[ RadSafe ] Question about neutron source Pu238-Be

[Philip Simpson]

Nicolas,

We had two Pu238Be sources manufactured by Mound in the early 60's They were designed to screw together in a dumbell configuration roughly 1.5" diameter and 5" long.  Total original Pu-238 activity was 84 Ci.  On June 27, 2003 we measured dose rates of 41 mrem/hr gamma and 250 mrem/hr neutron at 1 meter.  The dose rates were measured with an Eberline Ro-20 and Ludlum 9" REM ball.

Hope this helps.

Phil Simpson
Assistant Reactor Manager (Ret.)
Ford Nuclear Reactor
University of Michigan


On Aug 25, 2011, at 1:05 AM, Ted de Castro wrote:

> In the US these sources were made by MOUND Laboratory - and I can assure you that they have NO information on them.
> 
> They were custom made and thus came in many sizes usually characterized by the Curies of PU or the neutron emission rate in 4 pi.
> 
> If you can tell me either of those - and the date of course - I can calculate the approximate neutron dose rate now.  Gamma you'll just have to measure - I have no data on that.
> 
> On 8/24/2011 6:22 AM, BRISSON Nicolas wrote:
>> A colleague of mine will carry out assessment on multiple neutron
>> sources : dose rate measurements, activity assessment and packaging for
>> transport and disposal.
>> 
>> Most of these sources are Pu239-Be, Am241-Be or Ra226-Be and we have
>> experience and documentation about them.
>> 
>> But one of the source is a Pu238-Be and we don't have any information on
>> this type of source. The provider is not known and the source is 50
>> years old.
>> If anyone has information about firms that produced this type of source
>> and possibly values for gamma and neutron dose-rate, it would help us a
>> lot to prepare for this operation.
>> 
>> Thanks in advance,
>> 
>> Nicolas Brisson
>> IRSN/DEI/SIAR
>> route du Panorama
>> 92262 FONTENAY AUX ROSES
>> tel : +33 1-58-35-87-24
>> por :  +33 6-08-76-55-32
>> 
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