Fukushima Japan Earthquake: nuclear plants Fukushima part 2

[Sean Thornock]

Can someone on this forum answer the questions regarding the Cobalt-60 / Manganese-54 activation via neutrons and what this means ?

My friend from Argonne told me to look toward these things. What do you think ?

 

[Hiddencamper]

No sir, the doors seal shut by inflatable air that fills a rubber gasket sealing the doors.

When you loss of power, no air, then no water.

And you can say " it's poorly translated " because it contains information you do not like. Is it that crazy for someone to say they seen broken pipes after a huge earthquake. Again, all the reports within the article regarding TEPCO safety history regarding Unit #1 are searchable, and true.

Again, what I'm reading is that an old 2nd hand report from 2011 that contained no specific information is more reliable than a recent official report that not only clearly explains the what where how and why, but also makes sense given my personal experience with the Mark I/II containment design.

Another thing: Do NOT put words in my mouth. Do NOT tell me why I thought something. You are not me. you do not know what I think or why I think something. If you want to know why I think it was poorly translated you can ask. But it is not your job to assert why people do things.

Nothing is crazy with seeing broken pipes. What is crazy is to take "i saw broken pipes" and somehow try to twist that into the ECCS failed, or there was a LOCA, or the reactors were screwed by the earthquake, when there are multiple reports from TEPCO and other agencies that the earthquake caused no appreciable damage to the seismic category I safety systems which are required for reactor shut down.

This forum is not your personal RSS feed. This forum is not a place for you to spread FUD. We do not deal with a lack of respect for science, physics, engineering principles here, nor do the people here care for personal attacks on their beliefs or opinions.

Please do not post here anymore. I know I'm not an admin, but I'm sure one will drop by soon. If you want to actually discuss relevant information about the event we are all willing to help, but when you spam blog posts and do stuff similar to what I see friends of earth/greenpeace and other anti-nuclear groups do on reddit, that's not really acceptable here. Like I said earlier I expect this kind of crap on reddit, not on physics forums.

 

[Astronuc]

I'll let the article stand on its merit. It has more information regarding TEPCO issues in the past regarding those pipes in question. Workers said they seen busted pipes in an article a few months after the disaster. Many of the assertions regarding safety issues are searchable.

The article is rather sensational (full of innuendo, hearsay, and speculation), and thus has little to no merit other than to provide an example of poor journalism.

What about the rubber seals on the SFP doors that inflate with air. Those will not hold air without power. ( fuel pool gate between pool & reactor. Powered by electricity off grid not diesel backups or batteries. ( Hatch/Georgia 1986 lost 141,000 gallons in a few hours time because of this same issue. )

Please provide the source of one's information. One seems to be misinformed. Furthermore, one appears to be speculating in areas with which has no expertise.

I am aware of rubber gaskets (not air filled) in the SFP gates. Please provide the source of information regarding one's assertion that SFP gates have air-filled rubber seals.

I'd like to talk about the Cobalt-60, Manganese-54 ( neutron activation radionuclide / product ) & the large Cesium levels ( wells 1-6 ) pointing toward sfp criticality.

and

Can someone on this forum answer the questions regarding the Cobalt-60 / Manganese-54 activation via neutrons and what this means ?

My friend from Argonne told me to look toward these things. What do you think ?

Co-60 and Mn-54 are activation products from the core. Co-60 arises from neutron capture by Co-59, which is an impurity in stainless steel, or by (n,p) reactions with Ni-60. Mn-54 can be formed by (n,p) reaction with Fe-54, also in stainless steel. These nuclides are found on the surfaces of spent fuel on which corrosion products deposit during operation in a reactor. They are not an indication of SFP criticality.

It was subsequently determined that the spent fuel pools and the spent fuel remained intact following the Fukushima events.

Consequence Study of a Beyond-Design-Basis Earthquake Affecting the Spent Fuel Pool for a U.S. Mark I Boiling Water Reactor, Draft Report, June 2013
http://pbadupws.nrc.gov/docs/ML1313/ML13133A132.pdf

Although the spent fuel pools and the used fuel assemblies stored in the pools remained intact at the plant, . . . .

 

[Astronuc]

I thought those fuel rods were delicate & the radiation levels at unit three are off the charts. Much different then taking wreckage from the roof. The #3 sfp is in very bad shape.

BWR/6 Fuel Assemblies & Control Rod Module ( these can't handle 50 tons without sever damage )

http://www.nucleartourist.com/images/bwrfuel1.jpg

The image describes the configuration of the control blade and four adjacent assemblies that comprise a 'cell' in the core. It is irrelevant to the configuration in the spent fuel pool.

See - last page of http://pbadupws.nrc.gov/docs/ML1125/ML11258A385.pdf.

What do you think about the fault / sandstone below the corium kinda makes it hard to stop the 600 tons of water flowing toward the ocean every day, no ?

As far as we know, the core debris resides in the damaged RPV, or on the floor of the containment building. It is possible that particulate matter resides in the torus and other places where water flowed following the event.

One must distinguish between groundwater flow and flow of contaminated water from the containment and turbine buildings.

 

[Hiddencamper]

With regards to weight/structural capacity of the spent fuel pool racks.

The high capacity spent fuel pool racks that are typical to BWR plants are designed for a faulted load of 35000 PSI in the axial/buckling direction. 50 tons = 100000 pounds, but that mass would be distributed over the entire rack. Given the surface area for that mass to be spread over (at least a few square inches), it is very unlikely that 50 tons would damage the storage rack. With the integrity of the rack ensured, direct fuel damage due to a 50 ton load across the racks would be precluded.

This is out of a BWR USAR (Updated safety analysis report). The USARs can be difficult to find, but are all publicly available in some form through the NRC's ADAMS system or other document requests. Typically Chapter 3 contains information regarding structural/seismic design, and the structural design and loading report for the plant I looked at was where I found this information.

 

[jim hardy]

Wow 35K ? they're even stronger than i thought.

Good info, HC. I'm an instrument guy so always defer to you mechanical gurus on such matters..

Thanks ! old jim

 

[Hiddencamper]

Wow 35K ? they're even stronger than i thought.

Good info, HC. I'm an instrument guy so always defer to you mechanical gurus on such matters..

Thanks ! old jim

I'm an instrument guy too! I just got lucky and found it in our usar while I was looking for some other info

 

[Sotan]

Feb. 25 NHK article regarding the frozen wall project - test phase planned to start March 11:
http://www3.nhk.or.jp/nhkworld/english/news/20140226_03.html

 

[LabratSR]

Report On Fukushima Daiichi NPP Precursor Events

http://www.oecd-nea.org/nsd/docs/2014/cnra-r2014-1.pdf

 

[LabratSR]

Accident Management Insights After The Fukushima Daiichi Accident

http://www.oecd-nea.org/nsd/docs/2014/cnra-r2014-2.pdf

 

[LabratSR]

IAEA - Events and highlights on the progress related to recovery operations at Fukushima Daiichi NPS

http://www.iaea.org/newscenter/news/2014/infcirc_japan0214.pdf

 

[nikkkom]

Accident Management Insights After The Fukushima Daiichi Accident

http://www.oecd-nea.org/nsd/docs/2014/cnra-r2014-2.pdf

71 page of bureaucratic drivel and blisteringly obvious statements of the sort:

"""Low-pressure emergency cooling systems and normal residual heat removal systems typically need power and the availability of the ultimate heat sink. If those are not available, alternative ways to cool the reactor should be used."""

Oh really? Thanks for letting us know that in accidents, reactors need to be cooled by whatever means possible! As if we thought otherwise...

 

[jim hardy]

71 page of bureaucratic drivel

:thumbs:

 

[Astronuc]

71 page of bureaucratic drivel and blisteringly obvious statements of the sort:

"""Low-pressure emergency cooling systems and normal residual heat removal systems typically need power and the availability of the ultimate heat sink. If those are not available, alternative ways to cool the reactor should be used."""

Oh really? Thanks for letting us know that in accidents, reactors need to be cooled by whatever means possible! As if we thought otherwise...

I sympathize with the incredulity expressed.

I , when I read statements like "The TGAM considers as a commendable practice that these actions include (for LWRs and PHWRs) as a minimum1:
• establishment and maintenance of reactivity control in the reactor and in the SFP;
• assurance of availability of heat sink for heat generated in the reactor core and in the SFP;
• control of pressure and water inventory in the primary heat transport system;
• control of pressure and water inventory in secondary heat transport system;
• assurance of containment isolation;
• control of the containment pressure and temperature;
• control of the concentration of hydrogen and other combustible gases;
• control of unfiltered releases of radioactive products;
• control of temperature and water inventory in the SFP."

Commendable? Try mandatory!

"Undergirding these actions is the importance of assuring that electrical power is available . . . " should read "Undergirding these actions is the necessity of assuring that electrical power is available . . . . ".

I wonder if there is a translation problem within the international body.

Core/fuel coolability and reactivity control are abolutely necessary, not just 'nice to have'. The necessities and mandatory nature are spelled out in the General Design Criteria and Standard Review Plans for nuclear systems.

 

[jim hardy]

I sympathize with the incredulity expressed.

Thanks !


Once in a while one reads something that is so obviously profound in its simplicity and logic as to be mind [STRIKE]algering[/STRIKE] altering.
General Design Criteria are that way, and i remember vividly the feelings i had when reading them for the first time ca 1970.

Perhaps the lesson learned is simply "We should have been more rigorous in our adherence to GDC."

But as Parkinson says, every bureaucracy carries an overhead of bureaucrats whose sole function is to read one another's memoranda. (See his "The Law of Delay" , chapter "The Paper Blob" )

If the paper makes industry executives more aware of GDC, and of the machinery they're operating, then it'll do some good.

old jim

 

[Hiddencamper]

Core/fuel coolability and reactivity control are abolutely necessary, not just 'nice to have'. The necessities and mandatory nature are spelled out in the General Design Criteria and Standard Review Plans for nuclear systems.

For example, from the NRC's General Design Criteria (GDC) (http://www.nrc.gov/reading-rm/doc-collections/cfr/part050/part050-appa.html)

Criterion 17—Electric power systems. An onsite electric power system and an offsite electric power system shall be provided to permit functioning of structures, systems, and components important to safety. The safety function for each system (assuming the other system is not functioning) shall be to provide sufficient capacity and capability to assure that (1) specified acceptable fuel design limits and design conditions of the reactor coolant pressure boundary are not exceeded as a result of anticipated operational occurrences and (2) the core is cooled and containment integrity and other vital functions are maintained in the event of postulated accidents.
The onsite electric power supplies, including the batteries, and the onsite electric distribution system, shall have sufficient independence, redundancy, and testability to perform their safety functions assuming a single failure.
Electric power from the transmission network to the onsite electric distribution system shall be supplied by two physically independent circuits (not necessarily on separate rights of way) designed and located so as to minimize to the extent practical the likelihood of their simultaneous failure under operating and postulated accident and environmental conditions. A switchyard common to both circuits is acceptable. Each of these circuits shall be designed to be available in sufficient time following a loss of all onsite alternating current power supplies and the other offsite electric power circuit, to assure that specified acceptable fuel design limits and design conditions of the reactor coolant pressure boundary are not exceeded. One of these circuits shall be designed to be available within a few seconds following a loss-of-coolant accident to assure that core cooling, containment integrity, and other vital safety functions are maintained.
Provisions shall be included to minimize the probability of losing electric power from any of the remaining supplies as a result of, or coincident with, the loss of power generated by the nuclear power unit, the loss of power from the transmission network, or the loss of power from the onsite electric power supplies.

What is interesting with the US's GDCs, is if you find that your plant is not in compliance, you have to restore compliance, regardless of what your license approval said when you built the plant. For example, the 2012 Byron unit trip revealed an electrical power system vulnerability that was present in most/all nuclear power plants in the US (loss of single phase protection). Because Byron was not licensed to that specific event, they did not receive a violation, however all plants now have to restore compliance with GDC 17.

 

[jmelson]

For example, from the NRC's General Design Criteria (GDC) (http://www.nrc.gov/reading-rm/doc-collections/cfr/part050/part050-appa.html)The onsite electric power supplies, including the batteries, and the onsite electric distribution system, shall have sufficient independence, redundancy, and testability to perform their safety functions assuming a single failure.

This seems a mistake. They had, depending on how you count, at least 3 or more
separate failures related to electrical supply. They had transmission lines down, interruption
of and damage to seawater pumps (interrupting both final heat sink for the reactor and most
of the emergency Diesel generators), flooding of electrical panels and generators, and finally
exhaustion of the DC batteries. So, it might be considered they had FOUR separate failures
related to electrical supply before things went totally to hell. That might indicate that these
criteria need to accommodate quite a bit more than a single failure.

Of course, the stupid siting of the plant was what made this a multi-point failure instead of
a manageable single failure. (Sorry, can't stop harping about the site!)

Jon

 

[jim hardy]

The single failure was twenty five feet of seawater.
They were designed to handle what they thought at the time of siting was highest wave possible, around fourteen feet if i remember right.

The geologists who in recent years warned of potential for higher waves sure look good now.
I have to believe had it been brought to executive attention they'd have improved inundation protection.

Good reason to have your diesels high and dry. At the time, thinking was to put them in the basement where earthquakes don't shake them so violently.

I don't know why their diesels were dependent on seawater for cooling. Ours were not.

Tough lessons.

 

[Sotan]

http://www.tepco.co.jp/nu/fukushima-np/handouts/2014/images/handouts_140307_07-j.pdf
(in Japanese, but contains many interesting photos)

It is a report on an inspection of the building of Unit 1.

On Feb 26 a team of 7 people from Tepco and 2 persons from the Nuclear Regulation Authority entered the building of Unit 1, to check for clues on the soundness and earthquake resistance of the building. They planned for a dose of 7.0 mSv of radiation and measured a maximum value of 5.85 mSv on their path. (I am still not confident with these units but that's what they appear to report.)

The did find some damage in the concrete walls and ceilings on the 4th flour and around the elevator shaft, but they say the "shell walls", the spent fuel pool walls and the outer walls at 3rd and 4th floor were found to be basically undamaged. The information will be useful in appreciating the overall earthquake resistance of the building and in planning the further operations on the site.

 

[zapperzero]

(Sorry, can't stop harping about the site!)

Nor should you. The story of the Fukushima failure starts with the anonymous bureaucrat who decided to lower the ground level at the construction site by 20 meters, allegedly to save money on seawater pumps - i.e. before the plant was even fully designed.

 

[Hiddencamper]

External events don't count towards your "Single-Failure" criteria.

When you design a nuclear plant, your plant is supposed to be immune to all external events within the plant's design basis, NOT including the accident initiator OR single failure criteria. Additionally, any equipment that is not qualified for external events is assumed to be failed regardless of the accident initiator or single failure.

So for example, if I have an earthquake, my safety related systems should not fail. The earthquake could cause a loss of offsite power, leading to a load reject, unit trip, loss of feedwater. In this case, the initiating event is the loss of power accident. All my class 1E and seismic category I systems shall be fully capable of performing their safety related function at this point. Then you add in a worst case single failure, which usually is the loss of one of the ultimate heat sink pumps. The loss of a UHS pump leads to a loss of one emergency diesel engine (assuming no air cooled diesels, which is typical of US nuclear plant main diesel generators), and the inability to remove decay heat with that entire train of safety systems. The other redundant qualified systems are still available.

Again, this is in the design of the plant. The real world doesn't always follow design, but the goal of design is to have sufficient barriers such that you can deal with things you get hit with.

Common mode failures are required to be designed out of the plant. Floods, earthquakes, and all external events are not supposed to cause multiple divisions of redundant safety grade equipment to fail, because common mode failures go beyond single failure criteria. Common mode failures are prevented by having appropriate design basis external events (maximum earthquake/flood/missile/etc), as well as ensuring all your safety grade equipment is designed and tested per a nuclear quality assurance program. The NRC and industry's view on common mode failures, is a high quality design and test program, combined with operating history, allow you to rule out common mode failures of components.

Anyways, the black swan here is that everything hinges on how well your external hazards assessment is when you first put together your reactor siting criteria. If you fail to site the plant and assess the hazards correctly, you are at risk of losing multiple trains of safety systems, leading to a plant casualty.

Just my thoughts

 

[nikkkom]

The single failure was twenty five feet of seawater.
They were designed to handle what they thought at the time of siting was highest wave possible, around fourteen feet if i remember right.

The geologists who in recent years warned of potential for higher waves sure look good now.
I have to believe had it been brought to executive attention they'd have improved inundation protection.

I flat out don't believe in this being the case.

In all likelihood management did hear about tsunami studies, but chose to ignore them rather than incur (possibly career-terminating for a particular manager) expenses of building a seawall.

 

[nikkkom]

Nor should you. The story of the Fukushima failure starts with the anonymous bureaucrat who decided to lower the ground level at the construction site by 20 meters, allegedly to save money on seawater pumps - i.e. before the plant was even fully designed.

BTW, did anyone of you hear of any NPP anywhere in the world (other than Japan) which builds or significantly improves its flood protection barriers post Fukushima?

 

[Hiddencamper]

BTW, did anyone of you hear of any NPP anywhere in the world (other than Japan) which builds or significantly improves its flood protection barriers post Fukushima?

Well, we went and reviewed our entire flood analysis. Then we walked down all the flood protection barriers. Found a few that were degraded, but as far as our analysis goes, my plant is not susceptible to external flooding (inland and built above our lake a considerable amount). So we aren't really doing anything different.

I know one plant built a pedestal 15-20 feet above plant elevation, and on it there is a full set of safe shutdown equipment. Two emergency generators, 2 pumps which can be hooked up for UHS/Aux feed.

It really depends on the plant.

honestly I'm more concerned about the dam issue with some plants (oconee)

with regards to "single failure". External effects are technically not "single failure", because it is assumed you will have the external event PLUS a single failure.

 

[jim hardy]

I flat out don't believe in this being the case.

In all likelihood management did hear about tsunami studies, but chose to ignore them rather than incur (possibly career-terminating for a particular manager) expenses of building a seawall.

We can speculate on corporate culture...

in my experience----
i took what i thought was a career risk and apprised our CEO in a hand written note of some vital pumps that just weren't up to snuff considering their importance to safety. He had the complete file on them delivered to him personally, and within six months we had brand new, extremely robust pumps.

call me naive, but i still think it takes integrity to make it to the top. That's why you start there. But you better be doggone sure you're right.

old jim

 

[Most Curious]

At the edge of the current subject:

What were the alternatives to the sea water pumps if all were destroyed or rendered inop? Were any still functional after the "wave?

 

[Hiddencamper]

At the edge of the current subject:

What were the alternatives to the sea water pumps if all were destroyed or rendered inop? Were any still functional after the "wave?

Well...if JUST the seawater pumps were inoperable, Fukushima Daiichi still had air cooled diesel generators. The scenario could have played out like Fukushima Daini or Daiichi units 5/6, which had no UHS for the first couple days. Seawater pumps provide "ultimate heat sink", and without them you are inherently limited on how you can remove heat from the plant.

If you had electrical power but no UHS, one method to make a BWR safe is to feed and bleed the suppression pool and reactor. You would need to use portable pumps or other systems to get water out, and you would have to pump cold water in, until you could establish a UHS. This is challenging though.

Edit: Just to add. A BWR has 2 safety related methods to remove decay heat. The first is to boil water to steam, vent the steam to the suppression pool which acts as a temporary heat sink. Then you cool the suppression pool using your residual heat removal system heat exchangers. Suppression pool water or Condensate Storage System water is then injected to the reactor to make up for the steam vent. This is the method that most plants use when they are > 100 PSI and hot. To cool down, you release more steam than you are generating to the pool.

<100 PSI, you can line the reactor up directly to the residual heat removal system heat exchangers. The heat exchangers are cooled by the ultimate heat sink water system. In this mode, you do not need to inject any water, because you won't need to release any steam.

You can extend how long you can go w/out UHS by injecting outside/cold water directly to the pool and/or reactor, but you'll eventually need UHS to cool down. Most BWRs do not have a method to remove decay heat directly to atmosphere, with the exception of the Isolation Condenser plants (Fukushima unit 1, Oyster creek, dresden, and a few others).

 

[Most Curious]

If I understand correctly then, the plant can be safely cooled for up to 2 days without seawater for UHS.

Is the required UHS cooling requirement then within the capabilities of, say fire trucks, or must larger pumps be rigged?

 

[nikkkom]

> Quote by nikkkom
> BTW, did anyone of you hear of any NPP anywhere in the world
> (other than Japan) which builds or significantly improves its
> flood protection barriers post Fukushima?

Well, we went and reviewed our entire flood analysis. Then we walked down all the flood protection barriers. Found a few that were degraded, but as far as our analysis goes, my plant is not susceptible to external flooding (inland and built above our lake a considerable amount). So we aren't really doing anything different.

I know one plant built a pedestal 15-20 feet above plant elevation, and on it there is a full set of safe shutdown equipment. Two emergency generators, 2 pumps which can be hooked up for UHS/Aux feed.

It really depends on the plant.

My angle is that it's suspicious that no other country upgrades its dams as much as Japan does now.

I find it unlikely that all other countries have excellent flood protection for their NPPs. A picture of sandbagged Fort Calhoun NPP isn't helping to prop up such a notion.

The only other theory why no dam/seawall building is happening is that other countries aren't shocked by Fukushima enough to admit and fix their problems.

How is that filtered vent saga going in US? Still nothing? It's been three years now.

 

[turi]

My angle is that it's suspicious that no other country upgrades its dams as much as Japan does now.

I find it unlikely that all other countries have excellent flood protection for their NPPs. A picture of sandbagged Fort Calhoun NPP isn't helping to prop up such a notion.

The only other theory why no dam/seawall building is happening is that other countries aren't shocked by Fukushima enough to admit and fix their problems.[...]

I don't know much about other countries, but in Switzerland several enhancements have been done, are ongoing or planned after Fukushima. Right now the dam of a hydroelectric power plant upstream of a reactor scheduled for decommissioning in 2019 is being reenforced (a dam break could cause a tsunami like flood). Several external emergency control rooms have been built or enhanced, more mobile generators and water pumps were deployed and better monitoring of spent fuel pools has been installed.