out accident preparedness and we are fine'".

Somehow, I'm not buying it. I would rather read "we bought two more fire trucks and two mobile diesel generators and situated them in two different locations close to plant, and we drill our operators in using them every time we have a refueling outage. Because, although we aren't susceptible to tsunamis, we aren't arrogant a-holes and we think we might be failing to anticipate a possible disaster scenario, Oh, and BTW, we installed four more 100-ton tanks with fresh water on the NPP premises, and stockpiled flexible hoses. Just in case."

Folks have planned to prevent that.

 

[Hiddencamper]

And?

If nuclear industry failed to foresee and prepare for the probabilistically likely events, it should AT LEAST fix those deficiencies which now DEFINITELY known to exist (the "hindsight").
Which says to me that NPPs *elsewhere* can be in the same situation: underestimating flooding hazards. (Calhoun? Blayais? Rings any bells?)
I was thinking exactly the same thing wrt Chernobyl.
I'm not so sure about that now. Because...
...people tend to think like this.

"We physically can't have Fukushima scenario, let's write a report that 'we studied out accident preparedness and we are fine'".

Somehow, I'm not buying it. I would rather read "we bought two more fire trucks and two mobile diesel generators and situated them in two different locations close to plant, and we drill our operators in using them every time we have a refueling outage. Because, although we aren't susceptible to tsunamis, we aren't arrogant a-holes and we think we might be failing to anticipate a possible disaster scenario, Oh, and BTW, we installed four more 100-ton tanks with fresh water on the NPP premises, and stockpiled flexible hoses. Just in case."

The industry is reassessing their seismic and flooding hazards and seeing if they are deficient as part of post fukushima response. So we ARE actively doing something about it.With Fort Calhoun, the flood was actually below the maximum expected flood for the site still. The problems at Fort Calhoun stemmed from the fact that 2 years before the flood, their flood preparations were deficient. The NRC made them fix it. And as far as I can see, the US regulatory system did a good job of identifying a deficiency and ensuring it was corrected such that the flood was non-eventful. Fort Calhoun's problem now really stems from years of deficiencies, and to understand how they got there, you need to have spoken to people who have gone there to help "Clean up". I think Fort Calhoun basically being told that the NRC does not want OPPD to operate the plant anymore was the right thing.

The whole "we did a report and we are fine" thing is NOT what the US has done. In the US, we purchased millions of dollars of new equipment, built 2 regional response centers that can deploy a full set of portable equipment to any site in the country in less than 24 hours (and all the equipment is regularly tested and kept in like new condition), have reviewed and upgraded our emergency procedures to utilize this equipment, and are developing portable equipment hookups and plans. This is all part of the FLEX initiative, and is also an NRC order, to be able to maintain core cooling and critical safety functions indefinitely, in three phases. The first phase is using only on-site permanent equipment that is available after a Fukushima-like event, the second phase starts 24 hours later, and involves portable equipment on site and off site. The third phase is after 72 hours when "offsite help" is allowed to come in. It's assumed that it takes 72 hours for resupplies of fuel, water, personnel, and other non-portable equipment for critical safety functions to arrive. This is what the US nuclear industry has done. NOBODY has simply said "We looked at it and its ok".

With regards to fire trucks, extra fuel, portable pumps, water, the US already did that after 9/11. But 9/11 only required enough equipment for 1 plant, not both. Many plants are installing more generators and equipment. We are going to be pouring concrete at my plant and building a new section where we can put a new generator, and us engineers are figuring out the power requirements to make sure we are capable of restoring critical safety functions in the event all of our normal generators and equipment fail. Post Fukushima, we've added more portable equipment to that because now we are assuming ALL units on site fail simultaneously. Operators, maintenance personnel, and emergency responders (myself included) are regularly trained on our extensive damage procedures and severe accident guidelines.

This is what the US has been doing, and will continue to be doing over the next several years.

 

[nikkkom]

The whole "we did a report and we are fine" thing is NOT what the US has done. In the US, we purchased millions of dollars of new equipment, built 2 regional response centers that can deploy a full set of portable equipment to any site in the country in less than 24 hours (and all the equipment is regularly tested and kept in like new condition), have reviewed and upgraded our emergency procedures to utilize this equipment, and are developing portable equipment hookups and plans. This is all part of the FLEX initiative, and is also an NRC order, to be able to maintain core cooling and critical safety functions indefinitely, in three phases. The first phase is using only on-site permanent equipment that is available after a Fukushima-like event, the second phase starts 24 hours later, and involves portable equipment on site and off site. The third phase is after 72 hours when "offsite help" is allowed to come in. It's assumed that it takes 72 hours for resupplies of fuel, water, personnel, and other non-portable equipment for critical safety functions to arrive. This is what the US nuclear industry has done. NOBODY has simply said "We looked at it and its ok".

With regards to fire trucks, extra fuel, portable pumps, water, the US already did that after 9/11. But 9/11 only required enough equipment for 1 plant, not both. Many plants are installing more generators and equipment. We are going to be pouring concrete at my plant and building a new section where we can put a new generator, and us engineers are figuring out the power requirements to make sure we are capable of restoring critical safety functions in the event all of our normal generators and equipment fail. Post Fukushima, we've added more portable equipment to that because now we are assuming ALL units on site fail simultaneously. Operators, maintenance personnel, and emergency responders (myself included) are regularly trained on our extensive damage procedures and severe accident guidelines.

Sounds good.