Minutes of the 4th Meeting of the NMS Airborne Radioactivity Monitoring Users' Group
NPL – 9 November 2004
| Attendees: | Steven Judge | NPL (Chairman) | |
| Andrea Woodman | NPL (Secretary) | ||
| Brian Ahern | Radon-One UK Ltd | ||
| Raj Bhanot | BNFL | ||
| Trevor Birkett | John Caunt Scientific | ||
| Derek Brazer | AWE | ||
| Chris Davies | URENCO | ||
| Julian Dean | NPL | ||
| Dave Dear | BNFL | ||
| Mike Dolan | AWE | ||
| James Forde-Johnston | Canberra-Harwell | ||
| Jean-Louis Gouronc | MGP Instruments | ||
| Derek Hammond | NRPB | ||
| Simon Jerome | NPL | ||
| David Locke | Southern Scientific | ||
| Les Martin | BNFL | ||
| Dick Monaghan | Lab Impex Systems | ||
| Trevor Nicholls | Lab Impex Systems | ||
| Tom Nobes | BNFL | ||
| Martin Oliver | Lab Impex Systems | ||
| Hilary Phillips | NPL | ||
| Max Pottinger | BNFL | ||
| Mark Rainbird | AWE | ||
| Chris Reeves | URENCO | ||
| Dale Robinson | BNFL | ||
| David Ryden | Canberra-Harwell | ||
| John Simpson | RWE NUKEM | ||
| Russell Trueman | DRPS Calibration Section | ||
| Eliot Williams | UKAEA | ||
| Apologies: | Alison Dale | NNC | |
| Robert Munro | UKAEA | ||
| Malcolm Wakerley | DEFRA |
1. Chairman’s Welcome, Previous Minutes and Actions Arising
1.1 Steven Judge welcomed members and gave a short presentation by way of an introduction to the meeting. He then asked the members present to introduce themselves.
1.2 Mike Dolan commented that there was a correction to be made to the previous minutes. Action 4.1: ARMUG secretary to change 210Pu to 210Po in section 4.4 of previous minutes.
1.3 Previous Actions
Action A3.1: Andrea Woodman to correct minutes of 2nd meeting. Done.
Action A3.2: Anybody with information regarding self absorption factors to send them to Andrea Woodman. None received to date, action still stands (Action 4.2).
Action A3.3: Andrea Woodman to arrange for speaker on shrouded sampling probes at next meeting. No speaker found for this meeting and group asked to let secretary know if they can suggest an expert for a future meeting (Action 4.3).
Action A3.4: Peter Burgess, David Ryden and John Simpson to set up subgroup on self absorption factors for GPG along with a representative from AWE. No group set up so far, progress of GPG reported on later in meeting.
Action A3.5: Mike Dolan to provide information on 210Po measurements for website. Mike Dolan reported that the measurement data is not yet publicly available but he has asked the author to make the necessary arrangements.
Action A3.6: Steven Judge to contact source manufacturers for a statement on the construction of reference sources for calibrating “card” monitors. The manufacturers were contacted but no response has been given as yet. Steven presented some information he had found about reference sources. There was a lot of interest amongst the group concerning these sources and it was suggested that there be an in-depth discussion at the next meeting. Jean-Louis Gouronc suggested that he might be able to invite a speaker from a French facility which prepares well characterised reference materials.
Action A3.7: Steven Judge to arrange for the issues with reference source construction to be highlighted in next IR newsletter. Done.
Action A3.8: Andrea Woodman to organise register of facilities and e-mail discussion group. Andrea Woodman reported that NPL does not currently have an e-mail discussion facility but if members wish to start a discussion they should e-mail the secretary who will forward it on to the rest of the group. No progress has been made on a register of facilities; this action still stands (Action 4.4).
Action A3.9: Members to suggest expert on filter media for Andrea Woodman to invite to future meeting. David Ryden has volunteered to make a presentation at the next meeting.
Action A3.10: Members wishing to discuss uncertainties, or any other topic at a future meeting should let Andrea Woodman know. No response from group so far, this action still stands (Action 4.5).
Action A3.11: Any member willing to write a FAQ section for website to send it to Andrea Woodman. This subject was discussed later in the meeting.
Action A3.12: Andrea Woodman to arrange for a link to draft standards to go onto the website. Information on draft standards given out in delegate packs and will go on the website with further information from this meeting.
2. Invited talk: “Measurement of Airborne Radioactivity by the CTBTO” – Simon Jerome, NPL
2.1 Simon gave a very informative talk on work carried out by the Comprehensive Test Ban Treaty Organisation whose aim is to detect, locate and identify nuclear weapons tests down to the equivalent of 1kT across the globe.
2.2 Seismological, hydroacoustic and infrasound tests are routinely undertaken along with air sampling to detect radioactive particles released from nuclear explosions in the atmosphere.
2.3 The reactions which take place in a typical nuclear weapon were described and graphs showing the fission yields, and radioactivity expected to remain after 10 days were displayed.
2.4 Air sampling is carried out at 80 stations around the world and the relative abundance of different radionuclides in the samples allows the analysts to assess the origin of the radioactivity. Analysis is done by high resolution g spectrometry and must be made with great accuracy in order to provide unambiguous evidence in the case of nuclear explosions. Other sources of radioactivity which might be detected include nuclear reactors, nuclear medicine, radon and cosmic radiation.
2.5 Half of the monitoring stations also have the capability to detect noble gases, in particular 131mXe, 133Xe, 133mXe and 135Xe. These are measured either by b-g coincidence counting or high resolution g spectrometry.
2.6 Air sampling is carried out daily and the reporting of results to the headquarters in Vienna is done within 72 hours. Comparison exercises are performed between the 16 radionuclide analysis laboratories to verify the quality of measurements made.
2.7 Following the presentation a question was raised as to the reason why the results of tests could not be displayed. Simon explained that it was due to diplomatic procedures rather than problems with the tests.
2.8 A further question concerned any effect that an increasing use of orbiting reactors might have on the tests due to increased cosmic radiation. Simon said that this should not cause problems as the data analysis would still be able to distinguish this radiation from activity due to weapons.
2.9 Simon was also asked by Jean-Louis Gouronc about the testing of the sampling collection efficiency. Simon did not have the information to hand but offered to find out for Jean-Louis.
3. Invited talk: “Radon – A view from the other end of the telescope” – Brian Ahern, Chairman of the Radon Council
3.1 Brian began his talk by describing the dangers of radon which is by far the biggest radiation risk to the public. He estimated that there are 2500 deaths per year due to radon exposure compared with 1000 due to passive smoking. He then went on to describe the apparent lack of concern by the public and suggested that one of the reasons is the potential damage to property valuation.
3.2 Brain explained the purpose of the Radon Council which was set up 13 years ago as a non-profit making self regulatory body for the UK radon industry and consumers. Its aims are to maintain a code of good practice; publish “The Radon Manual”; provide training courses and maintain a list of approved contractors. The Radon Council provide a telephone information service and maintain a website of information www.radonhotline.org.
3.3 Studies have been carried out on new homes which have been fitted with radon-proof membranes and these have been found to provide inadequate protection in many cases hence the need for testing.
3.4 The Radon Council’s policy is to reduce the number of deaths in the UK due to radon and they aim to do this by advising that testing is carried out in all homes in the UK. Any homes found to have radon levels above the current action level would be remediated.
3.5 Comments following the presentation included the opinion that it would be more cost effective to just test houses in risk areas rather than every house. Brian explained that radon can still occur at high levels in unexpected areas and considering that the cost of testing is only around £50 surely it is better to test. Concern was expressed by another member regarding public misconceptions if the risk is highlighted too much.
3.6 Brian was asked about the situation in other countries. He replied that more testing is carried out in Ireland, and the US where it is carried out for legal reasons rather than due to health concerns. Other countries are similar to the UK or have fewer legal requirements.
3.7 Brian was also asked about the measurement protocol which is a four day test. A comment was made that it would be more accurate to test over a few months. It was also remarked that it would be better to encourage the public to test their homes voluntarily rather than to enforce it.
4. Invited talk: “National Good Practice Guide: Airborne Radioactive Particulate in the Workplace” – Max Pottinger, BNFL
4.1 Max updated the group on the progress which has been made on the Good Practice Guide since the previous meeting. He explained that due to the length of time the full document was taking it had been decided to issue an abridged document to the ARMUG which covers the scope and summary table of tests required. This abridged document will go onto the ARMUG website for the time being and be replaced by the full document in 2005 following submission to the ARMUG.
4.2 Max told the group that the GPG working group were meeting after the ARMUG to finalise the details of the tests described in the summary tables. Max explained that sections on source construction, leakage and uncertainties had been removed from the full document for the time being but may be added as addenda at later dates.
4.3 Max then gave an overview of the tests and types of instruments being covered by the Guide.
4.4 Following his presentation Max was asked whether similar documents were being produced in other countries. Max advised that the USA are doing a similar document but that IEC documents do not cover routine testing.
5. Breakout session: Frequently Asked Questions
5.1 Steven Judge described the intention to put more useful information on the ARMUG web page for everyday users of Air Monitoring Equipment, starting with a section of Frequently Asked Questions. Steven split the members into smaller groups and asked them to come up with a list of typical questions which a new RPA might ask, along with the answers.
5.2 Following discussions the groups reported back a list of questions but not necessarily with answers. Steven announced therefore that the secretary would look at the list before the next meeting and contact members of the group for help with the answers (Action 4.6). The list would then be made available on the website.
5.3 The suggestions which were fed back to the group at the meeting were as follows:
1. What is the limit of detection?
2. Where should a safe alarm limit be set to avoid false alarms?
3. What are the effects of long term deposition on filter paper and how should the filters be maintained?
4. How important are the lengths of pipe runs which regards to signal loss and how can a representative sample be obtained?
5. Where is type test data found?
6. What are the different filter types for high volume air samplers? – list of manufacturers
7. What reference sources are available?
8. What are the pros and cons of different detector types?
9. A glossary of terms such as DAC, DACh, etc.
10. What are the radon compensation methods? – simple description in a few lines
11. Why are particular flow rates chosen? - 37 litres per minute is the human breathing rate
12. A general how, what, when, why, where? – eg sample times; positioning of samplers?
13. What are the main uncertainties?
14. How can the best instrument be selected for a particular application?
15. Which standards/specifications must be complied with?
16. Other possible suppliers of information?
5.4 The question was raised as to how the information would be publicised and it was suggested that an article be written for the SRP newsletter and distributed via the SRP mailing list.
6. Any Other Business
6.1 The next meeting is likely to be held in November 2005 and members will be informed as soon as the date has been set.
6.2 Steven Judge informed the group that as Andrea Woodman is leaving NPL in December, the new secretary for the group will be Julian Dean. Any enquiries should therefore be made to Julian via e-mail julian.dean@npl.co.uk or by telephone on 020 8943 6278.
7. Actions arising from this meeting
A4.1 Secretary to change 210Pu to 210Po in section 4.4 of previous minutes
A4.2 Anybody with information regarding self absorption factors to send them to Julian Dean.
A4.3 Any suggestions for a speaker on shrouded sampling probes to be given to Julian Dean.
A4.4 Julian Dean to set up a register of facilities.
A4.5 Members wishing to discuss uncertainties, or any other topic at a future meeting should contact Julian Dean.
A4.6 Secretary to complete list of frequently asked questions and answers with help from the rest of the group.
Andrea Woodman
Secretary, ARMUG
16th November 2004