REM-500 Neutron Survey Meter (FarWest Technology)

[RP Instructor]

Folks:

I'm in need of some input on the REM-500 Neutron Survey Meter from folks that have used the instrument. The type of input I'm looking for is:
a. What did you think of the instrument?
b. What are the "pros" and "cons" of the instrument?
c. How would you compare it to the REM-Ball?

Any input would be appreciated. Thank you.

[Shawnee Man]

Here are some of the obvious:

Pros

1) Light weight.
2) Has self source check.
3) Compact.

Neg

1) I always liked to see a needle responding to an increase than a digital readout.
2) Rem 500 will not help you to get big muscles!

Unknown

1) I have never used at power plant only at DOE facility. I know that the rem balls worked fine when I used them at the power plants.
2) Costs: I have not compared the two.

I hope this helps alittle.

[moke]

Summer School Teacher,

Be sure that the Neutron Detection device will cover the Neutron Energy Spectrum specified by your facility.

Have an Awesome Week,

Moke

[retired nuke]

The REM500 is better than the RemBall for detecting neutron streaming thru bioshields at BWRs. They are a helluvalot lighter, and once you get used to the display, are real comfortable to use.

[Druid]

They are light weight and the digital display automatically switches range. But they cost 3 to 4 times what a rem ball costs.

They do have an attached source (Cm-244 alpha, about 1 microCurie) which checks the energy calibration of the unit. the meter basically is a neutron spectroscopy unit, it catagorizes each neutron event by energy and applies the appropriate quality factor.

The problem with the attached source is that it is a source, so the whole unit has to be controlled as radioactive material.

I have only used them at DOE non-reactor facilities and with the number and types of surveys we have done a rem ball would have been just as good and saved alot of money. BUT if you are doing a lot of surveys and/or having to hold the unit in various positions for extended times (like shield surveys) then the REM 500 may be worth the extra cost.

[McCrank]

The facility I work at purchased five units and put them into service about a year ago. We are currently down to one working unit. They are nice to carry but don't seem to be as durable as the the old Ball of Bear Fat.

[Scorpio51]

We have one at HNP.  Nice and light compared with a remball.  Works great for spent fuel shipments.  We've tried it in the RCB at power and it doesn't like the heat. 

[Silverthorn28]

The facility I work at purchased five units and put them into service about a year ago. We are currently down to one working unit. They are nice to carry but don't seem to be as durable as the the old Ball of Bear Fat.

I share with you on this. The REM-500 is really prone to damage.
Our people tend to like Ludlum 2363 with a Prescila probe.

[spentfuel]

a. What did you think of the instrument?

Light weight easy to use not to durable

b. What are the "pros" and "cons" of the instrument?

Pros (see A) plus I also believe its spectral

Cons (see A) plus because of the cal source Cf 252 in some plant neutron spectrum's it may not give an accurate reading (or thats what I have heard)

It does contain an optional Cm 244 internal check source so it has to be handled as ram and shipped as such

It contains propane gas in the detector but I have also heard this is not a shipping issue but have seen no documentation which supports that.


c. How would you compare it to the REM-Ball?

The ball is heavy the 500 is not.

The ball has a susceptibility to static build up that makes the needles go Nana's the 500 is digital

The ball has a Bf3 detector which is classified as a poisonous gas there is suppose to be some DOT exemption for the detector but again I have not seen one, the 500 if equipped with the source is class 7 without considering the propane

hope that helps

sf

[Boilermaker]

Pros: Light weight, easy to use, has been in industry over 10+ years.

Cons: digital display, very shock sensitive, but can be mitigated by "zero-ing" it.  If bumped, it can jump real fast and high, but like I said, you can zero it to start over.  Nice backlit (25 seconds) and good integrate modes.  Newer models are now called Rem500B and check sources are no longer being sold attached to meter. 

My 0.02
In my opinion, this meter is not a replacement for the remball, but an addition or side-by-side companion to it.  We use it as a backup to the remball or when entering fields that are known/routine b/c of its light weight, compare to lugging the 18 lbs remball.  Also when implementing any new instrument, it's always an uphill battle to get everyone on board into using it over something that they have used pretty much all their career.  Hope this helps.     

[Dave Warren]

Is there anyone that has a working procedure for this instrument that I can have?
I have heard that Ginna and Nine Mile have one.
Can anyone help?

[GLW]

Is there anyone that has a working procedure for this instrument that I can have?
I have heard that Ginna and Nine Mile have one.
Can anyone help?

Writing your own or heavy plagiarizing?

If the former start here,...

http://www.fwt.com/hpi/support/REM500B_REVB3.PDF

If the later, cut me a PO and I'll do it for you,....

[nickscott13]

Correct me if I am wrong, but is the Rem 500 the instrument with a 10 second, 30 second, and 60 second count time with the 60 second being the most accurate of the 3?

We (DAEC) used these for our last Dry Cask Storage campaign and actually went back to using the Rem Ball because we were picking up too much dose trying to get accurate Neutron dose rates on loaded casks.  Sure they were light weight, but you had to take 1 minute readings 13 times per cask, causing us to pick up way to much dose.  The rem ball response time is 5-10 seconds and was much more ALARA.

We borrowed them from a sister plant and sent them right back after the campaign and said we would never use them again.  For day to day neutron surveys they would probably work great, they just arent very ALARA.

Nick

[Dave Warren]

The house wants to use them in conjunction with the Rem Ball, I am told. We are using them for Dry Cask also.

[SpyCat]

At SONGS' ISFSI, techs didn't like that Remballs would "click" in areas that should have zero neutrons.  Since there were never-used REM500s on the shelf, I saw to get these recalibrated & put into service.  I recommend using protective padding on the meter for doinks during field use.
The REM500 is way accurate, but you get best survey data from 2 minute Integrate Mode counts; data is not so reproducible when using its Dose Rate mode though.  Since ISFSI surveys require numerous points it was not time-effective nor ALARA for the techs to use its integrate mode for surveys. 
Alas, the fuel transfer at SONGS was suspended (Fall 2018) not long after we started using the REM500 there.