RE: Radiation Safety System

["Andy Hurst, TRIUMF Operations" <hurst@erich.triumf.ca>]

Subj:	Radiation Safety System

Further to what has been said by others, you should also define 
a test procedure that is to be done regularly (after any major 
maintenance period) to ensure that all interlocks are functioning.  

It may occassionally be necessary to defeat some interlocks - 
there should be a documented procedure.  At TRIUMF, the 
safety system includes an input terminal panel which supplies the 
status inputs to the safety computer system.  Some defeats are made 
by jumpering (red coloured jumpers) contacts in this panel.  This 
panel must be checked by the safty operator at the beginning of 
each shift.  A timer system must be reset at the time the interlock 
status is checked.  If the operator forgets to check, and alarm 
is issued.  

Any time we make a defeat, it is written up on a form which all 
operators are required to read and initial.  This gives the essential 
information - reason for defeat; location of device; nature of defeat; 
and alternative protection - eg another device or procedure.  

good luck, 

Andy Hurst, TRIUMF Operations.