reactor core life of Astute.

[david h]

Hello,

Hopefully i'll get more of a response than last time..

I read that the core of the new HMS Astute class boat is designed to last the life of the vessel. The Uranium core is called an "H" core I believe and although they say it will run for about 25-30 years they don't say how this is achieved. ( now i realise that I might probably get a response saying, "thats' classified" yeah well, you could still give me an educated guess. Maybe from someone more educated in this matter than me.

previously nukes needed to be refuelled every 10-15 years. This is incredibly expensive to do and so making a boat that does not need to be refuelled is a real bonus. How come this was not possible with previous generations?

I'm guessing that either,

the core is really big?
The core has a far greater concentration of U-235 over U -238 I realise that this would require major leaps in separation technologies, (I've heard of Aerodynamic and Laser separation techniques have becoming a reality.)?
The reactor design and turbine system is far more efficient. systems use less power?

could someone please enlighten?

David H

[JWLaRue]

Re: reactor core life of Astute.

I'm not a nuclear engineer, but a quick internet search yielded the following from wikipedia:

"Long core life is enabled by high uranium enrichment and by incorporating a "burnable neutron poison" which is progressively depleted as non-burnable poisons like fission products and actinides accumulate. The loss of burnable poison counterbalances the creation of non-burnable poisons and result in stable long term fuel efficiency."

-Jeff

[david h]

Re: reactor core life of Astute.

thanks jeff,

Sounds like it may also avoid build up of Xenon -135.


thanks,

Dave

[Rogue Sub]

Re: reactor core life of Astute.

Well now a question I think I am finally qualified to answer.

Comparatively
The size and out put of the reactor has gone up
I have seen s1w, s3w, s5w, s6g, s8g, s9g reactors and there is usually a nice step in size. Some of the later reactors dont have as large of an increase inside but have much more efficient designs. Distribution of preloaded fuel poisons, control rod configurations, shape, and coolant flow all play a part in what you will get out of your hot rocks. Also, as stated before a larger enrichment plays a part in this . Throw this in with years of plant building and we get higher efficiency plants to boot. Now my knowledge is restrained to US boats but I do believe the brits get their toys form us just like their nukes.

You should see a reactor from the carriers.....so big (for a sea going ship)

Does this make sense? Most of the basic info can easily be found on the net these days. In fact there is a college book out there that is very informative if you have a higher curiosity.

Kevin

[Guest]

Re: reactor core life of Astute.

We've designed and built our own reactors since the Valiant class (Rolls Royce). The only British sub that used a U.S designed reactor core was Dreadnought, which used the entire stern of a Skipjack class with our own section from amidships on.

This boat was retired early from service, I believe as a result of stress cracking between the two hull segements.

[Rogue Sub]

Re: reactor core life of Astute.

What do you use for your designations now? I only knew about the use of the s5w.

[Guest]

Re: reactor core life of Astute.

Have a look here-

http://en.wikipedia.org/wiki/Rolls-Royce_PWR