Thursday 29^th November 2007
National Physical Laboratory

Present:

Chairman:		Pete Burgess		National Physical Laboratory
Secretary:		Lynsey Keightley		National Physical Laboratory
		Duncan Aston		High Technology Sources
		Bhaswar Baral		Centronic Ltd
		Jen Barnes		AMEC
		John Bennett		DSTL
		Reg Bosley		RWE Nukem
		Derek Brazer		AWE
		John Caunt		John Caunt Scientific
		Oliver Caunt		John Caunt Scientific
		Jeremy Caunt		John Caunt Scientific
		Ray Chegwin		NPL
		Ludovic Chevallereau		Serco Assurance
		Rob Corby		Magnox Electric
		Bill Croydon		Radiation Watch Ltd
		Tim Daniels		HPA
		Paul Deacon-Smith		Medical Physics Directorate, St Thomas’s Hospital
		Julian Dean		NPL
		Denise Delahunty		Regional Rad. Physics & Protection Service
		Geoff Druce		AWE
		Alan DuSautoy		NPL
		Jonathon Fawcett		ThermoFisher Scientific
		David Gallacher		Medical Physics Directorate, St Thomas’s Hospital
		Andy Galpin		Nukem
		Paola Hayes		HMS Sultan
		Chris Hill		Thermo Fisher Scientific
		Michael Hodgson		Thermo Fisher Scientific
		Ed Holden		Berthold Technologies (UK) Ltd
		Richard Jenkins		BAE Systems Ltd
		Alfred Klett		Berthold Technologies (UK) Ltd
		John Lillington		Serco
		Shaun Marriott		BAE Systems Ltd
		Richard Marsh		Southampton University
		Duncan McClure		HPA
		Jan McClure		HPA
		Ray McConnell		BIL Solutions
		Kyle Miller		Defence Equipment & Support
		Roy Mooney		NI Medical Physics Agency
		Robert Newiss		Nukem
		Mairin O'Colmain		Radiological Protection Institute of Ireland
		Nigel Pearce		UKAS
		Tony Richards		Consultant
		Joanne Shaw		HPA
		Jon Silvie		BAE Systems Ltd
		Keith Simmons		Defence Equipment & Support
		John Simpson		Nukem
		Karen Southall		HPA
		Sinclair Tait		Nukem
		Rick Tanner		HPA
		Graeme Taylor		NPL
		Simon Threadingham		DSTL
		Jonathon Wardle		AWE
		Graham Whish		Addenbrooke's Hospital
		David Williams		Magnox Hinkley A
		Michael Woods		IRMC

On behalf of NPL, Pete Burgess welcomed delegates to the 34th meeting of the IRMF.

34.1  Diagnostic X-ray Comparison

Denise Delahunty (RRPPS) informed the members that there has been little progress with the comparison since the last meeting. Lynsey Keightley (NPL) will speak to Martin Kelly (NPL) to organise for the participant’s results to be forwarded to Denise as soon as possible.

An update on the results will be available at the next meeting.

34.2  Gamma Monitoring Comparison

Duncan McClure (HPA) gave an overview of the comparison exercise and reported very little progress since the previous meeting. There had been problems with the SmartIon at low dose rates and measurements need to be repeated.

Duncan asked the group if they wished to abandon the comparison. It was decided to carry on with the exercise as planned.

John Wardle added that AWE had never received an instrument but wish to take part.

Action: Duncan McClure will arrange for the instrument to be sent to Jon Wardle (AWE) and also BIL.

All results are to be sent to Duncan and Martin Kelly (NPL) before Christmas and will be provisionally reported during the May 2008 meeting.

View Duncan McClure's presentation ( PDF 112 KB)

34.3  Neutron Monitoring Comparison

Graeme Taylor (NPL) informed the members that the comparison has not really progressed and has now effectively started again. The instruments are currently being circulated to labs and there should hopefully be more to report at the November 2008 IRMF meeting.

34.4  Surface Monitoring Comparison

Pete Burgess (NPL) reminded members that the previous surface contamination comparison exercises (2000 and 2004) had both produced poor results. Both Pete and Reg Bosley (RWE Nukem) had investigated some possible discrepancies and Pete presented a list of possible causes.

The next step will be to measure the emission rate of some of the sources and compare the value with the instrument indication and nominal emission rate. NPL will measure the emission rate of sources free of charge. For more information contact Pete Burgess.

View Pete Burgess's presentation ( PDF 180 KB)

View an autoradiograph of two large area beta reference sources ( PDF 714 KB)

34.5  UKAS Labs Comparison

Mike Woods (IRMC) informed the members of a recent surface contamination comparison exercise between UKAS laboratories.  The comparison started in July 2007 and seven UKAS accredited organisations took part. Final results where received just days before the IRMF meeting and will be collated by February 2008.

Provisionally there is good agreement between UKAS laboratories and they were all compliant with type test data. However, the exercise has also questioned the reliability of type test data.

View Mike Woods' presentation ( PDF 153 KB)

34.6  An Update from the EPD Working Party

There has been an increase in the number of users of EPDs from outside the nuclear industry over recent years and these users are less familiar with the characteristics of EPDs than those working in the field. A working party has been put in place to produce a Good Practice Guide giving guidance to those who are less informed of instrument capability.

Jan McClure (HPA) gave an overview of the EPD working party and the testing required for EPDs.

34.7  Review of GPG14

Pete Burgess gave a brief reminder that GPG14 was under revision. A draft copy will be circulated by end of December 2007. For more information contact Pete Burgess.

34.8  Uncertainties on surface contamination monitor calibrations

Mike Woods (IRMC) gave an interesting presentation on the assessment of uncertainties in radiological calibration and testing. In many cases, uncertainties are significantly over estimated, when in fact the overall uncertainties for calibration factors could be of the order of 2 – 3 % (k=1). Mike added that GPG49 should be used as a guide on how to manipulate your readings, and not to provide recommended values.

View Mike Woods' presentation ( PDF 56 KB)

34.9  ISO TC 85 WG17: Update on draft standards

Tony Richards (consultant) provided members with an update on the various ISO standards currently under revision by WG17.

ISO18589 (Radioactivity in the environment): Part 1 has recently been published. Parts 2 and 3 are to be published early 2008. Further sections are currently still being reviewed.

ISO11929 (Determination of the characteristic limits for ionising radiation- fundamentals and application): The first stage document should be completed by end of December 2007, with a discussion document to be produced early 2008.

ISO7503 (Measurement of radioactivity – Evaluation of surface contamination): After various drafts being produced and circulated, the feedback from many organisations pointed out some issues with the approach suggested. The working group are currently working on a revised approach. Tony will update members of IRMF on any progress.

Tony would like to give members of IRMF the opportunity to view the list of draft ISO standards. For more information contact Tony Richards.*

View Tony Richards' presentation ( PDF 188 KB)

ISO8769 (Reference sources for the calibration of surface contamination monitors): Mike Woods' (IRMC) recent involvement in uncertainties and the UKAS laboratory comparison has made it clear that ISO 8769 should be revised. A draft has been produced and is currently being circulated around national committies for comment. Any comments on this revision should be directed to the BSI NCE/2. For more information contact Mike Woods.*

View Mike Woods' presentation ( PDF 58 KB)

*To comply with the Data Protection Act, we cannot publish external speaker contact details, so please contact Lawrence Jones at NPL, as necessary.

34.10  Variations in performance of dual phosphor contamination probes

Sinclair Tait (RWE Nukem) gave an interesting presentation on the problems that occured when UKAEA decided to use Ludlum 43-93 dual phosphor contamination probes as a replacement for the DP6 probes.

RWE Nukem are responsible for the testing and maintenance of the probes and they encountered various problems when using a set up procedure produced by Pete Burgess (when working with UKAEA) and Reg Bosley (RWE Nukem). This had worked well for the first batch but not for the second batch. Sinclair looked into the issues and the information has now been passed on to Ludlum who are investigating further. 

View Sinclair Tait’s presentation ( PDF 570 KB)

34.11  Estimating the mean indication from a rate meter at low count-rates

Pete Burgess showed the members two short video clips of a rate meter operating at different count-rates. Delegates where asked to make a note of the readings and specify the method used. The mean results for the different techniques agreed well.

Low count rate results

Technique	Participants	Mean	Standard deviation	Maximum Value (s-1)	Minimum Value (s-1)	Range compared to mean (%)
Eye average	27	11.93	0.47	13	11	±9
Average of max and min	8	12.03	0.28	12.5	11.5	±4
Average of several readings	4	12.05	0.41	12.6	11.6	+ 5, - 4
Unspecified	9	11.83	0.61	13	11	9

Overall mean = 11.94
Full range = 11 to 13, ± 9 % of mean

High count rate results

Technique	Participants	Mean	Standard deviation	Maximum Value (s-1)	Minimum Value (s-1)	Range compared to mean (%)
Eye average	27	137.70	4	145	130	- 6, + 5
Average of max and min	8	137.70	2.71	142	135	- 2, + 3
Average of several readings	4	134.05	1.60	1335.6	132	- 2, + 1
Unspecified	9	139.10	4.70	145	130	- 7,  + 4

Overall mean = 137.7
Full range = 130 to 145, - 6 to + 5 % of mean

At low count rates, all results were within 9 % of the mean, even though the recorded sequence was quite short.
At high count rates, all results were within - 6 to + 5 % of the mean.
Mean results for the different techniques agreed well.
There was probably little to choose between the methods. The eye average at low count rates had the widest spread but also by far the largest number of participants.

34.12  Soft-waste Drum Comparison and Workshop

Julian Dean (NPL) informed members of a soft-waste drum comparison recently organised by NPL, as a result of the NPL Decommissioning Workshop 2005. A large volume (200 l) drum was prepared using partially filled bottles of spiked ion exchange resin and was circulated to 18 UK labs for measurement. The final report on the comparison was issued in November 2007 (NPL Report IR2).

A further workshop was held in September 2007 and the results of the comparison discussed. It was decided that a second comparison be organised by NPL in 2008 containing a 'hotspot' of activity.

Julian added that delegates of the workshop had also expressed an interest in a Monte Carlo modelling user forum. Alan DuSautoy (NPL) added that there would be a MCNEG annual meeting at Sellafield, Risley in March 2008. Details of the meeting can be found here: http://www.mcneg.org.uk/mcneg08.html

View Julian Dean's presentation ( PDF 258 KB)

34.13  ICRP Update

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. The final draft was approved in March 2007 by the ICRP main Commission and finally published in November as ICRP 103.

Rick informed members that there would be effectively no change to operational quantities; however, there would be changes to effective dose and new E conversion coefficients for all radiation types. The new conversion coefficients are currently being calculated by DOCAL and should be agreed in the near future.

View Rick Tanner's presentation ( PDF 411 KB)

34.14  RPA 2000

Pete Burgess (NPL) gave members an update on the QP accreditation process. The RPA2000 committee had previously contacted NPL to establish if there was any interest in formal QP recognition. This had existed in the past but had been abandoned during the RPA accreditation.

A draft set of competencies are currently being debated by the RPA2000 group. The general consensus is that smaller organisations are in favour of formal recognition but larger organisations are against the idea.

View Pete Burgess's presentation ( PDF 129 KB)

34.15  Development of a field portable tritium instrument

Richard Marsh (Southampton University) is currently looking into developing a field portable tritium instrument as part of his PhD. He gave a presentation on the range of detectors used for tritium monitoring and the advantages and disadvantages of using them in a portable instrument.

View Richard Marsh's presentation ( PDF 737 KB)

34.16  Recovery from a major problem with a Mainance Calibrator

Jon Fawcett of ThermoFisher Scientific gave an interesting presentation on a problem they had when the source carousel was jammed on their Mainance calibrator as a result of a flood in July 2007. Repair work is being carried out and the calibrator is currently of service. He stressed the importance of planned preventative maintenance, particularly for older calibrators that may be prone to a similar failure.

Jon thanked HPA and NPL for the use of their calibration facilities in recent months and also staff from AWE and UKAEA for their help in finding the possible causes of the equipment failure.

34.17  Any other business

The next meeting will be held on Wednesday, 28th May 2008.

Lynsey Keightley

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