Wednesday 18^th May 2005
National Physical Laboratory

Present:

Chairman:		Steven Judge		National Physical Laboratory
Secretary:		Clare Lee		National Physical Laboratory
		Arzu Arinc		National Physical Laboratory
		Sonia Ashmore		A Consulting
		Duncan Aston		High Technology Sources
		John Bennett		DERA RPS
		Derek Brazer		AWE
		Peter Brember		Environment Agency
		Peter Burgess		UKAEA
		Grace Carloan-Rees		University Hospital Wales
		Western Case		GE Healthcare
		Robin Crosse		Thermo Electron
		Bill Croydon		Thermo Electron
		Piers de Lavison		National Physical Laboratory
		Julian Dean		National Physical Laboratory
		Denise Delahunty		RRPPS, Birmingham
		Geoff Druce		AWE
		Mark Edwards		Lancaster University
		Neil Foreman		Centronic Ltd
		David Gallacher		St Thomas’s Hospital
		Julian Ginniver		KAEA Dounreay
		Paola Hayes		HMS Sultan
		Norman Heffernan		Radiation Protection Service
		Chris Hill		HPA, Radiation Protection Division
		Guy Hunter		MESH IPT
		Duncan Jackson		Enviros Consulting
		Simon Jerome		National Physical Laboratory
		M Johnstone		BIL Solutions
		Phil Kruse		Enviros Consulting
		Ian Lavigne		Innovision Research and Technology plc
		Vic Lewis		National Physical Laboratory
		Will Macivor		Johnson Controls
		Andy Main		Johnson Controls
		Shaun Marriott		BAE Systems Ltd
		Ray McConnell		BIL Solutions
		Roy Mooney		Northern Ireland Medical Physics Agency
		Ross Morgan		HPA, Radiation Protection Division
		Mairin O’Colmain		Radiological Protection Institute of Ireland
		Martin Oliver		Lab Impex
		Hilary Phillips		National Physical Laboratory
		Max Pottinger		BIL Solutions
		Dave Rayner		National Physical Laboratory
		Tony Richards		Consultant, Leeds
		Phil Royston		Innovision Research and Technology plc
		Sue Ryan		New Cross Hospital
		Joanne Shaw		HPA, Radiation Protection Division
		Mark Sheppard		BIL Solutions
		Keith Simmons		MoD Nucleonic Calibration QP Committee
		John Simpson		RWE Nukem
		Jeff Slade		AWE
		Bill Snooks		Pycko Scientific
		Dave Taylor		National Physical Laboratory
		Bob Thomas		Avonwood
		Chris Thomas		Avonwood
		Janet Townsend		PA Consulting
		Russell Trueman		DERA RPS
		Eddie Veater		UKAS
		Jon Wardle		AWE
		Dave Williams		HPA, Radiation Protection Division
		Eliot Williams		UKAEA

 

29.1 Welcome

On behalf of NPL, Steven Judge welcomed members to the Twenty Ninth Meeting of IRMF. For the benefit of a significant number of new members and new speakers, he outlined the aims and nature of the IRMF.

29.2 Apologies for absence

Apologies had been received from:

Reg Bosley		RWE Nukem
Tim Dollery		Mainance International Ltd
James Grand		Berthold Technologies Ltd
Duncan McClure		HPA, Radiation Protection Division
Jan McClure		HPA, Radiation Protection Division
David Rawlings		Newcastle General Hospital
Mike Renouf		British Nuclear Group
Graeme Taylor		National Physical Laboratory

 

29.3 Approval of Minutes of Twenty-Eighth Meeting, 26 November 2004

The minutes were agreed to be an accurate record of the meeting.

29.4 Matters arising

Steven Judge reported that the following actions from the last meeting had been completed:

• The minutes of the 27th meeting had been amended as agreed and put on the website;
• Measurement Good Practice Guide 49 “The Assessment of Uncertainty in Radiological Calibration and Testing” had been updated on put onto the website at http://www.npl.co.uk/irmf/. Vic Lewis and the other authors were thanked for their efforts to update this guide.

The Working Group reviewing GPG 14 “The Examination, Testing and Calibration of Portable Radiation Protection Instruments” had not met since the last IRMF meeting. It was agreed that Clare Lee would arrange a meeting to be held in the near future. Two more sets of comments on the guide had been received.

Steven Judge stated that the current Ionising Radiation programme included funding for the production of two Measurement Good Practice Guides. Some funding had already been allocated to support a guide on Air Monitoring however the remainder was available for whatever was considered to be the next highest priority. The members were clear that a guide on Electronic Personal Dosemeters was very important. Steven agreed that he would approach the programme managers to request the funding. Assuming funding could be secured, a working group was elected, this comprised:

John Bennett		DSTL
Derek Brazer		AWE
Peter Burgess		UKAEA
Bill Croydon		Thermo Electron
Chris Hill		NRPB
John Simpson		RWE Nukem

Steven Judge announced that Rebecca Nutbrown and Bob Angliss had agreed to represent NPL on the working group for the proposed IRMF/IPEM comparison of medical X-ray qualities. The working group could now arrange their first meeting to determine the scope of the exercise.

Steven Judge reported that a full review of the IRMF catalogue had commenced. Facility owners had been contacted and asked to review/update their entries as necessary; 9 organisations were thanked for having done this. Steven urged the remaining organisations to review their pages otherwise NPL would have to withdraw them from the catalogue.

At the 27^th IRMF meeting, members had asked if it would be possible to set up a bulletin board for discussions on the IRMF homepage. Clare Lee had reported back to the 28^th meeting that this had not been possible due to the NPL network servers in use at that time. However, Dave Taylor (NPL) had since been working on the possibility of the bulletin board being hosted by an external website and was now ready to pilot his system with a small group of users. The Secretary proposed that the medical comparison working group would be appropriate for this; their opinions on the system would be reviewed before the next IRMF meeting.

29.5 Surface Contamination Monitoring Comparison

Clare Lee outlined the scope of the exercise for the benefit of new members. She reported that the measurement phase of the exercise had finished and the working party had analysed the results; a summary of the results were presented. A draft report had been written by Sean Collins (NPL) and was presently being checked before publication in the next month or two. Clare thanked the participants and the working party for their efforts.

View Clare Lee’s presentation (pdf - 231kB)

Steven Judge (NPL) announced that the IRMF already had funding to conduct a fourth surface contamination exercise by September 2007 and asked for members to volunteer to sit on the working group; the following members were elected:

John Bennett		DSTL
Denise Delahunty		RRPPS
Chris Hill		NRPB
Max Pottinger		BIL Solutions
John Simpson		RWE Nukem

NPL would provide the secretariat for the working group and would organise the first meeting.

Clare continued that there had been a lot of discussion recently amongst the various calibration laboratories about the techniques used to determine the β emissions from reference sources of radionuclides that also have significant photon emissions (eg. ¹³⁷Cs). The method used at NPL was to measure the total response from the front face of the source and then subtract any photon emissions detected from measurement of the back face of the source (the backing plate of the source is sufficiently deep to prevent particulate emissions from escaping the back of the source). The problem with this technique was that it was impossible to differentiate between actual photon emissions and bremsstrahlung generated by the attenuated β emissions, leading to a large uncertainty. Jeff Slade and Jon Wardle (AWE) agreed that this method was not very accurate.

A discussion on the homogeneity and filtration of reference sources followed. Two organisations said they’d been disappointed after ordering new sources because the homogeneity had not met their requirements of <10%. An additional issue had been confusion over the purchase of photon reference sources and whether or not the sources were filtered (to eliminate particulate emissions). Members were advised to be very clear when purchasing reference sources from manufacturers to ensure that if Class 2 sources (as defined in ISO 8769 –1 (for α and β) or –2 (for photons)) were required then the order clearly stated this.

29.6 Gamma Monitoring Comparison

Martin Palmer (NPL) was unable to attend the meeting; Clare Lee gave the following report on his behalf. Significant progress had been made by Graham Bass (NPL) and Duncan McClure (HPA) on the protocol for the exercise, once complete this would be featured on the IRMF website. Four organisations had registered to participate however more could be accommodated and registration forms were made available. The exercise was expected to begin in Summer/Autumn 2005.

Registration form for Fifth Gamma Monitoring Comparison (pdf - 79kB )

29.7 EC Recommendation on the Reporting of Discharges Below the Limit of Detection

Phil Kruse (Enviros Consulting) informed the meeting of a new EC Recommendation on the reporting of discharges. The Recommendation applied to all civil nuclear sites (power stations and reprocessing plants) but this could be extended if the Recommendation became a directive in the future. Amongst its key features, the Recommendation allowed:

• The decision threshold to be conservatively reported as half the detection limit
• The results of measurements made below the decision threshold to be reported as half the value of the decision threshold
• If all measurements made were below the decision threshold, then a value of zero could be reported.
• Calculated values could be used in place of measured values where similar levels of accuracy could be achieved.

Enviros were conducting a project funded by DEFRA to determine the approaches currently used across industry and other radiological users in the UK to report discharges at or below the limit of detection and to propose a new method for the future. Nearly 30 different types of organisation, including providers and users of the data were contacted and two workshops were held to obtain views and opinions. Enviros would welcome further comments on the Recommendation.

View Phil Kruse’s presentation (pdf - 392kB)

29.8 Detection Limits for Decommissioning

Dave Williams (HPA) presented the findings of his work on the determination of Minimum Detectable Activities (MDAs). Detector characteristics, radionuclide characteristics, background radiations, survey technique and environmental conditions were amongst the factors considered. The HPA had developed its own model to calculate MDAs, the output of which was compared with the results of actual measurements of point sources and predicted MDAs calculated using the MARSSIM* approach. A method for determining Maximum Missable Activities was also presented.

*MARSSIM is the US Multi-Agency Radiation Survey and Site Investigation Manual. See http://www.epa.gov/radiation/marssim/and http://www.ntis.gov/search/product.asp?ABBR=NUREG1575REV1&amp;starDB=GRAHIST for further details.

View Dave Williams’ presentation (pdf - 749kB)

29.9 Workshop on Requirements for Standards and Guidance for Radioactivity Measurements in Site Decommissioning

Julian Dean (NPL) updated the meeting on progress since his survey of the requirements for standards and guidance for radioactivity measurements in site decommissioning. A workshop on the subject had been organised and would be held at NPL on 30 June 2005. The aim of the workshop was to identify the top 2 priorities for standards and/or guidance in bulk monitoring, surface monitoring and radiochemical analysis: all were welcome to attend.

View Julian Dean’s presentation (pdf - 195kB)

29.10 Any Other Business

(i) Contamination Units

John Simpson (RWE Nukem) described their laboratory set-up for the calibration of surface contamination monitors and outlined the various parameters that are used to describe the performance of these monitors. He went on to explain that the actual area of the detector might not be that which is visible, and this could account for some of the variation in comparison results.

View John Simpson’s presentation (pdf - 182kB)

(ii) Dual Phosphor Probes

Peter Burgess (UKAEA) presented the findings of an investigation he and colleagues had conducted into the set-up procedures of dual phosphor probes. The established technique used to set up Thermo Electron’s dual DP6 probe had lead to strange results when applied to a Ludlum dual probe: a low response was obtained for ⁹⁰Sr/⁹⁰Y which did not fall on the plateau, this was found to be due to the pulses falling below the β threshold. Improved results were achieved when the α/β ratio was increased to 22.5:1 rather than 15:1, however it was observed that the β count rose rapidly when exposed to as as the effective β threshold was reduced, and, the γ sensitivity increased. Peter suggested a number of possible causes of these spurious pulses and asked the members for further ideas.

View Peter Burgess’ presentation (pdf - 465kB)

(iii) Joint Industry Projects

Steven Judge (NPL) presented details of the DTI’s Measurement for Innovators Programme. Through this programme funding was available for collaborations with NPL via Joint Industry Projects, secondments and consultancies. Steven proposed that one such Joint Industry Project could be the development of Radio Frequency identity tagging technology for radioactive inventories; he invited members to stay after the main IRMF meeting to attend an afternoon workshop on this topic.

View Steven Judge’s presentation (pdf - 233kB)

29.11 Forthcoming Events

The Chairman presented the following list of forthcoming events (pdf - 255kB).

No other events were announced by the members.

29.12 Next Meeting

The next meeting will be held on Wednesday 9 November 2005 in the Module 16 conference facility. As usual, the meeting will commence at 10.30 am, with coffee served from 10.00 am.

29.13 Workshop on Radio Frequency Identity Tagging of Radioactive Sources

The aim of the workshop was to provide an overview of the latest technology available within RF identity tagging and, where possible, match that to the needs of the radiation community. The following presentations were made and a discussion session followed.

Sellafield’s Challenge: Tracking Radioactive Sources and Other Things (pdf - 57kB)
Steven Judge on behalf of Mike Renouf, British Nuclear Group

HASS and Source Security (pdf - 98kB)
Peter Brember, Environment Agency

Tracking Across the Supply Chain
Janet Townsend and Sonia Ashmore, PA Consulting

Use of RFID for Inventory Control (pdf - 1324kB)
Bob Thomas and Chris Thomas, Avonwood

Before closing the workshop, Steven Judge (NPL) asked that anyone interested in forming a consortium to explore the future possibilities of applying tracking technology to radioactive sources, please make contact with him. steven.judge@npl.co.uk

Clare Lee

IRMF Secretary
Quality of Life Division, NPL

ACTIONS

All Members
Register for Gamma Monitoring Comparison if you wish to participate.

Secretary
Add protocol for Gamma Monitoring Comparison to IRMF website

GPG14 Review Working Group
Clare Lee to organise a meeting of the WG.
Consider effects of uncertainties in pass/fail criteria.

Chairman
Approach the DTI to request funding for a Guide on EPD calibration and to review the Contiguous Portions technique.

John Simpson, Peter Burgess and Tony Richards
Continue dialogue with the NCE2 committee regarding the use of and origin of uncertainties for conversion factors stated in ISO 4037.

Members representing calibration facilities
Send additions and amendments for IRMF Catalogue to the Secretary.

All members
Inform roger.hughes@npl.co.uk of suggestions for presentations on technical topics for the next IRMF meeting before the end of September 2005.

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