Re: SCRAM

[Keith Welch <welch@CEBAF.GOV>]

The standard story is Safety Control Rod Axe Man.  Can anybody verify this
nitpicky clarification? -- The story I heard  was that there was in fact
ONE "Safety Control Rod".  There were other "power" control rods which were
manually pulled and inserted.  The safety rod was apparently a "super rod"
which when inserted could offset all the positive reactivity inserted by
the power rods - with a safety margin.  The safety rod was hung by a rope
through a pulley above the pile, the rope tied to a wooden rail, and the
SCRAM fellow was ready with the axe.

Can anybody verify whether the terminology is still used - I seem to
remember reactor designs that incorporated "power" control rods and
"safety" control rods, which would seem to be a lingering use of the
original terms.

------------------------------------------
>And just to further cause thought, what is the real meaning of SCRAM? 
>
>[Tracy Replies ==>]  The story which I always heard was that 
>during the first "reactor" tests at U. Chicago, a set of control rods 
>were suspended from a rope and pulley arrangement and in the 
>event of a runaway reaction, the rope would be cut and all the 
>control rods would drop into the core shutting down the reaction.
>Fermi assigned one of his technicians the job of Safety Control 
>Rod Axe Man.
>
>
Keith Welch
Thomas Jefferson National Accelerator Facility
Newport News VA
welch@cebaf.gov
Ph: (757)269-7212
FAX:(757)269-5048