Talk:S7G reactor

Reactor Operator
I stumbled on these Navy reactor pages by accident and found the information interesting. I was part of the original crew with MARF, going from initial testing of the new instrumentation for those reactor pumps, initial fuel loading, etc. I was the Reactor Operator who took the reactor critical for the first time and did scram testing from 50% and 100% power. Fun stuff back then!

Stbunten 04:23, 19 February 2007 (UTC)Steve Bunten


 * I qualified MO and ELT on MARF before going to Trident Design School across the lot at the S8G prototype. Thanks for the correction to my explanation of the tubes (gadolinium instead of hafnium) &mdash; I was working from twenty-some-year-old memory. Where did you after lighting off the MARF? ➥the Epopt 04:31, 19 February 2007 (UTC)

Thanks for the reply! Well, mine is 30+ year memories but having worked on it from the start I remembered that Hafnium wasn't used for control so I had to look up what else was used for neutron absorption and when I saw gadolinium I knew that was it. I left MARF prior to it ever getting students so never got to teach, leaving in May 1977. First I went to the USS Tunny (SSN682) out of Charlston that got transfered to Hawaii. After being there, I asked for a transfer to the USS R.E.Lee (SSBN601) as RC Division LPO. After getting out in '81 I went to college getting a degree in Computer Engineering and been living in Colorado since '85. Stbunten 04:49, 19 February 2007 (UTC)Steve Bunten


 * We missed by a little over two years then. I was at MARF in the winter of 1979-1980, then went to Groton in the initial increment of PCU No Name (SSBN-728), then went to sea on the first patrol of Ohio Blue. Out in '83, a year in civvie nuke plants (scary!), and now a Los-Angeles-based contractor working with NNPI. Welcome to Wikipedia! I hope to see your name in lots of article histories. ➥the Epopt 05:32, 19 February 2007 (UTC)

There have been a lot of stories going around the fleet about how the MARF plant came into being, the most prevalent saying that Rickover came up with the design after his Halfnium supplier wanted to jack up the price of components for control rods. Basically, he implemented the design to prove that he could run a safe, stable Naval Reactor without Halfnium control rods as a way of proving them wrong. Anybody know if there's any truth to this story? BTW, I'm a nuke EM just off the USS Ronald Reagan (CVN-76). 138.163.0.46 03:14, 11 September 2007 (UTC)

That is an interesting story and could well be true but I have to say that I never heard that from anyone while we were building MARF back in the mid-70's. I am amazed that even at this time there are folks in the Navy who even know anything about MARF 30+ years after it first went critical! It was an interesting concept--we used to say that you "flush the reactor" instead of the typical "scram". Stbunten 19:24, 7 November 2007 (UTC) Steve Bunten

Really bringing back memories of MARF here. My time at MARF was later than yours, 1986-87. Reported for Sparkle crew on S3G and D1G while waiting for my class to form at MARF. I think S3G was doing some maintenance and us NUBS were great sponges for rads to the nads cleaning the reactor bilge. Regarding why Rickover built MARF... we were taught that Rickover wanted a design the eliminated rod transients at scram. There were some cool inherent benefits that made the design safer than other designs, but the Navy did not deployed S7G due to issues with rolls and angles of the boat which would cause core water level variances. As far as reactor plant noise reduction goes... Rickover's sodium cooled design for the original USS Seawolf meant no main coolant pumps. But that design was scrapped, thank God. The navy finally obtained natural cooling flow to around 30% power with S8G using the safer water cooled design. But we did not revisit rod slam transients, and have stayed with the hafnium rods over the decades. I was the first in my class to qualify and was really proud of the different design, but had to start all over again once reported to my first boat. Y'all know the drill on that qualification. Thanks again for the memories. 25 March 2020, Guy McDonald --2602:306:3686:26B9:DCBB:97A:22F6:6895 (talk) 01:23, 27 March 2020 (UTC)