April 17, 2011
Oil Industry Macondo Response Lesson For Nukes
In response to the BP Macondo Deepwater Horizon oil well blow-out and resulting 87 days of oil gushing into the Gulf of Mexico 2 consortiums of oil companies and formed 2 companies to develop devices that can be brought on after a blow-out to cap a run-away well within a couple of weeks of a blow-out. 10 major oil companies (e.g. Exxon and COP) that account for 70% of the oil pumped in the Gulf put up $1 billion to fund the Marine Well Containment Company (MWCC) to create what are called capping stacks. Some of these stacks are ready for deployment.
A separate group of oil companies founded Helix Well Containment Group which has developed their own capping stacks. The first Helix design works to 5600 feet, which is deeper than the 5000 feet water depth of the Macondo well. The next Helix capping stack due this summer will be good to 10000 feet. Many of proposed new drilling sites are at 10,000 feet and deeper. MWCC is on a similar path to develop greater well capping capability.
The MWCC interim well containment system is ready for deployment with the capacity to contain up to 60,000 barrels per day of fluid in up to 8,000 feet of water. Work is also under way on the expanded system for delivery in 2012 to handle up to 100,000 barrels per day of fluid in up to 10,000 feet of water.
To my mind this aspect of the oil industry's response to this disaster (develop much better tools for handling worst case scenarios) illustrates what the nuclear power industry needs to do: develop a set of portable capabilities that can be rapidly deployed to any nuclear reactor site to rapidly recover from major systems failures. These capabilities are not a substitute for improvements that reduce the odds of such failures. But industries such as nuclear power and oil extraction should admit their best laid plans (which are often not laid out all that well in the first place) can fail and fail very badly.
I would like to see the nuclear power industry explain how they can develop a number of capabilities including:
Portable reactor cooling systems for cooling system failures.
- Reactor wall patching systems for cases when a reactor breach occurs.
- Portable shielded reactor control centers for when normal control centers become damaged or their radiation levels go too high.
Everything that went wrong at Fukushima should be dealt with by consortia of nuclear power industry companies by developing technologies that can substitute rapidly for damaged systems and do more rapid repair of reactor sites.
Update: The fact that new nuclear reactors can be designed to be less susceptible to the failure mode at Fukushima is a good thing. But it is besides the point for the already existing hundreds of nuclear reactors around the world. Unless those are going to be shut down soon (and with the possible exception of Germany that appears very unlikely) we need better ways to handle failures at reactors already in place. Of course existing reactors can be upgraded (e.g. with cooling pumps that won't get knocked out by a tsunami wave). But if one fails we need better tools to deal with the consequences.
Nobody would even know about the four Fukushima nuclear power plants if they had not been situated at a higher elevation.
The fault lay not in their designs--however obsolete--but in their locations.
If the plants had been situated on Japan's West Coast (i.e. not along the subduction zone) their elevation would not have mattered.
If Tepco had responded to Seismic research about past tsunamis by building pumping stations that could get washed over without damage then again the low elevation would not have led to meltdowns.
It was a solvable problem, even after the plants had been built.
Oh, there were design problems too. Having the emergency water-supply steam turbines also (a) condense the steam and dump the heat outside the building rather than using the water suppression pool as a very limited heat sink, and (b) run generators to recharge the backup batteries would have allowed the reactors to self-cool for much longer, perhaps indefinitely. Sealed, passively-cooled "wet casks" for fuel that's still too hot for dry storage would have dealt with the spent-fuel pools.
"The first Helix design works to 5600 feet, which is deeper than the 5600 feet water depth of the Macondo well. "
Are you sure that 5600 feet is really deeper than 5600? I've got some doubts about that...
If the reactors had been built in a similar way on the west coast then they might have been severely damaged in the 1983 Japan Sea Tsunami as the waves reached 10 meters in some areas.
I just saw this thing on PBS highlighting one of China's new reactors built by GE. It has a gravity fed water cooling system instead of an electric powered water cooling system. Therefore, if there is no power to cool the rods with water, the tank at the top of the cooling tower will drop water down through gravitational force. I think they allowed for 5 days of cooling in that water tank to get the power back on.
There are several Advanced PWR and BWR reactor designs by GE and Westinghouse etc. However the present business and regulatory climate in the US effectively prevent any construction.
Placement is a part of design... What is definitely needed are large industrial robots that are shielded enough to go in and do whatever repairs or mods are needed in the buildings. Because we don't know what designs worldwide will maybe not work well. The packbots and stuff are great for recon, but they can't pull debris out of the way. This is similar to having the correct ROV's for your deepwater oil wells... but for some reason, nobody is doing it.
These advanced designs are all passively cooled and require no power or operation for weeks to keep core intact.
Good idea. Disaster prevention by improved designs is necessary, but not sufficient, since even the best prevention techniques might have a hole somewhere. So they must already have capability in place to deal with any disasters after the fact as well.
In general, the things that would have minimized or eliminated the Japanese reactor problems boil down into Procedures and Design, both of which Nuke reactors have in great abundence. The problem we have hit is which Procedure or Design items contribute to a safe plant, and which ones are just pure drek getting in the way of running the reactor. People have long had tendencies to view procedures as an obstacle instead of a step in an orderly process (Railroad engineers who tie down the steam relief valves, pilots who trust their autopilot enough to work on their laptops, etc...) Anybody who has had to deal with the paperwork involved in a reactor cannot argue we do not have *enough* of the stuff, only that a great deal of it should be reviewed, reduced, and organized better so that high-priority design risks (Tsunami + earthquake) do not wind up being burried under a thousand pages of "how to change a light bulb" instructions.
As a nuclear engineer, the preliminary quickie analysis is that things would have been OK except that the emergency diesel fuel oil storage tanks were located where the tsunami could get them. Once those are gone, the diesels run for maybe an hour on their day tanks and then quit. We have batteries that are designed for 8 hours under such a situation ("station blackout") but once they're gone, it is just a matter of time until core damage.
The plant design did darn well but the inputs from the hydrologists, seismologists, etc underestimated the design inputs. Nature surprised our best efforts just as it did in the earlier earthquake on the West Coast of Japan.
I would note that all the videos of the tsunami hitting cities showed seawalls around their harbors. All those were overwhelmed too.
Fukushima was one small event in a huge natural disaster and NOT an accident. One plant worker died compared to 30,000 dead and missing from the quake and wave.
We in the nuclear industry are all working to understand the sequence of events at Fukushima and devise improvements to our existing and future designs. The pros are working the problem.
The nuke power companies need to start out with intrinsically safe designs - no power needed for cool down. What you suggests - emergency response teams is more or less window dressing. The problem is that a high rad environment is not safe for humans and it destroys machines.
Look at your power profile for a shut down. Roughly 5% to 7% of plant output at shut down. About 1% after a day. Declining to about .5% after a month. It takes about 2 years of cool down before thermal emissions are not a problem. So a 24 hour emergency response team has missed the worst of an accident.
As for "if only the design was stronger in this respect....." Hear about the tornado that shut down a nuke plant in VA a few days ago? The back up generator worked. That time. I don't think a bigger sea wall would have helped in that case. A plant that doesn't need power to cool down is the real requirement.
Of course 200,000 people evacuated permanently from an area is a minor consequence. So minor that TEPCO is technically bankrupt and the Japanese government will be stepping in to cover the company shortfall. Electric rates will be going up in Japan to cover the government shortfall.
When was the last time a power company went tits up from an accident at a coal or gas fired plant?
And why are nuclear plants insured by the government and not private industry?
Portable shielded reactor control centers for when normal control centers become damaged or their radiation levels go too high.
That is a LOT of wiring and plumbing to connect in a high rad environment. Even in a low rad environment it is a lot of work. It is not a plug 'n and play type environment. And plant design is not standard. And of course plant changes must be reflected in changes to the emergency equipment. What if plant A makes a change and a similar plant B does not?
It is all magic unicorns because you are not thinking of the emergency response as a system that must be managed but as a magic bullet.
"The first Helix design works to 5600 feet, which is deeper than the 5000 feet water depth of the Macondo well."
Either you misread the sentence, or the sentence was corrected after you read it.
Window dressing and newer and better plant designs: But the existing plants (over 100 in the US) aren't going way.
24 hour delay for an emergency response team: If 24 hours is too long then response teams and equipment need to be able to get on site faster than that. The US of A is not that big. A C-17 in the middle of the country can get to either coast and land on a rough runway in a few hours. So equipment located near a USAF base could get moved to a reactor probably in 6 hours or less. Make more back-up equipment and site it closer to the nukes and the time could be cut further.
Also, reactors could be upgraded to lengthen the time before they run too low on water. Granted that's an expensive proposition. Some US reactors have 4 hours of back-up battery power and others have 8 hours. Some have some gravity feed back-up water. Others do not. We could reduce the size of the potential problem by moving the spent fuel off-site. But Harry Reid blocked one storage site in Nevada.
Regards the tornado in Virginia: I wonder what a category 5 hurricane would do to a US east coast nuclear reactor.
Emergency response and wiring: I'm not envisioning full restoration of existing control systems. Some of what the replacement system would control would itself be new stuff that gets brought in.
Yes, I corrected the sentence in response to Brett's comment.
It doesn't matter where spent fuel is located as long as it's isolated in some rugged, passively-cooled container. There are all kinds of ways to do this, we just have to pick one and spend the money to implement it. Once implemented it should be fairly cheap, because the containers can be re-used as fuel gets moved into dry casks or off-site entirely.
With something like that for spent fuel, and a "heat pipe" leading to a rooftop cooling tower for the reactor proper (returning condensed steam to the reactor vessel), even the Fukushima Daiichi reactors would have been walk-away safe or close enough as to make the current issues look ho-hum.