Steve Jackson Games - Site Navigation
Home General Info Follow Us Search Illuminator Store Forums What's New Other Games Ogre GURPS Munchkin Our Games: Home

Go Back   Steve Jackson Games Forums > Roleplaying > GURPS

Reply
 
Thread Tools Display Modes
Old 11-13-2018, 10:36 AM   #41
Anthony
 
Join Date: Feb 2005
Location: Berkeley, CA
Default Re: DIY Nuclear Reactors After the End

It's also worth noting that nuclear power is extremely nonlinear. If you don't have a critical mass, you don't have a nuclear power plant. Critical mass for 15% enriched uranium is 600 kg (nuclear plants don't use spherical power cores and use neutron reflectors so actual critical mass is different, but there's no getting around needing a pretty large amount of enriched uranium to make even the smallest power plant).
__________________
My GURPS site and Blog.
Anthony is offline   Reply With Quote
Old 11-14-2018, 01:22 AM   #42
johndallman
 
Join Date: Oct 2010
Location: Cambridge, UK
Default Re: DIY Nuclear Reactors After the End

Quote:
Originally Posted by mlangsdorf View Post
The Reed Research Reactor (RRR) is a 250 kW pool type reactor Texas A&M's reactor is a 1 MW design with a staff of 30

A medium sized community could easily be built around one - a pair of 75W incandescent lightbults per household isn't much by 21st century standards but it would make for a very rich community post-AtE.
Sadly, pool reactors don't produce electricity. Those power figures are the amount of heat they can produce.

Converting the heat into electricity isn't very practical. A pool reactor is a large open-topped pool of water with the nuclear fuel, control mechanisms and so on submerged in it. That water is both the neutron moderator and the shielding. To generate electricity in any quantity, you need steam to drive a turbine or other steam engine to turn a generator. And if you run a pool reactor hot enough to generate steam, you boil the pool water, it stops moderating and the reactor stops generating heat.

Most reactors for electricity generation are pressurised water reactors, where the moderating water is confined under pressure so it doesn't boil. That lets you run it hot enough to generate decently hot steam.

Yes, you could use thermocouples to generate some electricity from a reactor that isn't hot enough to boil its water. They're about 1% efficient, as opposed to a turbine and generator, which are 20-30% efficient. So if you could capture all the heat of a 1MW (thermal) reactor in thermocouples, you could get something like 10kW of electricity.
johndallman is offline   Reply With Quote
Old 11-14-2018, 02:45 AM   #43
dcarson
 
Join Date: Mar 2008
Default Re: DIY Nuclear Reactors After the End

If they are north enough or high up in mountains just the thermal output could be useful.
dcarson is offline   Reply With Quote
Old 11-14-2018, 07:00 AM   #44
AlexanderHowl
 
Join Date: Feb 2016
Default Re: DIY Nuclear Reactors After the End

Geothermal would be more cost effective and safer for heat generation.
AlexanderHowl is offline   Reply With Quote
Old 11-14-2018, 06:04 PM   #45
mr beer
 
Join Date: Mar 2013
Default Re: DIY Nuclear Reactors After the End

"Just huddle up to the jerry-rigged nuclear reactor" has a very post apocalyptic feel though.
mr beer is offline   Reply With Quote
Old 11-15-2018, 07:42 AM   #46
AlexanderHowl
 
Join Date: Feb 2016
Default Re: DIY Nuclear Reactors After the End

One conflict for the setting though could be between the descendants of a back-to-nature grouo that survived the End with a society with a decent standard of living because of investments in geothermal energy and a new technology society seeking access to the nuclear waste depository that the group guards fanatically that was built before the End over the objections of their ancestors. The first society would believe that the depository is the prison of a demon that would destroy their existence if released while the second society thinks that they are superstitious idiots due to a misplaced confidence in their ability to handle nuclear power. Since their ancestors would have survived by allying with the military unit that protected the nuclear depository, the first society could have a surprisingly effective martial component and, with plenty of weapons, may be a challenge for the second society.
AlexanderHowl is offline   Reply With Quote
Old 11-15-2018, 08:22 AM   #47
Minuteman37
 
Minuteman37's Avatar
 
Join Date: Aug 2015
Location: Kenai, Alaska
Default Re: DIY Nuclear Reactors After the End

Quote:
Originally Posted by johndallman View Post
Sadly, pool reactors don't produce electricity. Those power figures are the amount of heat they can produce.

Converting the heat into electricity isn't very practical. A pool reactor is a large open-topped pool of water with the nuclear fuel, control mechanisms and so on submerged in it. That water is both the neutron moderator and the shielding. To generate electricity in any quantity, you need steam to drive a turbine or other steam engine to turn a generator. And if you run a pool reactor hot enough to generate steam, you boil the pool water, it stops moderating and the reactor stops generating heat.

Most reactors for electricity generation are pressurised water reactors, where the moderating water is confined under pressure so it doesn't boil. That lets you run it hot enough to generate decently hot steam.

Yes, you could use thermocouples to generate some electricity from a reactor that isn't hot enough to boil its water. They're about 1% efficient, as opposed to a turbine and generator, which are 20-30% efficient. So if you could capture all the heat of a 1MW (thermal) reactor in thermocouples, you could get something like 10kW of electricity.
Well if this is a nuclear winter apocalypse then it might not matter, BUT from the TRIGA (the kind of pool reactor being discussed) Wikipedia page

"The TRIGA Power System (TPS) is a proposed small power plant and heat source, based upon the TRIGA reactor and its unique uranium zirconium hydride fuel, with a power output of 64MWth/16MWe[5][6]."
Minuteman37 is offline   Reply With Quote
Old 11-15-2018, 08:56 AM   #48
Flyndaran
Untagged
 
Join Date: Oct 2004
Location: Forest Grove, Beaverton, Oregon
Default Re: DIY Nuclear Reactors After the End

Quote:
Originally Posted by mr beer View Post
"Just huddle up to the jerry-rigged nuclear reactor" has a very post apocalyptic feel though.
A nice way to reign in a Fallout setting for a more realism loving group.

It's also a good excuse for why a post apoc society maintained advanced scientific knowledge.
__________________
Beware, poor communication skills. No offense intended. If offended, it just means that I failed my writing skill check.
Flyndaran is offline   Reply With Quote
Old 11-15-2018, 01:55 PM   #49
johndallman
 
Join Date: Oct 2010
Location: Cambridge, UK
Default Re: DIY Nuclear Reactors After the End

Quote:
Originally Posted by Minuteman37 View Post
"The TRIGA Power System (TPS) is a proposed small power plant and heat source, based upon the TRIGA reactor and its unique uranium zirconium hydride fuel, with a power output of 64MWth/16MWe[5][6]."
Oh, sure. Much of the technology is the same. But you need a containment vessel, heat exchanger, turbine, generator, control systems, and so on. And rather more of the fuel. It's like saying that because a small car and an 18-wheeler truck both burn diesel, it would be easy to build a big truck out of a small car.
johndallman is offline   Reply With Quote
Old 11-15-2018, 03:26 PM   #50
jfleisher
 
jfleisher's Avatar
 
Join Date: Aug 2004
Location: Central Ohio
Default Re: DIY Nuclear Reactors After the End

What about finding a beached nuclear submarine and restarting the reactor?
__________________
"Think of it as Evolution in Action"... Larry Niven & Jerry Pournelle, Oath of Fealty

My Ogre Miniatures Blog: http://ogreminiatures.blogspot.com
jfleisher is online now   Reply With Quote
Reply

Tags
after the end, ate

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Fnords are Off
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 09:07 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2020, vBulletin Solutions, Inc.