accidents or incidents regarding nuclear powered naval vessels 2

[WillE]

given that a large part of the U.S. Navy is driven by nuclear "propulsion" and so little has been made through the years of any accidents or incidents concerning the heat source of this system of propulsion I am curious:
1> are any incidents or accidents regarding the heat source so classified as to never get to the news media or are they that safe.
2> are the incidents or accidents regarding the heat source so infrequent and so minor as to never deserve any scrutiny by the news media.
3> are the operators of this equipment so skilled and diligent that no incidents or accidents of any reporting magnigude ever reported.
4> is the equipment so skillfully engineered and constructed as to never have had an incident or accident requiring any scrutiny by the news media.

i am very interested and concerned about this information for some research I am conducting for myself. I have no nuclear training or substantive knowledge what ever and therefore am starting at square one in this project and need any assistance in regards to the first 4 questions that i can get.

 

[xnuke]

WillE,
I am an ex-Navy nuclear reactor operator/electronics technician/instructor. As far as I know, only minor problems have occured with Navy nuclear reactors. The design of the safety systems for reactor control, emergency heat removal, and radioactivity containment is paramount. The government can afford to spend a lot of money on the engineering of these systems, as they have no worries about turning profits like utilities do.

The training program I went through/taught in is by far the most arduous schooling I have ever been through (and yes, I have a BS in Physics/Math - nuclear power training was way harder than college). The students blow away any I ever taught in the civilian world as far as ability. Any minor fraction that casts doubt on a student's reliability or integrity results in their immediate dismissal from the nuclear power program. Any failure to meet the demanding and rigid academic schedule results in dismissal. Admiral Rickover insisted on quality in engineering and training within the program. That quality is still maintained today.

Links:

http://www.fas.org/nuke/guide/usa/facility/knolls_s.htm

http://www.lmsg.lmco.com/kapl/

http://www.fas.org/nuke/guide/usa/facility/bettis.htm

http://www.bettis.gov/

In regards to your questions, my answers are (to the best of my ability):
1. They're that safe. I know of no large accidents in the fifty year history.
2. Incidents deserve scrutiny if large enough (there haven't been any that I know of), but I believe the containment systems can protect the public.
3. Yes. We practiced casualty drills very frequently to ensure we could safely operate.
4. Yes. The reactor itself is of an intrinsically safe design - unlike Chernobyl.
Please remember, these are my opinions that reflect my experience within the Navy nuclear power program. [sig][/sig]

 

[WillE]

in regard to your response "The government can afford to spend a lot of money on the engineering of these systems, as they have no worries about turning profits like utilities do." I look at the facility that a commercial power company has to construct, complete with upstream emergency water (i.e. Commanche Peak in Glen Rose, Texas). I am primarily curious about the safety record regarding these mobil reactors in contrast to the safety record of the stationary reactors contained within these large plants. The operating environment of the mobil reactors is extraordinary, at least to me, being pitched about from time to time (particularly on the aircraft carriers) and still being in possession of the safety record that they are.
By my own census the Navy has more than 100 of these mobil reactors in service today. And there are many submarines that were operated by these mobil reactors that have been de-commissioned. I am just starting this research and it is inconceivable to me that some system similar to that of one of the types used by the Navy could not be commissioned for operation in the civilian world. The production of the electricity itself is rudimentary and very similar to what was employed in 1860 (turn a magnet inside of a coil) only the heat source has become more exotic. (of course i realize that the technology is vastly improved the elements are similar). I was musing (mentally) about the power (electrical) requirement for an aircraft carrier and then further about the requirements to service the turbines that are used to propell the thing. Just the electrical componet could service a large town or small city and if the propulsion component were also used to produce electricity, well, I need more data, not more imagination.
Thank you for your timely reply and very helpful answers. [sig][/sig]

 

[xnuke]

"...it is inconceivable to me that some system similar to that of one of the types used by the Navy could not be commissioned for operation in the civilian world." An interesting statement. A few reasons why this will probably never happen in the U.S.:

1. Fuel costs - Naval reactors used highly enriched uranium for fuel; commercial reactors use uranium enriched to a few percent U-235. This drives the fuel costs up enormously.
2. Public opinion - The prevailing negative attitude toward anything nuclear in the U.S. today is a huge factor. I believe this has occured to a lack of education about the dangers of radioactivity and nuclear power.
3. Waste - No adequate answer has been found to the question of waste disposal. For more info on this see

http://www.radwaste.org.

It has some good stuff. I think nuclear power is a good idea - but the waste problem has to be overcome.
There are many other reasons...these are just major ones. I believe nuclear power can succeed if run by the government. Look at France, for example. I think they produce over 50% of their power from nuclear plants (it may be closer to 70%, I'm not sure), and it has had a tremendous impact on issues like air pollution and reliance on fossil fuels.

Back to the safety question:
The reactor plants used in Navy ships are remarkably simple compared to what you might think, as simple systems have less ways to fail than complex systems. Only proven technology is used to ensure reliability. Design changes are thoroughly tested on prototype reactors before being tested on a few ships in the fleet, then introduced fleetwide. The process of change seems to take forever. The systems that are affected by pitch and roll are designed to compensate for it (I can't tell you how, I'm not allowed). The operators can be more affected by it than the plant - they can get seasick!

Best of luck with your research. I wish I could give you more concrete info about Navy nuclear power, i.e. data, but I'm not allowed.
[sig][/sig]

 

[WillE]

Thank you again for your valuable insight … I don’t want to seem to be gushing here but you have helped a lot. Actually your help has been in confirming some of the answers I had intuitively assigned to some of the questions.
I was of the opinion that commercial reactors were non-economical, poorly engineered, overly complex, sloppily operated aberrations. You may have pushed my attitudes over the edge. How could public opinion favor what is going on in the commercial sector? I have never heard anyone, at all, in any media position or any person connected with the U.S. Navy expound on the remarkable safety record of nuclear power within the Navy. I have never heard any one anywhere in any position of expertise recommend or in any way suggest that commercial nuclear power concerns might just take a page or two from the Navy’s history of nuclear power and apply its successes to the commercial sector. I have enough study in physics to understand the inherent dangers of radio active material. There is this matter of the ‘real world’ vs theory and the best two examples I can think of are Hiroshima and Nagasaki. Two of the dirtiest reactions in history took place there. And people not knowing that they were supposed to get sick and die, moved back there, grew vegetables and ate them and had a plethora of children, with out dramatic bad effect (there are of course some bad effects but none as great as our Love Canal. (chemical not nuclear). The places where the DOE and DD tested its nuclear warheads is I suppose liable to be off limits for the next 250,000 years or so. And therefore people hear only that. No one associates the lives of the people of Hiroshima and Nagasaki after the war. The only pictures prevailing on the media or in the text books are the ones shortly after the detonations. Given that an aircraft carrier sets out from the shipyard upon completion and sign off with 22 years of fuel on board, I really wonder what the real cost of that amount of fuel oil or coal would be, in total, considering handling, storage and market flux. I wonder just how much the additional cost of the nuclear fuel really is factoring in those considerations. Additionally considering that the nuclear fuel purchased today will only increase in value in the next 22 years too. It is already acquired, stored and available. The fossil fuels for the standard electrical generation plant are not. How much is the real cost of damming a river, creating a lake and doing the hydro-electric thing. The opportunity for undisclosed costs in loss of land usage are totally incalculable.
Waste disposal is the real dilemma! And as with the current thinking concerning commercial nuclear powered electrical generation not much is being dedicated in resources to solve the problem. We can spend actual billions of dollars shooting little toy cars to Mars. We are doing very little about nuclear waste disposal or recycling (if that were possible).
I think your observation about successful nuclear power generation could be effective if run by the government is highly astute. Think about how effective it would be if run by the Navy. (I am not being sarcastic.) The Navy has done remarkably. It is a simple matter of appropriations. Money is driving this whole issue and 7% of our domestic energy consumption is being filled by Iraqi oil. I hope that makes you as uncomfortable as it makes me. And I am sure France is not running on the U.S. Naval model.
Clearly the on-board ship reactors are somehow gimbaled. And you did not say it and need not confirm nor deny it.
I am not surprised that the equipment is engineered to be simple. Engineering simplicity is much more difficult than complexity and is why is not more frequently done. ( I can do a whole paper on just that topic!)
I do not know if you know or ever have heard of Capt. Richard D. Raaz. He and I were boyhood friends and both raised within the confines of the U.S. Air Force. His father was a lawyer and mine in aircraft operations. I have never broached any of these topics with him and never will for the same reasons you indicate. We all have things that just have to remain as they were.
Thank you again, I think I can go on without troubling you for any more of your time.

Wm. Erwin L. II
[sig][/sig]

 

[Dan76]

WillE, I just saw your thread and wanted to add a little bit to xnuke's comments, I'm another ex-navy nuke (an Electrician NOT to be confused with an Electronics Tech :b)
so here are a few points I thought may be enlightening.
1) The Navy Reactors xnuke and I worked on were on Warships so many of the design criteria may be overkill for a civilian plant, ours were designed to be depth charged, shot at, and generally mistreated in combat, and as xnuke said they are very simple and rugged. Also they are relatively compact and inefficcent (from a thermal perspective, for power v/s size they're great!) A utility wants to draw every last BTU (or Joule if you prefer) of energy out of the fuel they buy, so a complex plant is often built to accomplish this. A Warship plant is also designed for very rapid power changes, where a civilian plant runs at a constant near 100% Power all of the time meaning they more safely approach their perfomance limits, since power changes are slow and small.
2) The Navy Limits for Radiation are usually one-tenth of the Required civilian limits (Which are still quite Low)
3)Per your post "We are doing very little about nuclear waste disposal or recycling (if that were possible)." Disposal is Mediocre but YES we CAN RECYCLE but we DON'T!
sorry Spent civilian fuel has plenty of U-238 and various mixed-oxides of plutonium (Very Poor Bomb Material) there are many designs of reactor (CANDU in Canada being one) that can "burn" this type of Fuel, unfortunately the US is way behind in using this resource.
4)Per Your other post "Think about how effective it would be if run by the Navy. (I am not being sarcastic.) The Navy has done remarkably." I will say that the Nuclear Regulatory Commission (check it out at

http://www.nrc.gov)

Has done a good job and Admiral Rickover deliberately set the Navy apart from the civilian power industry since as stated above utilities are a buisness the Navy is not, yes the reactors would be safe, tough, and well run but would not economical at all, While the military is not deliberately wasteful, readiness not profit is the first priority. However in a way the Navy does contribute to the civilian Industry, many Navy Nukes get jobs at civilian reactors when they leave naval service, Where else do you find a 24 year-old guy with four years of experience and the equivalent of an associates degree in Engineering?
5) As to France and their nuclear industry, actually they are closer to the naval model than the US. They all use the same Reactor plant type (2-Loop Westinghouse), If one Plant has a problem they tell the other plants to look out for a similar problem, and the coolest thing is they actually take regular people on tours of the plant so they can see what is inside, since ignorance breeds fear.

Hopefully this was helpful if you want to learn more try typing "Nuclear Engineering" into a search engine, I've found many interesting and informative websites, and you don't have to be a nuke to understand them. If you're looking for some good reading, which may be slightly anti-nuclear, try to find "We Almost Lost Detroit" I can't remember the authors name and lost my copy. It was a popular book on my ship, and it's pretty accurate (Unlike some of the crazy anti-nuke propaganda/trash some people write)


-Dan76

P.S. Thanks for not believing some of the trash on TV and the Movies, unfortunately that's all most people see.

 

[ChasBean1]

I'm also an ex-navy nuke, and what xnuke & Dan76 said are accurate and well said. I was in from '86 to '92 and never knew of any reactor incidents. And no, we're not programmed to say that! The navy control room is much less complex; the plant has people at strategic locations throughout, in addition to the control room. Casualty control procedures are drilled relentlessly.

One item to note is that is that a navy plant might typically average 15-35% plant power and frequent shutdowns, whereas a civvy plant would typically run flat-out. Operating at a higher powers decreases allotted reaction time to abnormal conditions, such as loss of feed to the steam generators, and exponentially compounds decay heat removal concerns after shutdown.

 

[TheBlacksmith]

As another x-nuke, currently working in a nuclear shipyard, I can confirm all these thoughts. The Navy plants (and the French plants too), use a limited number of designs, so lessons can be shared, layouts are familiar, etc. At one point, every power plant/boilermaker in the US built commercial nukes. Can you imagine flying if every airplane was different, instead of the handful of different cockpits we have. Also as broached in other forums here, there was a problem with the geometric sizing approach - just make everything in a functioning 10 gigawatt plant 5 times as big and you should get a perfect 50 gigawatt plant. By and large the Navy was very conservative in its plant design and also built a land-based prototype of every plant to proof the design, provide hands on training and run simulations throughout the life of the core. Also, the fact that the Navy plants are mobile and may get shot at lend another layer of conservatism. As for specifics, the power ratings, etc are restricted data, so you'll not get specifics unless someone wants to be prosecuted. Nuclear power makes sense for carriers, as the amount of fossil fuel required, its storage space and the logistics of getting fuel oil to the carrier would make the design impractical. Fossil-fueled carriers spend several hours alongside "oilers", every 2-3 days taking on fuel. As a young Naval Officer, I observed that all you had to do was sink the poorly armed oilers and wait for us to 'run out of gas." For smaller ships, i.e. cruisers, it makes less sense. And of course, not needing air for combustion means that only nuclear subs are true submarines, all others are surface ships that can submerge for limited periods.

Blacksmith

 

[TheBlacksmith]

As another x-nuke, currently working in a nuclear shipyard, I can confirm all these thoughts. The Navy plants (and the French plants too), use a limited number of designs, so lessons can be shared, layouts are familiar, etc. At one point, every power plant/boilermaker in the US built commercial nukes. Can you imagine flying if every airplane was different, instead of the handful of different cockpits we have. Also as broached in other forums here, there was a problem with the geometric sizing approach - just make everything in a functioning 10 gigawatt plant 5 times as big and you should get a perfect 50 gigawatt plant. By and large the Navy was very conservative in its plant design and also built a land-based prototype of every plant to proof the design, provide hands on training and run simulations throughout the life of the core. Also, the fact that the Navy plants are mobile and may get shot at lend another layer of conservatism. As for specifics, the power ratings, etc are restricted data, so you'll not get specifics unless someone wants to be prosecuted. Nuclear power makes sense for carriers, as the amount of fossil fuel required, its storage space and the logistics of getting fuel oil to the carrier would make the design impractical. Fossil-fueled carriers spend several hours alongside "oilers", every 2-3 days taking on fuel. As a young Naval Officer, I observed that all you had to do was sink the poorly armed oilers and wait for us to 'run out of gas." For smaller ships, i.e. cruisers, it makes less sense. And of course, not needing air for combustion means that only nuclear subs are true submarines, all others are surface ships that can submerge for limited periods.

Blacksmith

 

[tstead]

Naval Rxs are normally operated at about 1/3 full power? Just out of curiosity, what is done to prevent severe axial flux tilts???? How often (and expensive) do you change control rods or do you just borate the heck out of the coolant?

Regards,
Tim S.

 

[tstead]

Seems to me I rememebr in college hearing about an accident with a Navy nuke sub where the Rx was shut down for some reason. When they tried to restart the Rx to get power going, they couldn't becuase of Sm and Xe buildup.

The sub sank and everyone aboard died.

What sub was this and when did this occur? Why was the Rx shut down and did the officers not know about fission product poisioning?

Regards,
Tim S.

 

[TheBlacksmith]

You are probably referring to the USS Thresher. For a good explanation go to this link

http://www.tcnj.edu/~rgraham/failure1.html#01

Blacksmith

 

[WillE]

Thank everyone for the postings, they have been very informative. The reason I posed the questions in the first postings had everything to do with California’s self imposed energy “crisis”. Of course they have not built a new power plant in the last 20 or so years while their population has been increasing exponentially at the same time, both from within and from immigration. As a nation we are importing amazing quantities of oil and much of those imports are used for the production of electricity along with coal, much of it imported from Canada. This to me seems to be bad policy in all regards, particularly in the regard of National security and defense.
What is obvious to me is that the current policy concerning the design of commercial (civilian ) nuclear power plants is badly flawed. It is my opinion, bolstered by the input of this group, that simpler, cheaper and easier to use nuclear plants could be produced somewhat based on the Naval model. I am not advocating that the same units be produced for civilian use but that the current designs be scrapped and new, safe designs be implemented somewhat on the Naval model. Of course the design criteria would be different, stationary as opposed to being on a moving vessel, constant power requirements as opposed to scalar requirements and so forth but simplicity of design and elimination of much of the concrete and length of time and expense in construction is accomplishable and therefore should be undertaken.
Of course the discussion would be turned to the perceived problem of waste disposal. And it was noted by Dan76 that as a country, we are not recycling our nuclear by product as Canada is, for example. Of course the other thing is that we don’t seem to mind spending our progeny’s money for the promotion of the “space boy scouts” and their wonderful scientific endeavors that have included “studying” growth patterns of pine trees in near earth orbit (there is a monument to scientific endeavor, if one could ever imagine what commercial value we would ever derive from producing pine trees in space, or of course there is the study of frogs in a weightless environment, all I saw was freaked out terrified frogs in something closely resembling animal abuse). I don’t know if it would be within the domain of NASA to study the recycling and disposal of nuclear waste but it is someone’s purview and those people should be getting the resources to do just that. California, by the way is way short of water, imagine the consequences of using surplus power and/or residual heat to accomplish large scale de-salinization of sea water, I think that California has an abundance of the raw material at hand. They have not accommodated the water requirements for their increased population either.
I think that one of the factors in the design of Naval nuclear reactors might be the abundance of cooling water, obvious in a marine vessel. Our country has abundant water on all sides. The oceans on the East and West coasts, the Gulf coast and the Great lakes. The Commanche Peak nuclear power plant was built close to where I live. I live in what is a dry nearly desert biome. Nuclear power plants are not advisable in such areas. Of course there is a large lake nearby to handle any contingency, and I wonder just how much it would really help if it were truly needed. All of the afore mentioned sources of water would and could accommodate large problems and they are also near the need, the mass of the population, where not by any coincidence, the electricity is also needed.
Thank you all for sharing the benefits of your experience, it has been most helpful to me in one regard and causes me even more frustration in another.

Regards,
William E.

 

[ChasBean1]

tstead, if I remember correctly, the fuel is loaded in a manner that prevents flux tilting by loading higher fuel concentrations in some areas and adding poisons to other areas such as the core perimeter, which also helps prevent buckling (flashback to my nuke school in '87). Also the control rods are only replaced during refueling and water is not borated unless there is an emergency. The 1/3 power on average that I mention is just proportional to average ship speed: near-shore and maneuvering ops would be very low power, crossing the ocean at high speed would be high power. In my experience, most of our time was not spent with engines at ahead-flank.

Hope that answers your question okay...-Charlie

 

[tstead]

So naval Rx's rely more on burnable poisons than control rods to inhibit high power operation? What I was imagining was the core operating over its cycle with the rods partially inserted all the time which would be just shear hell on the flux profile and burnup - not to mention the cost of replacing control rods more often.

I would also assume that the low power ops is to allow for fast start-ups after a SCRAM without having to wait for the Xe and Sm to decay away. Is this correct?

Is borated water not used becuase of the very high enriched fuel that is used and problems that could occur at start-up of a clean, fresh core?

I'm just curious about the differences between naval and commericial Rx's since all my knowledge (and education) is based on commericial Rx's.

Tim S.

 

[elguapo]

tstead: um, i can't imagine anyone'll get that detailed as we're sort of getting into the "i could tell you but i'd have to shoot you" area. i could be wrong though (ex-elt instructor here btw)

 

[Dan76]

tstead, elguapo is correct, there are some things we can't discuss. Core design, and specific #'s, being a few.
If you want to find out more check out these websites:

http://www.iss.external.lmco.com/kapl/

http://www.bettis.gov/

I dont believe they contain very detailed technical info but perhaps you can talk to someone who can tell you more.
You could if you are very curious apply for a job, 6 months of Nuke School in Charleston, SC + some hands on in Charleston or Ballston Spa, NY and you will learn all you care to about Naval Reactors. Please dont take this as a blow off, all of us signed a paper at one time or another, so generalities are all you can expect.
Regards, Dan76

 

[tstead]

Alright....

I never was in the Navy - although I had seriously considered going into the NUPOC program right out of college. I received my B.S. in Nuclear Engineering from the Univ. of Mo - Rolla so none of my knowledge is "classified" - if you know what I mean.

I'll check out those web sites...

Tim

 

[ChasBean1]

Sorry, I haven't checked this in a while. I can't confirm or deny the fact that.... blah blah blah. No actually they rely more on rods, but rods aren't fully extracted. Controlling rod height will change throughout the life of the core as fuel gets burned. Rods control the reactivity & handle the transients, but the fuel and burnable poison loading within the fuel cladding (not in the coolant) helps to promote even burning while the rods are doing their thing.

The low power ops aren't for a "purpose" other than that low power results from the engines not always going full speed. I forgot all about xenon transients until you just mentioned them, so I'm not sure about that.

I hope that's not too classified, as I remember the classification relating more to operational parameters of plants of specific ships. What I'm saying is general and I'm not giving allowable heatup rates, cooldown rates, operating temperatures & pressures, etc. - these are the things I remember having to hush about. Hope that helps, -Chas

 

[tstead]

What is the period of a naval reactor after a SCRAM?

*grin*

You can't tell me that information is classified since its the same for any U-fueld reactor: -80 seconds or so (actually, I think it's closer to -81.5 seconds). Just playin