Shielding Wall design complete, bidding begins
(6) CommentsWith the help of Dr. Mohamed Sawan of the University of Wisconsin, Madison, Dr. Subramanian and Mr. Lerner have completed the design of the shielding walls.
Design specs
The shielding walls will be 2.5 feet thick, and made of concrete enriched with 2.9% boron, the composition used in other fusion facilities.
Using the MCNP simulation program, we calculate that the shielding will reduce the biological dose of the neutron by a factor of very close to 3,000, and will essentially eliminate the gamma-ray and x-ray radiation.
This means that for the worst case of 10^13 neutrons per pulse and six pulses per hour, no one can be exposed to more than 1 mrem per hour, under the OSHA requirement of 2 mrem/hr.
For an annual average of 2,500 pulses, an optimistic figure, annual exposure will be under the background level of 500 mrem; even with the unrealistic assumption that all pulses produce the worst-case radiation.
Bidding begins
We are now getting bids from contractors to build the wall, lay a new concrete floor, upgrade the heating of the facility and install air-conditioning.
We still have to design and test the shielding for the narrow beams of neutrons that must be allowed out to the time-of –flight detectors, which will use the spread in velocity of the neutrons to determine their energy and thus the temperature of the ions that produce them.
Capacitors, Switch, Vacuum Chamber, Drift Tube
Simulation progress
Comments
For a more in depth discussion, start a thread in the forums.Am I correct in assuming that this level of neutron production is a development stage issue only, and that nothing like that kind of shielding would be required in a production generator?
Of course they will require shielding, but it will be less because of BH fuel and because the shielding will be more efficiently placed.
Breakable;
All that is implied as given in my question; I guess I was asking about the degree of difference in some kind of quantitative terms.
The patent calls for 1 meter of water, plus 2 cm of boron. This type of shield is a lot easier in the production world than it is in a lab setting.
How to raise your karma and lower your neutronicity:
I wonder how “neutron-poor” a production model can become, in the ideal case when isotopically pure p-B11 fuel is being used and neutron-producing plasma contaminants (beryllium?) are avoided.
An FF reactor that requires only minimal shielding (X-ray or soft-gamma) could have great prespectives in aviation and spaceflight.
The prospects for naval and rail are far greater, IMO, for some time to come. But of course long-duration spaceflight would be a natural application, too.
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