So all that ado is about 6 grams of tritium? Not 6 grams / liter of "contaminated" water, but 6 grams total? All I can do is shake my head at the stupidity of anyone who believes that dumping 6 grams of anything in the Pacific Ocean is a problem, much less 6 grams of tritium.
It is difficult to form an opinion when scientific institutions are controlled by the nuclear industry and information is censored. I myself was dismissed from Inserm for the discovery of cancers caused by mammographic screening (Corcos & Bleyer, NEJM, 2020).
This blanket statement is incorrect for workers at heavy water nuclear plants: “The only way tritium can possibly hurt you is if you drink such enormous quantities of tritium containing water that the water itself will be the health problem.”
The levels of tritium in air in some areas of an operating CANDU reactor can be in the thousands of MPCa (DAC), requiring air-supplied plastic suits to prevent large whole body radiation doses from inhaled and absorbed tritiated air. Ten hours unprotected exposure at 4000 MPCa would result in a whole body dose of 100 rem (1000 mSv) and likely acute radiation syndrome.
It is because high levels of tritium can cause acute and long term harm in this occupational setting, that tritium is continuously monitored, protective equipment is always required, and tritium uptake is regularly measured via urine sampling. As a result, no CANDU worker has ever received a tritium dose above the annual regulatory limit (5 rem / 50 mSv).
Thanks qualification. That must be a very confined space with a lot of evaporation. Can you point us to a reference which has the specifics/calculations?
Not a fan of annual limits. Daily limits would be far better. See
In my day, it was commonplace to work in air-supplied plastic suits in the reactor vault with tritium levels of 400 MPCa, which *if unprotected* would be the equivalent of 1 rem/hr (10 mSv/hr). And that’s a huge space — thousands of cubic meters. When air driers are used they can cut the tritium level in half, but when the source is moderator water at 10 Ci/kg, it’s always going to be high MPCa.
This old document gives a description of the dose calculations p.45
But ultimately, it’s only in these extreme, and well-controlled, occupational settings where there’s any substantial risk. I certainly agree with your overall point about the trivial hazard that tritium presents to the public. You’ve done great work pulling together this and also on LNT. 👍👍
Thanks docs. The canteach chapter is well written. Of course, it assumes LNT. Sigh.
This could be dangerous. The pre-1950 limit was 1 mSv per day. Basing the limit on the daily dose roughly matched our rad damage repair period. The current "tighter" worker limit is 20 or 50 mSv/y depending on where you are. It is possible to comply with the current limit and violate the old biology based limit by a factor of 20 or more.
But let me get this straight. You guys went into reactor building containment with the reactor operating? So much for the sensible Canadian stereotype. What were the gamma dose rates?
I’m talking about shutdown work — the tritium hazard remains high throughout a CANDU outage (but not everywhere…when I was at Pt. Lepreau for an inspection in the late 80s, early 90s, the tritium levels were so low that we were able to enter the reactor building without any respiratory protection. Not sure how they managed it.)
But, for most CANDUs, work can be done in the reactor building during operation, where there is adequate “biological shielding”, and nowhere near the reactor face, but it is very unusual and is always treated as high hazard work.
Regarding LNT, in practice the dose rates are also kept alara, and the occupational exposures are kept to no more than 2 rem/yr with other limits specified in the power workers union collective agreement, so I’m not worried so much about cell damage repair in this context. But it sure does drive up the operating cost.
It seems like the obvious solution would be to thoroughly ventilate the reactor building on shutdown. Guessing regs and/or PR considerations prevented this (except possibly at Pt Lepreau?)
Yeah, no way we’d release to the environment, even when there’d be no actual impact. There’s your LNT again…an insignificant dose times millions of people implies calamity.
I like the be prepared to walk mentality. The NRC is still living in 1979 when the relative advantages of nuclear for air quality and low carbon were not really on the agenda
The US government should put out a tender for new nuclear regulations and see what kind of bids come in. The NRC needs to know the government is prepared to walk on them, they just won't create credible advanced nuclear regulations based on their mindsets and incentives
"Another troublesome radionuclide, tritium, with a halflife of 12.5 years, is highly mobile and cannot be effectively captured. Even with a costly off-gas control system, MSRs would almost inevitably discharge far more tritium and other radioisotopes into the environment during normal operation than solid-fueled reactors."
The counter-argument is:
"The solar salt loop captures any tritium that has made it to the secondary loop".
So all that ado is about 6 grams of tritium? Not 6 grams / liter of "contaminated" water, but 6 grams total? All I can do is shake my head at the stupidity of anyone who believes that dumping 6 grams of anything in the Pacific Ocean is a problem, much less 6 grams of tritium.
The solution to pollution is dilution!
It is difficult to form an opinion when scientific institutions are controlled by the nuclear industry and information is censored. I myself was dismissed from Inserm for the discovery of cancers caused by mammographic screening (Corcos & Bleyer, NEJM, 2020).
https://danielcorcos.substack.com/p/bca
More on the subject:
https://twitter.com/daniel_corcos/status/1616796601648914432
This blanket statement is incorrect for workers at heavy water nuclear plants: “The only way tritium can possibly hurt you is if you drink such enormous quantities of tritium containing water that the water itself will be the health problem.”
The levels of tritium in air in some areas of an operating CANDU reactor can be in the thousands of MPCa (DAC), requiring air-supplied plastic suits to prevent large whole body radiation doses from inhaled and absorbed tritiated air. Ten hours unprotected exposure at 4000 MPCa would result in a whole body dose of 100 rem (1000 mSv) and likely acute radiation syndrome.
It is because high levels of tritium can cause acute and long term harm in this occupational setting, that tritium is continuously monitored, protective equipment is always required, and tritium uptake is regularly measured via urine sampling. As a result, no CANDU worker has ever received a tritium dose above the annual regulatory limit (5 rem / 50 mSv).
Stuart,
Thanks qualification. That must be a very confined space with a lot of evaporation. Can you point us to a reference which has the specifics/calculations?
Not a fan of annual limits. Daily limits would be far better. See
https://jackdevanney.substack.com/p/lnt-is-nonsense
In my day, it was commonplace to work in air-supplied plastic suits in the reactor vault with tritium levels of 400 MPCa, which *if unprotected* would be the equivalent of 1 rem/hr (10 mSv/hr). And that’s a huge space — thousands of cubic meters. When air driers are used they can cut the tritium level in half, but when the source is moderator water at 10 Ci/kg, it’s always going to be high MPCa.
This old document gives a description of the dose calculations p.45
https://canteach.candu.org/Content%20Library/19930207.pdf
Things can get interesting in Darlington’s Tritium Removal Facility as well
https://www.durham.ca/en/health-and-wellness/resources/Documents/EnvironmentandYourHealth/DNHC/Presentations/Sept2021/Tritium-Removal-Facility-OPG-EXCEPT.pdf
But ultimately, it’s only in these extreme, and well-controlled, occupational settings where there’s any substantial risk. I certainly agree with your overall point about the trivial hazard that tritium presents to the public. You’ve done great work pulling together this and also on LNT. 👍👍
Stuart,
Thanks docs. The canteach chapter is well written. Of course, it assumes LNT. Sigh.
This could be dangerous. The pre-1950 limit was 1 mSv per day. Basing the limit on the daily dose roughly matched our rad damage repair period. The current "tighter" worker limit is 20 or 50 mSv/y depending on where you are. It is possible to comply with the current limit and violate the old biology based limit by a factor of 20 or more.
But let me get this straight. You guys went into reactor building containment with the reactor operating? So much for the sensible Canadian stereotype. What were the gamma dose rates?
I’m talking about shutdown work — the tritium hazard remains high throughout a CANDU outage (but not everywhere…when I was at Pt. Lepreau for an inspection in the late 80s, early 90s, the tritium levels were so low that we were able to enter the reactor building without any respiratory protection. Not sure how they managed it.)
But, for most CANDUs, work can be done in the reactor building during operation, where there is adequate “biological shielding”, and nowhere near the reactor face, but it is very unusual and is always treated as high hazard work.
Regarding LNT, in practice the dose rates are also kept alara, and the occupational exposures are kept to no more than 2 rem/yr with other limits specified in the power workers union collective agreement, so I’m not worried so much about cell damage repair in this context. But it sure does drive up the operating cost.
Got it, thanks.
It seems like the obvious solution would be to thoroughly ventilate the reactor building on shutdown. Guessing regs and/or PR considerations prevented this (except possibly at Pt Lepreau?)
Yeah, no way we’d release to the environment, even when there’d be no actual impact. There’s your LNT again…an insignificant dose times millions of people implies calamity.
I like the be prepared to walk mentality. The NRC is still living in 1979 when the relative advantages of nuclear for air quality and low carbon were not really on the agenda
The US government should put out a tender for new nuclear regulations and see what kind of bids come in. The NRC needs to know the government is prepared to walk on them, they just won't create credible advanced nuclear regulations based on their mindsets and incentives
UCS is making a big deal of tritium from MSRs:
"Another troublesome radionuclide, tritium, with a halflife of 12.5 years, is highly mobile and cannot be effectively captured. Even with a costly off-gas control system, MSRs would almost inevitably discharge far more tritium and other radioisotopes into the environment during normal operation than solid-fueled reactors."
The counter-argument is:
"The solar salt loop captures any tritium that has made it to the secondary loop".
https://citizendium.org/wiki/ThorCon_nuclear_reactor/Debate_Guide#Radioactive_gases
How effective is this capture? Can we put some numbers on this?