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Re: AW: PCM-2 turning off detectors by itself yet showing "green"light (operational)

To: "Franz Schoenhofer" <franz.schoenhofer@CHELLO.AT>
Subject: Re: AW: PCM-2 turning off detectors by itself yet showing "green"light (operational)
From: Pmink@bnfl-ettp.com
Date: Wed, 16 Jun 2004 08:03:04 -0400
Cc: radsafe@list.Vanderbilt.Edu
Reply-To: Pmink@bnfl-ettp.com
Sender: owner-radsafe@list.Vanderbilt.Edu

Franz -

The possible causes we've come up with are a power surge/power

failure/"dirty" power, hard drive error, or just a general computer

"glitch". The units are in an air conditioned enclosure, but it is not

completely sealed as the entrance and exit have clear plastic refrigerator

strips hanging in front of them.

Thanks -

Paul J. Mink, SAIC

Lead Radiological Engineer

BNFL-ETTP RADCON K-1550-T trailer

Office (865) 576-2123

Fax (865) 241-0452

Alpha pager 1-800-622-6576 (http://www.arch.com/message/)

Smile...it makes people wonder what you're up to.

"Franz Schoenhofer" <franz.schoenhofer@chello.at>

06/15/2004 02:14 PM

To: <Pmink@bnfl-ettp.com>, <radsafe@list.vanderbilt.edu>

cc:

Subject: AW: PCM-2 turning off detectors by itself yet showing "green" light

(operational)

What about a temporary and short power failure?

Franz

-----Ursprüngliche Nachricht-----

Von: owner-radsafe@list.vanderbilt.edu

[mailto:owner-radsafe@list.vanderbilt.edu]Im Auftrag von Pmink@bnfl-ettp.com

Gesendet: Dienstag, 15. Juni 2004 18:05

An: radsafe@list.vanderbilt.edu

Betreff: PCM-2 turning off detectors by itself yet showing "green" light

(operational)

Greetings!

We had an interesting problem happen recently and I thought I would check

with the Radsafe community to see if anyone's had a similar problem. A

PCM-2 apparently disabled all 34 alpha and 34 beta channels by itself, yet

it still appeared to the workers that it was operational, i.e., had the

green light. It would go through the motions of performing a personnel

survey and indicate that the person had nothing over the limits on them,

but all detectors were inactive. The Instrumentation RCT found the PCM in

this disabled state when he went to perform a source check on it. He then

went to pull the PCM log data at my request so we could determine the

approximate time frame this happened. After pulling the data file

(involves exiting the PCM program to DOS), the RCT restarted the PCM

program and the unit went back to the state it was in prior to all

channels being turned off. We've investigated this and have rule! d out

operator error and sabotage. The high-level password required to access

the menus to turn off the detectors had just been changed and only three

Instrumentation RCTs had it.

BNFL had Thermo Eberline modify the PCM program last year so that a tech

couldn't accidentally turn off all the detector channels with a single

keystroke. This accidentally happened last year when one of the field

RCTs, trying to help out, accidentally did this. The menu options to turn

off a single detector channel and to turn off ALL detector channels are

right next to each other in the menu and the screens for each of them look

exactly alike, except one says "all detector channels." The modification

Thermo made for BNFL requires that each detector channel has to be

individually turned off, so someone would have to send a lot of time to

turn off a total of 68 channels. The last incident was issued as a

"Lessons Learned" through the DOE system, which warned that the PCMs will

still show a green light (i.e., appears to be operational) even if all

detectors are off.

Anyone seen anything similar to this?