Wednesday 15^th November 2006
National Physical Laboratory

Present:

 

Chairman:		Steven Judge		National Physical Laboratory
Acting Secretary:		Clare Lee		National Physical Laboratory
		Jen Barnes		AMEC NNC Ltd
		Graham Bass		National Physical Laboratory
		John Bennett		DSTL
		Reg Bosley		RWE Nukem
		Derek Brazer		AWE
		Peter Burgess		National Physical Laboratory
		John Caunt		John Caunt Scientific
		Oliver Caunt		John Caunt Scientific
		Robin Crosse		Thermo Fisher Scientific
		Bill Croydon		Radiation Watch Ltd
		Tim Daniels		HPA, Radiation Protection Division
		Paul Deacon-Smith		St Thomas's Hospital
		Denise Delahunty		RRPPS, Birmingham
		Graham Denton		Centronic Ltd
		Geoff Druce		AWE
		Jonathan Eakins		HPA, Radiation Protection Division
		David Gallacher		St Thomas's Hospital
		Andy Galpin		Nukem
		Julian Ginniver		UKAEA, Dounreay
		Rikki Glover		Lab Impex
		Ian Goldsmith		Nukem
		Heather Hale		Dungeness B Power Station
		Paola Hayes		HMS Sultan
		Chris Hill		Thermo Fisher Scientific
		Michael Hodgson		Thermo Fisher Scientific
		Victoria Howard		Heysham Power Station
		Bob Johnstone		Berthold Technologies (UK) Ltd
		Ingo Kölln		RADOS Technology
		Alan Lewis		James Fisher & Sons plc
		Sean Marriott		BAE Systems Ltd
		Duncan McClure		HPA, Radiation Protection Division
		Jan McClure		HPA, Radiation Protection Division
		Roy Mooney		Northern Ireland Medical Physics Agency
		Alec Morton		James Fisher & Sons plc
		Steve Newton		BIL Solutions
		Trevor Nicholls		Lab Impex
		Mairin O'Colmain		Radiological Protection Institute of Ireland
		Martin Palmer		National Physical Laboratory
		Max Pottinger		Thermo Electron Corporation
		Dave Rayner		National Physical Laboratory
		Mike Renouf		British Nuclear Group
		Tony Richards		Consultant
		Jon Silvie		BAE Systems Ltd
		Keith Simmons		MoD Nucleonic Calibration QP Committee
		John Simpson		RWE Nukem
		Bill Snooks		Pycko Scientific Ltd
		Dan Strickland		BAE Systems Ltd
		Sinclair Tait		RWE Nukem
		Rick Tanner		HPA, Radiation Protection Division
		David Thomas		National Physical Laboratory
		Simon Threadingham		DSTL
		Jill Walker		RCD Lockinge
		Jonathon Wardle		AWE
		Graham Whish		Addenbrooke's Hospital
		Malcolm Wilson		National Physical Laboratory
		Mike Woods		IRMC

32.1  Welcome

Steven Judge (NPL) welcomed delegates to the 32nd meeting of the IRMF. Steven outlined the agenda for the meeting and informed members of an exhibition located in the Reception area.

Duncan McClure (HPA), requested that the minutes of the 31st meeting were amended to record an action on Steven Judge (rather than on Duncan), to write to Graham Hart (Assessment Secretary for RPA2000) regarding the re-instatement of instruments specialists. Steven confirmed that he had written to Graham and offered the assistance of the IRMF in re-instating this certification. There were no other amendments to the minutes and they were agreed to be an accurate record of the meeting.

There were no further matters arising.

32.2  Criticality Incident Detection

Geoff Druce presented an overview of criticality incident detection systems. He began by defining criticality and went on the cover the requirements of any detection system; the primary purpose being to alert personnel to evacuate when necessary. Geoff described the various detector types that can be used and the different warnings that may be triggered. He also covered the principles of safety assessment and the testing of a criticality incident detection system.

Geoff informed the members of a draft Good Practice Guide that had been written by the nuclear industry with the aim of agreeing a common approaching to the examination, maintenance, inspection and testing these systems in the UK. Geoff asked Steven Judge to consider the IRMF adopting that draft for publication as an NPL Measurement Good Practice Guide.

View Geoff Druce's presentation ( PDF 21 KB)

32.3  Security Measures for High Activity Sealed Sources

Alan Husher (National Counter Terrorism Security Office) outlined the role of NaCTSO and its relationship with central government, the security services, the Police Force and Counter Terrorism Security Advisers (CTSAs).

The responsibilities of NaCTSO included:

• Co-ordination and training of CTSAs
• Identification and promotion of good practice in counter terrorism
• Assisting with the development of security policy
• Advising on security for a range of hazardous materials

Alan outlined some of the techniques used to categorize radioactive material and the security measures and emergency procedures appropriate for each category. In response to queries from the members, Alan was clear that one aim of NaCTSO was to ensure a consistent standard of security for radioactive material while maintaining a flexible approach that allowed for any difficulties and issues of specific sites.

Alan's presentation is not available to download. A report entitled "Security Requirements for Radioactive Sources" is available from CTSAs or NaCTSO. Members with specific security concerns are invited to contact Alan Husher at nactso@btconnect.com.

32.4  Impact of the new ICRP Recommendations on Practical Radiation Protection

Rick Tanner (HPA) gave a presentation on the proposed changes to the ICRP dose quantities and weighting factors on behalf of the ICRP committees working on their revision. Rick said there would be effectively no change to operational Health Physics; however, there would be changes to:

• Effective dose
• Radiation weighting factors for neutrons and protons
• Tissue weighting factors

Rick recommended the IRMF request another update from the ICRP committees in November 2007 when further progress has been made.

Awaiting Permission to Publish Rick Tanner's presentation

32.5  The Effect of Large Area Source Non-Uniformity

Ian Goldsmith (Nukem) reported that he had undertaken a detailed investigation of the uniformity of Nukem's 150 x 200 mm surface contamination sources. As some of their sources had been supplied in two halves, it had been unclear if the uniformity stated by the manufacturer had applied to the whole source or to each half.

Measurement had been made in 25 x 25 mm areas over the surface of each source, with and without the presence of a b mask (to eliminate g penetration). Ian presented the results as charts of the distribution of emissions. Ian concluded that their 137Cs and 234U sources did not meet the GPG14 (and hence ISO 8769) criterion of the uniformity being less than 10%.

View Ian Goldsmith's presentation (  PDF 197 KB)

Mike Woods (IRMC) stated that UKAS would expect any competent laboratory to determine the uniformity of their sources themselves. Pete Burgess (NPL) stressed that users need to maintain pressure on the manufacturers to supply more accurate data with the sources. Jon Wardle (AWE) made members aware that his measurements of customer 14C sources had shown they had different spectra.

32.6  Investigation into Deviant Responses to Surface Contamination Comparison

Pete Burgess (NPL) reminded members that the last surface contamination comparison exercise (2004) had demonstrated little improvement since the previous exercise (2000). It had been decided that, rather than continuing with the cycle of comparison exercises, there would be an investigation into why discrepancies in the results had arisen. Pete presented a list of the possible causes of the discrepancies and asked the members to contact him if they had any further ideas.

View Pete Burgess's presentation ( PDF 95 KB)

Mike Woods (IRMC) said that he was pleased this investigation would take place but that some of the reasons for deviant results were already known and the findings of previous work should be included. Mike added that he thought 5 or 6 years between each comparison exercise was too long and asked how UKAS accredited laboratories should validate their ongoing performance until the next exercise. Pete Burgess (NPL) stated that UKAS validation was not the main purpose of these exercises. Denise Delahunty (RRPPS) suggested that the UKAS labs could undertake a comparison exercise of their own.

32.7  Fibre Technology in Contamination and Clearance Measurement Devices

Ingo Kölln (RADOS Technology) gave a brief history of the evolution of whole body monitor technology. He went on to describe a new whole body monitor developed by RADOS that utilised plastic scintillators and multi-channel photo-multipliers rather than traditional gas flow proportional counters. Advantages of the new monitor included:

• Improved geometry
• Improved detection efficiency
• Easy to maintain, repair and replace detectors
• Low failure rate of PM tubes (and fewer of them)

The TwoStep^TM-Exit monitor was available to view in the exhibition.

View Ingo Kölln's presentation ( PDF 3.3 MB)

In response to Mike Renouf's (British Nuclear Group) question about when the system might be ready for use in detecting as, Ingo said they were already working on a discriminator.

32.8  Medical X-ray Intercomparison

Denise Delahunty (RRPPS) informed the members that significant progress had been made in the organisation of the proposed comparison of diagnostic X-rays. A draft protocol had been prepared and was to be tested by Denise on a clinical set to ensure it was realistic. The exercise would involve the circulation of a Keithley tertiary standard ionisation chamber (loaned by RRPPS) around approximately six centres. Measurements would be made with the tertiary standard and then with the centre's own instrument(s) using their usual technique. Denise defined the qualities at which measurements would be made.

View Denise Delahunty's presentation ( PDF 43 KB)

32.9  Update from the EPD Working Party

On behalf of the working party, Jan McClure (HPA) updated the meeting with progress on the Measurement Good Practice Guide being written for Electronic Personal Dosimeters. Most of the technical issues with the document had been resolved by the IRMF meeting in May 2006. Effort since then had been focussed on drafting the document. John Bennett (DSTL) volunteered to help Jan to complete the draft in time for the IRMF meeting in May 2007

32.10  Review of GPG14

Pete Burgess (NPL) listed the many comments and suggestions for revisions to GPG14 that had been received. The next stage was for NPL to review the suggestions and, where necessary, circulate the suggestions for further discussion amongst the community. Pete hoped a draft document would be circulated before the next meeting in May 2007.

View Pete Burgess's presentation ( PDF 191 KB)

There followed a discussion about the source to detector separations that are used for calibrations: a number of members stated the separations used in their own establishments, these varied between 3 mm and 10 mm. Mike Woods (IRMC) made the point that a lot of work had already been undertaken on the effects of source to detector separation and effort should be made to collate that data into a database to ensure it was not lost. Jam McClure (HPA) stated that HPA Report R232 was relevant. [D R McClure et al. Evaluation of some Hand-Held Instruments for Measuring Radioactive Surface Contamination (1990) ISBN 0-85951-319-X]

32.11  Briefing from BSI Working Group 17

Tony Richards (Consultant) updated the meeting on the recent activities of the Working Group 17 whose remit was "Radioactivity Measurement". Information on the current status of each part of the relevant ISO documents being reviewed was given. In particular, Tony informed the members that the draft of ISO7503-1 that had been presented to the IRMF meeting in November 2005, had been abandoned; a new draft was underway and many changes were expected before it would be presented to the IRMF again.

Clare Lee (Secretary) asked Tony to investigate the possibility of adding links from the IRMF website to draft documents available for consultation on the BSI website.

32.12  NPL Programme Formulation

Dave Rayner (NPL) reminded the meeting that the 2007 - 2010 NMS Programme for Ionising Radiation was being formulated at present and encouraged the members to provide input. A period of consultation was just coming to an end however, questionnaires were still available online if members still wished to comment at this stage. Dave listed the top ten user specific needs for Radiation Protection and Environment & Decommissioning that had been identified via the questionnaires and user consultation meetings to date. The next steps included preparing a Draft Programme of projects for review by the Measurement Advisory Committee. The next period of public consultation would be March to June 2007, members were urged to submit comments.

View Dave Rayner's presentation ( PDF 114 KB)

32.13  Any other business

Jon Wardle (AWE) described a project he was planning to design a new detector to perform neutron dosimetry after a criticality incident. Jon had funding for the project and was looking for partners. He stated that little work had been undertaken in this field since the '70s and much expertise had been lost. NPL offered to supply neutron fields if they were needed for testing the new detector in the future. Anyone else interested in the project should contact j.wardle@awe.co.uk.

Mike Renouf (British Nuclear Group) asked the members for their opinions on the suitable periodicity of function checks on changing room equipment. The consensus of the meeting was that they should be performed weekly to monthly depending on: the frequency of use of the equipment; the frequency of breakdowns; the degree of confidence in the equipment, and, the intelligence/complexity of the equipment.

Details of a number of relevant forthcoming events were communicated to members. A manufacturer's exhibition was held in the reception area over lunch

The next meeting will be held on 9th May 2007.

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