RE: Helicopter IBIS and Sr-90 sources

["Neil, David M" <neildm@id.doe.gov>]

Thank you.  It's not at all what I thought, but that's what a SWAG is all about. Releasing Y90 didn't sound right to me, but nothing else occurred to mind.

 

For those of you who don't want to wade through the technical terms, the pressure in the blades holds the source retracted, then when the pressure fails, the spring moves it to an exposed position, where it can be detected.

 

This allows qualitative monitoring of the pressure without the need of rotating couplings, either pneumatic or electrical.

 

Right?

 

Dave Neil



-----Original Message-----

From: Rick Orthen [mailto:rorthen@cecinc.com]

Sent: Wednesday, May 19, 2004 1:07 PM

To: 'Brian Rees'; radsafe@list.vanderbilt.edu

Subject: RE: Helicopter IBIS and Sr-90 sources 







The IBIS is manufactured by, and registered to, General Nucleonics, Inc. (Pomona, CA) under California Registration No. CA321D103G (see http://www.hsrd.ornl.gov/nrc/sources/pdf/03210103.pdf).  The registered limit is 500 microcuries Sr-90.



 



DEVICE TYPE: Helicopter Blade Failure Detection Gauge



 



DESCRIPTION:  The device consists of a cylindrical housing typically 5.1" long and 2.75" diameter which contains a bellows, a system of radial detents for the bellows assembly and an axial rod which houses the activity in the form of an Isotope Products Laboratory or Amersham Model GNI 12205 Annular Beta source. The distal end of the axial rod terminates in a coaxial disc and the proximal end terminates in a connector attached to the bellows. The distal end of the housing terminates in a steel reset button. The proximal end of the housing terminates in a base which attaches to the port of a helicopter rotor blade and exposes the proximal end of the housing to the pressurized center of the rotor blade. The interior of the bellows is sealed and maintained at a reference pressure. The bellows is spring loaded against the detents. In operation, the bellows is held compressed against the detents by the differential between the blade pressure and reference pressure. When the bello

ws is compressed the source rod is in a retracted position and is shielded by the housing. If blade pressure fails, the reference pressure in the bellows is no longer sufficient to hold the bellows against the spring. The spring acts to release the detents and the source rod is moved towards the distal end, exposing the source outside the shield. In this position, a Geiger-Mueller Detector mounted inside the upper fuselage senses the increased radiation field and signals a pressure failure to the cockpit display. In all detectors (GNI Model 122XX-1) a 0.01 microcurie Strontium-90 source is incorporated to provide a bias signal for fail safe



operation.



 



 



Richard F. Orthen, CHMM



Senior Project Manager



Civil & Environmental Consultants, Inc.



Four Triangle Lane, Suite 200



Export, PA  15632-9255



724/327-5200, ext. 231



www.cecinc.com <http://www.cecinc.com/>