3 ms·

1MW worth of power from fusion would generate enough radiation to kill a stadium full of people in a fraction of a second without a lot of shielding, Well, it

1MW worth of power from fusion would generate enough radiation to kill a stadium full of people in a fraction of a second without a lot of shielding, Well, it depends on the reaction. The p-B reaction ( http://en.wikipedia.org/wiki/Aneutronic_fusion#Residual_radiation_from_a_p.E2.80.9311B_reactor http://en.wikipedia.org/wiki/Aneutronic_fusion#Residual_radi... ) releases the vast majority of its energy in charged particles, which could potentially be converted directly to electricity with not much physical shielding. (Not that that has anything to do with the linked article, of course).

Retric 15y ago
Sure, the energy of these neutrons would account for less than 0.2% of the total energy released, but do some math. http://en.wikipedia.org/wiki/Sievert http://en.wikipedia.org/wiki/Sievert The unit gray measures the absorbed dose of radiation (D), absorbed by any material. The unit sievert measures the equivalent dose of radiation (H), having the same damaging effect as an equal dose of gamma rays. Both the gray, with symbol Gy and the sievert, with symbol Sv are SI derived units, defined as a unit of energy (joule) per unit of mass (kilogram): 1 Gy = 1 Sv = 1 J / kg So, 2KW of gamma rays = 2000 joule per second = 2000 Gy / second. But high energy neutrons are significantly worse than gamarays so you need to multiply that by a (function of linear energy transfer L in keV/μm) but in this case we are dealing with a few different reactions all of which are producing 2+ MeV neutrons so it's 2000 times worse than Gamarays. But, how bad could 4,000,000+Gy / second be? http://en.wikipedia.org/wiki/Radiation_poisoning#Table_of_exposure_levels_and_symptoms http://en.wikipedia.org/wiki/Radiation_poisoning#Table_of_ex... 6–8Gy = 95-100% Mortality Granted that's 360^2 degrees so it's spread over 4Pi*R^2, but newton radiation also is really nasty and hard to shield.
- Retric 15y ago
  Ops, linear energy transfer is way more complex than I thought: http://en.wikipedia.org/wiki/Stopping_power_%28particle_radiation%29 http://en.wikipedia.org/wiki/Stopping_power_%28particle_radi... it turns out that really high energy particles are less dangerous relative to their energy. Still going to kill everyone in a mid sized building vary quickly without a lot of shielding though.

Retric 15y ago

Sure, the energy of these neutrons would account for less than 0.2% of the total energy released, but do some math. http://en.wikipedia.org/wiki/Sievert http://en.wikipedia.org/wiki/Sievert The unit gray measures the absorbed dose of radiation (D), absorbed by any material. The unit sievert measures the equivalent dose of radiation (H), having the same damaging effect as an equal dose of gamma rays. Both the gray, with symbol Gy and the sievert, with symbol Sv are SI derived units, defined as a unit of energy (joule) per unit of mass (kilogram): 1 Gy = 1 Sv = 1 J / kg So, 2KW of gamma rays = 2000 joule per second = 2000 Gy / second. But high energy neutrons are significantly worse than gamarays so you need to multiply that by a (function of linear energy transfer L in keV/μm) but in this case we are dealing with a few different reactions all of which are producing 2+ MeV neutrons so it's 2000 times worse than Gamarays. But, how bad could 4,000,000+Gy / second be? http://en.wikipedia.org/wiki/Radiation_poisoning#Table_of_exposure_levels_and_symptoms http://en.wikipedia.org/wiki/Radiation_poisoning#Table_of_ex... 6–8Gy = 95-100% Mortality Granted that's 360^2 degrees so it's spread over 4Pi*R^2, but newton radiation also is really nasty and hard to shield.

Retric 15y ago
Ops, linear energy transfer is way more complex than I thought: http://en.wikipedia.org/wiki/Stopping_power_%28particle_radiation%29 http://en.wikipedia.org/wiki/Stopping_power_%28particle_radi... it turns out that really high energy particles are less dangerous relative to their energy. Still going to kill everyone in a mid sized building vary quickly without a lot of shielding though.