Reference, Questions and Help > Lessons Learned
how hot is clean?
alphadude:
MARSSIM is a guide... the DQO process should drive your plans not MARSSIM which has become "religion in a box!"
Back to the topic, are u looking for signs of pollution or some thumb rules or risk limits to get the job done.
Shonkatoys:
Marssissms was intended for small one radionuclide facilities. To use it at large facilities with multiple radionuclides is a joke in my opinion. It is also a joke to use 1940's instrumentation to check facilities when there is 21st century technology available. But if you have regulators using 1940's technology to check 1940's technology I guess then clean is what you get away with and marssisms has so many loop holes the best bet is to just make up numbers ask for your money and hope you dont get caught. And if you do get caught then say I didnt survey there and help the regulator find a clean space. If the regulator is still not happy ask your client for more money to tell him the regulator is wanting me to more than marrsisms and get paid twice. Well eventually someone is going to catch on :). Then we will all have to use 21st century technology and have to do it right and be accountable. Until then party hard and chump the client with the 1940's technology and Marssisms.
alphadude:
well as you know humans are prone to error, and have an attention span of about 20 minutes on mundane tasks such as frisking.
usually the resistance to modern technology is the body shop mentality. YOU mean this will replace 15 techs? That is less money i can charge the customer if you use 3 techs and one machine!!! Look again at the cost? Its the same ole same ole...
the technology is high right now due to this body shop mentality. (horses were cheaper than cars if u remember and people were afraid of gasoline.) so, shonkatoys is right, its a statistical crap shoot. but as with MARSSIM and pigs, even a blind pig finds an acorn sometimes!
Shonkatoys:
Having been a senior tech before, the problem with surveys not being logged somehow as you do them is a human factor one. You have some techs who try to do the right thing and do accurate surveys. They usually work together because they take some pride in what they do. Then you have the dirt balls who are the lazy, stupid, latenight drunken party people, alcoholics, don't give a damn techs etc. They usually work together. Thats why I kept my own note book at work to write down exactly where I was, If you turned these people in you were the one punished not them. Thats why I kept my mouth shut and kept a log book. I have seen the so called snitches run off, not the ones that needed to be. I have found hot stuff on the 1940's technology when I went back to survey the scum tech areas. I never heard of one instance where the 21st century technology was found in error. There fore Marssisms is useless without 21st century technology in my opinion to log and map everything. The body shops have a hard time filling spots sometimes and will bring back people they know messed up before. Marssims and a Blind squirrel like alpha dude says will find a nut every once in a while. I myself trust in 21st century technology. So to answer the question how hot is clean? You have a few answers,
1. With dirtball techs with 1940's technology instruments that do not log data then it is what you can get away with with a straight face.
2. With good techs with 1940's technology instruments that do not log data it is pretty close to the set limits. However with this technology you can not survey as quick or get the good data of 21st century technology. You may get a few hundred readings a shift .
3. Dirtball techs with 21st century technology, As Donald Trump says, Your FIRED.
These instruments time stamps, photographs what you survey, calculates the background, etc. If this looks wrong you will probably work one more shift to document this and then> YOUR FIRED This is good for Marssisms and the whole nuclear industry!!!!!
4.Good techs with good up to date 21st century equipment take pride in what they do, and do not have to deal with dirtballs for long. They get great information and can get right at the limits set forth by the project. They get about 100 thousand or more readings a shift.
Well these are my answers, feel free to write more!!!
raymcginnis:
Cool! This topic took off!
I agree with some of this and disagree with other parts of the postings. I agree that you need people who care about their jobs. I worked a site once where I was supervising people who had never done HP work ever. They could care less about what they were measuring and we, the supervising HPs, could not make them care. It was frustrating.
I worked a job in the 1980s where all I did was frisk walls, floors and ceilings for months, 7days, 12 hours a day. I guarantee that I found way more than one acorn or one nut. I must be a special nut case myself, LOL.
We have all 20+ year people who all love their job and they are all good at it, including our contractor technicians. MARSSIM works fine for us. The NUREG calculations include the surveyor MDC factor to account for standard Human error. Nothing can account for people not caring about what they are doing though.
We have pretty decent equipment, but we still sometimes use 1" NaI detectors to back up our soil sample data (along with a modern GPS large detector system). But it works! The confirmatory regulator groups rarely find anything behind us.
As far as small one isotope facilities, I disagree. You can choose a surrogate isotope. If you base you scan MDC on that isotope and can do your calculations to prove that you can detect that isotope, then whole site is clean, you are set. The calculations for surrogates are in MARSSIM to tell you how to do this. I recently proved that all you have to do is the sum of fractions based on individual isotope MDCs. You come up with the same surrogate isotope MDC to do if you use calculations with the MARSSIM equations. We have about 16 isotopes for a given facility, but I alway pick the predominate gamma emitter. It works every time.
We also use our old pre-MARSSIM statistical method as a backup. We created this program before most people even knew what D&D was. It uses a statitical method called cumulative probability. We created software and it is recently improved. You can get it as freeware from my website: http://www.radprocalculator.com/software.aspx
It is called Cumulative Probabbility Plot
It is a plotting program that uses these statitical methods and is useful not only for releaseing sites, but interpreting large sets of data, whether nuclear or not (building widgets).
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