Saw some posts below from some of those F'n NUKES talking about NTS CHAS. Anyone else train on the great flushable Rx?

If you did, come on, SPILL the beans.....

We all know that hafnium can be dispensed with....

Nope...managed to avoid that "plant"....

I have no clue what you are talking about. I trained on A1W. That was hard for me since I learned about a S5W plant in Nuke school, then go to somthing totally different.

Good old "alice in wonderland"....

I got S5W in nuke school, then S8G prototype...
a slight change, to say the least.

MARF


The S7G was a design of United States Naval reactor that did not use control rods. It was tested in the early 1980s at the Modifications and Additions Reactor Facility (MARF). It consisted of a unique reactor core installed in a modified S5W reactor plant.

Instead of moveable hafnium-based control rods, which are used in all other United States Navy reactors, reactivity in the S7G core was controlled by stationary hafnium-clad tubes partially filled with water. Water could be pumped from the portion of the tube inside the core up to a reservoir above the core, or allowed to flow back into the tube. A higher water level in the tube within the core slowed more neutrons, allowing them to be captured by the hafnium, thus lowering the power level. The pumping system was configured so that the pump needed to run continually to keep the level pumped down; on loss of power, all the water would flow back into the tube, shutting down the reactor. The design had the advantage of negative feedback: an increase in reactor power caused the water to expand, thermalizing more neutrons, lowering the power.

The "S7G" designation indicates that it was designed for use in submarines and was the 7th such design by General Electric.

The S7G was never used on a ship, and the prototype was fitted with rods in the late 1980s.

***I believe the above originated with Naval reactors**

I remember reading somewhere that it was a way for Adm Rickover to prove to hafnium companies he didn't "need them" to force them to drive their prices down. Not sure how true that was.

But I was trained and taught at MARF (post Rods-I wasn't born yet when it was water controlled). a weird platform to say the least even with rods.

"Merely Awaiting Reactor Fill"....

It added some interesting limitations to the S8G prototype, as well.

ok - that is weird. I wonder how reactor control would be if that was in a sub on the surface (would the water slosh around?)

quote:

Originally posted by dbil:
ok - that is weird. I wonder how reactor control would be if that was in a sub on the surface (would the water slosh around?)

No one ever said it had to be practical, just that it work.

PO1-I would argue it was more the reactor fill system on thw whole that added limits. If S8G was doing stuff on their half, MARF was limited and vice versa. crazy requirements.

You have to understand that projects like MARF were back in the days when silly concepts could get humongous funding as long as it was linked to fightin' them dirty Comminist bastages. MARF was halfnium free because someone was worried that the worlds Halfnium supply would be controled by Comminist Bastages and they wouldn't share. Bada bing, bada bam. There you go.

I did prototype at S5G, then went to an S8G T-hull. That was kinda cool seeing the technology matured.

Cat, you're right about the fill system imposing the limits. But, since I was an S8G student, and the material was explained to me by an S8G instructor, and we at S8G didn't really like MARF...

Besides, it's funnier that way.

quote:

Originally posted by dbil:
ok - that is weird. I wonder how reactor control would be if that was in a sub on the surface (would the water slosh around?)

The control tubes had baffles designed to enable their operation while going through seas.... but I don't know if I would want to try it.

The design itself was ingenious..... Theoretically, once the tubes were in spill, it could operate until core EOL without any operator intervention, since the tubes automatically corrected for temperature and power changes...

quote:

I did prototype at S5G, then went to an S8G T-hull. That was kinda cool seeing the technology matured.

ok, S5G was shutdown when i went to prototype. Alice in Wonderland is a good description of A1W. It had 2 reactors (supposed to be 1/4 of the Enterprise). We trained on 1 reactor and othe other one was for "testing". It ran at 100% nonstop via a steamdump. (extremely loud since the condenser ran at atmosphereic pressure). Then one day the Navy realized it didnt have a replacment core - opps!

Aslo one reactor primary system was made out of regular carbon steel to see how it corroded. Needsless to say it had alot of hotspots. one time i was to help with SGWLC testing. The hookups were INSIDE the RC and rusted shut.

That place was alot of fun (sarcasm)

I sort of enjoy the real plant I get to play around with...the rods are all the way out, and we dilute the boron....no pesky shims (at least not normally. We have been known to move the rods for testing)...

The best part? I get to go home every night. Oh, yeah...and no hourly logs....and internet....and fresh air....and sunlight....and very very few drills....and this place is HUGE!....and I get to drink beer and other adult type beverages while not on watch....

That's a lot of best parts, isn't it? Sorry.

quote:

Originally posted by catherine0830:
I remember reading somewhere that it was a way for Adm Rickover to prove to hafnium companies he didn't "need them" to force them to drive their prices down. Not sure how true that was.

But I was trained and taught at MARF (post Rods-I wasn't born yet when it was water controlled). a weird platform to say the least even with rods.

Oh damn...... now I feel O L D! !

Gee.... Thanks!!!

Ah well....... You young whippersnappers jus' don' know.....

quote:

Originally posted by Silent_Surface:
Oh damn...... now I feel O L D! !

Gee.... Thanks!!!

Ah well....... You young whippersnappers jus' don' know.....

!!!!! Glad I could help!

When I was up in NY they were dismantling the remnants of D1G and S5G.

What about Castle Greyskull and S1C??? Good times there....

Wow, talk about some memories.

I wasn't assigned to MARF, I was at S3G.

But I remember our class being given a lecture not to talk to reporters about what went on at the base. Apparently some guy was being a smart a** and told some reporter that MARF stood for Missle Assembly and Refueling Facility....and that got into print and brought out a WHOLE bunch of protesters!

Yeah, we heard the folks up in New York weren't the sharpest tools in the shed, that boomers would sneak up the "underground river" for rearming their missiles. At least they didn't have that problem at S5G. However, life did have it's "interesting" points, such as the OHT (Off-Hull Tech) who filled a glove bag with helium and let it go (Spud Thunder got called out on that one), "Bunny Baseball", the enterprising mechanic who shot the rabbits in between the security fences with a "gun" made of a ball valve, pipe, and nitrogen tank which shot welding rods, and finally, the idiots who decided to pour Tide samples into the S1W spray pond...ah, good times.

quote:

Saw some posts below from some of those F'n NUKES talking about NTS CHAS. Anyone else train on the great flushable Rx?

If you did, come on, SPILL the beans.....

We all know that hafnium can be dispensed with....

There was a story told my several instructors about a "flushable" reactor for those students gullible enough to believe it. It was said to be an "exploding bolt" design that an uncontrolled reactor could simply be scuttled out the bottom of the ship and allow the in rush of sea water to cool down the plant while all propulsion was shifted to other means.

versions included a super secret force field that would not let water pass though it, to activate the the "exploding bolts": a big red button in the CO stateroom or having all scram switches to scram.

This may not be exactly what you were looking for but I thought it would be good for a chuckle considering that guys did show up to the boat believing the "exploding bolt" story and asked for checkouts on its design, which we quickly obliged and sent them for look ups to find the "flux capacitor" and and the "replacement/spare" reactor.

remind me some time to tell everyone about the portable air samples ordered by the galley watch captain and how to turn the TDU space into a snow globe. Oh, does anyone know about "Danger Nut"? Yes, the mechanics in NY were quite "adventurous" with risking life and limb.

BTW, I was a MARFin and that was one crazy reactor, especially all of the fill valves that were used to control the water levels an absolute ridiculous design but I heard the same reason from catherine0830 about the water controled reactor before it was modified.