# Nuclear power question. **URL:** \ **Category:** Factual Questions\ **Created:** [May 9, 2005, 9:25pm UTC](https://boards.straightdope.com/t/nuclear-power-question/303115 "2005-05-09T21:25:49Z")\ **Posts on this page:** 9\ **Page:** 2
**Author:** ![Waterman](https://avatars.discourse-cdn.com/v4/letter/w/b2d939/32.png) [@Waterman](https://boards.straightdope.com/u/Waterman)\ **Post date:** [May 11, 2005, 6:51pm UTC](https://boards.straightdope.com/t/nuclear-power-question/303115/21 "2005-05-11T18:51:28Z")
**Kevbo** thanks for the corrected info. What is the boron (or IIRC, the borates) for? Are they neutron adsorbers? ---
**Author:** ![minor7flat5](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/minor7flat5/32/258_2.png) [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)\ **Post date:** [May 11, 2005, 8:05pm UTC](https://boards.straightdope.com/t/nuclear-power-question/303115/22 "2005-05-11T20:05:02Z")
Yes. Boron is used to absorb neutrons. IIRC, they use that for both neutron shielding (e.g. borated poly) as well as for poisoning key areas in the reactor to provide a good reaction profile – so that the fuel is consumed evenly across the core. I don’t exactly remember if boron is commonly used for the poisons in the core or if they prefer something else. (Give me a break, it has been close to 20 years…) ---
**Author:** ![Waterman](https://avatars.discourse-cdn.com/v4/letter/w/b2d939/32.png) [@Waterman](https://boards.straightdope.com/u/Waterman)\ **Post date:** [May 11, 2005, 8:27pm UTC](https://boards.straightdope.com/t/nuclear-power-question/303115/23 "2005-05-11T20:27:57Z")
> [@minor7flat5](#): > > …(Give me a break, it has been close to 20 years…) Same for me as I last worked in the power industry 22 years ago! ---
**Author:** ![kidchameleon](https://avatars.discourse-cdn.com/v4/letter/k/898d66/32.png) [@kidchameleon](https://boards.straightdope.com/u/kidchameleon)\ **Post date:** [May 11, 2005, 8:44pm UTC](https://boards.straightdope.com/t/nuclear-power-question/303115/24 "2005-05-11T20:44:38Z")
Meanwhile, **Kidchameleon** is 50 feet from a cyclotron… ---
**Author:** ![Kevbo](https://avatars.discourse-cdn.com/v4/letter/k/e47774/32.png) [@Kevbo](https://boards.straightdope.com/u/Kevbo)\ **Post date:** [May 11, 2005, 10:11pm UTC](https://boards.straightdope.com/t/nuclear-power-question/303115/25 "2005-05-11T22:11:53Z")
The Boron water mix is the moderator, NOT an absorber. One of the safety features of a BWR is that when the mix converts to steam, it stops acting a moderator, With less moderator in the core, the reaction slows down, thus to some extent the BWR is self controlling, For a given control rod setting/fuel lifetime state it will tend to operate with a given percentage of the core water as steam. Note, IANANE (Nuke Engineer) I just got to work with some on a few electronic related (IAAEE) projects many years ago. Some of this I needed to learn, and some I learned from them because I’m a curious sort. I’m very sure the info I have posted is correct, but these postings represent nearly the full depth of my knowlege in the field of reactors. I could tell you a lot more about neutron coincidence counting and gama-ray spectrography though! ---
**Author:** ![Waterman](https://avatars.discourse-cdn.com/v4/letter/w/b2d939/32.png) [@Waterman](https://boards.straightdope.com/u/Waterman)\ **Post date:** [May 11, 2005, 11:08pm UTC](https://boards.straightdope.com/t/nuclear-power-question/303115/26 "2005-05-11T23:08:49Z")
As I posted before, it has been 20+ years since my direct involvement in the industry. At that time spent fuel rods were being stored at individual reactor sites along with depositories, such as Dresden IIRC. What is currently being done with spent fuel rods while waiting for the Yucca Mountain facility? ---
**Author:** ![minor7flat5](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/minor7flat5/32/258_2.png) [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)\ **Post date:** [May 11, 2005, 11:35pm UTC](https://boards.straightdope.com/t/nuclear-power-question/303115/27 "2005-05-11T23:35:22Z")
> [@Kevbo](#): > > The Boron water mix is the moderator, NOT an absorber. One of the safety features of a BWR is that when the mix converts to steam, it stops acting a moderator… It appears that boron is handy in many places :). Knowing nothing whatsoever about BWR, I can’t say much about that application. Nevertheless, in the PWRs I was involved with, part of the secondary shield was boron in polyethylene; the poly provides lots of hydrogen nucleii to slow down the neutrons, allowing them a better chance at getting absorbed by the boron. That BWR moderator steam bit is news to me – sounds slick, the BWR counterpart to the PWR’s self-regulation by water density (i.e. temp goes up =\> density goes down =\> more space between molecules =\> poorer moderation =\> neutron flux drops =\> power drops, and vice versa). ---
**Author:** ![Askance](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/askance/32/8281_2.png) [@Askance](https://boards.straightdope.com/u/Askance)\ **Post date:** [May 12, 2005, 4:51am UTC](https://boards.straightdope.com/t/nuclear-power-question/303115/28 "2005-05-12T04:51:40Z")
> [@+MDI](#): > > Nuclear waste is still radioactive, so why not just use the waste to generate more heat to make electricity out of? > > Is there a reason why this is not done? I’m not entirely knowledgeable about nuclear power, so this is probably a stupid question. Look at any oil refinery, you’ll see huge gas jets burning off “waste” gasses. Why not harness that heat? As with low-grade radioactive material, it’s just not cost-effective, or they’d be doing it. Even if it was, at some point the radioactivity from the waste would die down to the point it wasn’t economic, but it would still be active enough to be a hazard - then you still have the disposal problem. ---
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [May 12, 2005, 12:36pm UTC](https://boards.straightdope.com/t/nuclear-power-question/303115/29 "2005-05-12T12:36:28Z")
> [@commasense](#): > > A desire not to butt into other people’s business is eighty percent of all human wisdom. – Robert A. Heinlein Love that sig line. [Previous page](https://boards.straightdope.com/t/nuclear-power-question/303115.md?page=1)