From the conclusions of the OECD Nuclear Energy Agency’s report on spent fuel pool loss-of-coolant accidents:
All SFPs [spent fuel pools] are large robust monolithic structures. The pool walls are generally made of more than one metre thick steel lined concrete. Fuel assemblies are stored in racks that provide spacing for coolant flow and in some cases also for criticality control. The pools are filled with several additional metres of water above the spent fuel to provide biological shielding. An active cooling and purification system maintains optimal conditions for the stored fuel.
The possibilities of loss of cooling and loss of coolant accidents are accounted for in the basic design of all SFPs. The cooling systems have built in redundancies and are connected to emergency backup power to maintain their function. Pool penetrations are kept to a minimum. The cooling systems either have siphon breakers or the depth of the inlet and outlet pipes are limited to prevent draining of the pool. The large volume of water provides a significant thermal mass, which slows the accident progression and gives respite for operator intervention.
Following the Fukushima Daiichi accident, additional measures have been undertaken to improve SFP safety even further. These measures differ greatly due to the large variation on designs, but can be generally stated as improvements in accident response procedures, additional backup electricity or water supplies, and instrumentation improvements.
Humans and other animals across the world die from taking in poisonous radioactive isotopes. High levels of ionising radiation cause so much cell damage (modifications of complex chemistry process, DNA and RNA damage) that the persons get sick (nausea, digestion falters, hair loss) and then die over days or weeks.
I don’t think an environmental radioisotope release can realistically give people across the world acute radiation syndrome.
moving nuclear fuel stored in pools into dry casket storage
The extent to which we can do this is limited because spent fuel must be stored for one to ten years in spent fuel pools while the shorter-lived isotopes decay before it’s ready to be moved to dry cask storage.
But it took “numerous extraordinary actions” to prevent bad stuff from happening with spent fuel at Fukushima-Daiichi until “the alternative cooling system could be installed.” (p. 140). Even with additional safeguards, they seem fairly dependent on power to operate active cooling systems. I think it’s fair to doubt that similar extraordinary actions could be undertaken and sustained if most of the spent fuel pods in the world were experiencing similar situations during a time that the grid was down across much of the world.
The quotes from the OECD Nuclear Energy Agency’s report were interesting.
moving nuclear fuel stored in pools into dry casket storage
The extent to which we can do this is limited because spent fuel must be stored for one to ten years in spent fuel pools while the shorter-lived isotopes decay before it’s ready to be moved to dry cask storage.
I did not know this. I added an edit to the post: “nuclear waste already stored in pools for 5 years”.
I don’t think an environmental radioisotope release can realistically give people across the world acute radiation syndrome.
Can you cite evidence and/or reasoning?
Considering intake of the radioactive isotopes (through skin contact, breathing, and water/food consumption) as well?
This feels like the kinda thing where modelling error can happen easily. I share some of your skepticism here, but also am an amateur in this area.
I don’t have anything to cite, but everything i’ve read about real or hypothetical major nuclear accidents affecting large areas talks about harms like increased cancer risk over the course of years. Dying within days or weeks as described in the original post requires orders of magnitude higher doses of radiation in a shorter time. I don’t think it’s possible to get those kinds of doses from the amount of radioactive material that can realistically be dispersed kilometers away from the accident. (Being concerned about loss of safely usable land for living and farming is reasonable and i’m only complaining about this point because you specifically described acute radiation syndrome.)
From the conclusions of the OECD Nuclear Energy Agency’s report on spent fuel pool loss-of-coolant accidents:
All SFPs [spent fuel pools] are large robust monolithic structures. The pool walls are generally made of more than one metre thick steel lined concrete. Fuel assemblies are stored in racks that provide spacing for coolant flow and in some cases also for criticality control. The pools are filled with several additional metres of water above the spent fuel to provide biological shielding. An active cooling and purification system maintains optimal conditions for the stored fuel.
The possibilities of loss of cooling and loss of coolant accidents are accounted for in the basic design of all SFPs. The cooling systems have built in redundancies and are connected to emergency backup power to maintain their function. Pool penetrations are kept to a minimum. The cooling systems either have siphon breakers or the depth of the inlet and outlet pipes are limited to prevent draining of the pool. The large volume of water provides a significant thermal mass, which slows the accident progression and gives respite for operator intervention.
Following the Fukushima Daiichi accident, additional measures have been undertaken to improve SFP safety even further. These measures differ greatly due to the large variation on designs, but can be generally stated as improvements in accident response procedures, additional backup electricity or water supplies, and instrumentation improvements.
I don’t think an environmental radioisotope release can realistically give people across the world acute radiation syndrome.
The extent to which we can do this is limited because spent fuel must be stored for one to ten years in spent fuel pools while the shorter-lived isotopes decay before it’s ready to be moved to dry cask storage.
But it took “numerous extraordinary actions” to prevent bad stuff from happening with spent fuel at Fukushima-Daiichi until “the alternative cooling system could be installed.” (p. 140). Even with additional safeguards, they seem fairly dependent on power to operate active cooling systems. I think it’s fair to doubt that similar extraordinary actions could be undertaken and sustained if most of the spent fuel pods in the world were experiencing similar situations during a time that the grid was down across much of the world.
The quotes from the OECD Nuclear Energy Agency’s report were interesting.
I did not know this. I added an edit to the post: “nuclear waste already stored in pools for 5 years”.
Can you cite evidence and/or reasoning? Considering intake of the radioactive isotopes (through skin contact, breathing, and water/food consumption) as well? This feels like the kinda thing where modelling error can happen easily. I share some of your skepticism here, but also am an amateur in this area.
I don’t have anything to cite, but everything i’ve read about real or hypothetical major nuclear accidents affecting large areas talks about harms like increased cancer risk over the course of years. Dying within days or weeks as described in the original post requires orders of magnitude higher doses of radiation in a shorter time. I don’t think it’s possible to get those kinds of doses from the amount of radioactive material that can realistically be dispersed kilometers away from the accident. (Being concerned about loss of safely usable land for living and farming is reasonable and i’m only complaining about this point because you specifically described acute radiation syndrome.)