Re: transportation event

[John Jacobus <crispy_bird@YAHOO.COM>]

Well, I guess that after 30 years, ammo boxes have

proven they are adequate.  



--- William V Lipton <liptonw@dteenergy.com> wrote:

> This arrangement is generally known as "scab

> shielding," i.e. shielding which is  not an integral

> part of the packaging.  I

> generally avoid it, for two primary reasons:  (1) It

> often compromises package integrity.  2.  The

> shielding may fail within the

> package, resulting in a dose rate increase.  With

> many radionuclides, the dose rate, not the quantity

> is the limiting condition

> for an RQ shipment.

> 

> I remember a training class where a class exercise

> involved determining the maximum quantity of solid

> Co-60 that could be shipped

> LQ.  The activity limit is 10.8 mCi.  With all of my

> usual diplomatic skills, I challenged the instructor

> to find a "strong tight"

> package for that quantity of Co-60 which would meet

> the 0.5 mR/hr dose rate limit.  (The unshielded dose

> rate from a Co-60 point

> source of 10.8 mCi is ~150 mR/hr at 1 foot.)

> 

> In a situation such as this, there's a great

> temptation to add shielding to the package to

> achieve dose rate compliance.  I would

> generally avoid this.  Possible solutions:  use a

> bigger package, with the material securely centered

> in the package; use a

> shielded package; or ship as NOS, rather than RQ.  I

> suspect that an ammo box is not an adequate package

> for material in a lead

> pig, especially if it were dropped on a top corner.

> 

> . . .





=====

+++++++++++++++++++

"Eternal vigilance by the people is the price of liberty and . . . you must pay the price if you wish to secure the blessing."

Andrew Jackson



-- John

John Jacobus, MS

Certified Health Physicist

e-mail:  crispy_bird@yahoo.com



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