Welcome to the 4th meeting of the Airborne Radioactivity Monitoring Users Group

Steven JudgeAndrea Woodman

3000 BC

The "Royal Egyptian Cubit" was decreed to be equal to the length of the forearm … of the Pharaoh or King ruling at that time.

Agenda

• Minutes and matters arising• High Volume Particulate Sampling (Simon

Jerome, NPL)• Reducing avoidable deaths from radon in the UK

(Brian Ahern, Radon Council)• Good Practice Guide (Max Pottinger)• Breakout Groups• AOB• Meeting of GPG Working Group or Lab Tours

Commercial reference sources

• www.isotrak.de• www.analyticsinc.com• www.ipl.isotopeproducts.com/new_ipl_site• www.lea-cerca.com

Air monitor cards

• Isotrak only (as far as known)

• Anodised foils or sealed plastic

• Calibrated to ISO8769

• Customised to match equipment

Cartridges

• Mixed gamma emitters

• Homogeneously mixed with charcoal or zeolite

• Face loaded – sealed plastic foils

Simulated gas standards

• Low density foams, simulating a range of pressures (0.015gcm-3 to 0.20gcm-3)

• Available in many container types

• Isotrak, Analytics, IPL

Filter papers

• Anodized foil type

• Mylar membrane of various superficial densities (0.5, 0.85, 1.7 mgcm-2)

Mylar vs anodized foils

• www.analyticsinc.com/paper1.htm (and references therein)

• Real samples differ from reference materials –self-absorption, backing plates)

• The paper compares mylar coated sources to electroplated

Gas bottle standards

• Pressurised / unpressurised gas bottles

• Glass ampoules

• IPL/CERCA/Isotrak

Measurement of Airborne Radioactivity by the CTBTO

Simon Jerome, NPL

ARMUG, 9th November 2004

Event and date 2

What is the CTBTO?

• The Comprehensive Test Ban Treaty Organisation

• An international organization established by the States Signatories to the Comprehensive Test Ban Treaty on 19th November 1996

• Their main task is the establishment of the 337 facility International Monitoring System and the International Data Centre, and the development of operational manuals, including for on-site inspections.

Event and date 3

Aims of the CTBTO

• To detect, locate and identify nuclear weapons tests down to 1kTequivalent

• The data used to detect, locate and analyse events are processedimmediately, with the first automated products being released within two hours

• The data comprise lists of seismoacoustic events and radionuclides that have been detected by monitoring stations

• Analysts subsequently review these lists in order to prepare quality controlled bulletins

• Implications of getting it wrong are not good

Event and date 4

Monitoring Technologies

• The aim – what, where, when, how, who (but not why)• Seismological monitoring system – size, location and time of underground

tests• Hydroacoustic monitoring detects acoustic waves – size, location and

time of underwater tests• Infrasound network detects very low-frequency sound waves in the

atmosphere – size, location and time of atmospheric tests• Radionuclide network of 80 stations uses air samplers to detect

radioactive particles released from atmospheric explosions and vented from underground or under water explosions (the ‘smoking gun’).

Event and date 5

Network Locations

Event and date 6

Nuclear Weapon

• Initial fission reaction (20 kT - 239Pu)• Fuels second fission reaction (<500 kt 239Pu or 235U)• second fission reaction fuels fusion reaction (yield depends how much fuel

2H/3H in the form Li2H)• finally, fast neutrons induce addition fissions in the weapon containment

(yield depends on rest of weapon – 238U)• Fission products elements from Zinc to Terbium, all volatalised

Event and date 7

Fission Products

Thermal Fission yield s

0.001

1.001

2.001

3.001

4.001

5.001

6.001

7.001

8.001

9.001

65 70 7 5 8 0 85 9 0 9 5 10 0 1 05 1 1 0 1 1 5 1 20 1 25 13 0 13 5 14 0 1 4 5 1 5 0 15 5 1 60 1 6 5 1 7 0

Mass number

% ma

ss yie

ld

Pu -239U-235Pu-241

Event and date 8

Radioactivity remaining

Rad ioactivity after 10 days

1.00E+00

2.00E+15

4.00E+15

6.00E+15

8.00E+15

1.00E+16

1.20E+16

1.40E+16

65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170

Mass number

Activ

ity/B

q

Event and date 9

Radionuclide monitoring

• The radionuclide network of 80 stations uses air samplers to detect radioactive particles released from atmospheric explosions and vented from underground/underwater explosions

• Half of the stations in the radionuclide network also have the capacity to detect noble gases

• The relative abundance of different radionuclides in these samples can distinguish between materials produced by a nuclear reactor and a nuclear explosion

• The associated radionuclide laboratories are used to analyse samples that are suspected of containing radionuclide materials that may have been produced by a nuclear explosion

• The presence of specific radionuclides provides unambiguous evidence of a nuclear explosion

Event and date 10

Performance requirements

• For the network of radionuclide stations:90% probability of detection within 14 days of any event >1 kT

• Distinguish between nuclear explosion and:Radon (allow the sample to decay)Radioactive Xenon used in nuclear medicineEmissions from civil nuclear facilitiesCosmogenic radionuclides

• Based on the detection of 140Ba with a detection limit of 10 µBq/m3

• 1 kT = ~4×1012J = 1.3×1023 fissions = 5 PBq 140Ba• Trying to detect not very much at all of the device!

Event and date 11

Radionuclide monitoring stations

• Air flow: 500 m3/hour• Collection time: 24 hours• Decay time: ≤24 hours• Measurement time: ≥20 hours• Reporting time: ≤72 hours• Reporting frequency: Daily• Collection efficiency: ≥80% for 0.2 µm and ≥60% for 10 µm• Measurement: High resolution γ spectrometry, 88-1836 keV• Sensitivity: εγ >40% leading to 10-30 µBq/m3 for 140Ba• Data availability: ≥95%• Down time: ≤7 days in a row, ≤15 days per year

Event and date 12

Xenon monitoring stations

• Air flow: 0.4 m3/hour• Sample volume: 10 m3

• Collection time: ≤24 hours• Measurement time: ≤24 hours• Reporting time: ≤48 hours• Reporting frequency: Daily• Nuclides monitored: 131mXe, 133Xe, 133mXe and 135Xe• Measurement: β–γ coincidence counting or high resolution γ

spectrometry• Sensitivity: 1 mBq/m3 for 133Xe• Data availability: ≥95%• Down time: ≤7 days in a row, ≤15 days per year

Event and date 13

Supporting measurement

• Network of 16 radionuclide laboratories around the world• Provide more detailed analysis of filters if required

Key Nuclides:95Zr/95Nb – timing99Mo – timing106Ru – fuel132Te/132I – event 140Ba/140La – timing141Ce/144Ce – fuelPure α and β emitting fuel and casing activation products

Event and date 14

CTBTO Country Profile for the UK

Coordinates Location Type Treaty

Code Lat Lon

Eskdalemuir EKA Auxiliary Seismic Station AS104 55.3 -3.2

BIOT/Chagos Archipelago Hydroacoustic Station HA08 -7.3 72.4 Tristan da Cunha Hydroacoustic Station HA09 -37.2 -12.5 Tristan da Cunha Infrasound Station IS49 -37.0 -12.3 Ascension Infrasound Station IS50 -8.0 -14.3 Bermuda Infrasound Station IS51 32.0 -64.5 BIOT/Chagos Archipelago Infrasound Station IS52 -5.0 72.0

AWE Blacknest Chilton Radionuclide Laboratory RL15 TBD TBD

BIOT/Chagos Archipelago Radionuclide Station RN66 -7.0 72.0 St. Helena Radionuclide Station RN67 -16.0 -6.0 Tristan da Cunha Radionuclide Station RN68 -37.0 -12.3 Halley, Antarctica Radionuclide Station RN69 -76.0 -28.0

Event and date 15

Noble gas sampling

• Xenon is adsorbed on charcoal, purified and concentrated• Need to remove water and CO2

Interfere with adsorption of Xenon on charcoal• Radon needs to be removed

Variable concentrations, but much larger than radioactive XenonGas chromatography is used to separate Radon and Xenon

• Variable backgroundNuclear medicine (mainly 133Xe)Nuclear power

Event and date 16

Noble gas measurement

• 131mXe, 133Xe, 133mXe and 135Xe emit γ–rays and similar energy X–ray• Can use γ spectrometry to detect 133Xe (81 keV, 37%), 133mXe (233 keV,

10%) and 135Xe (250 keV, 90%)• 131mXe emits 30 keV X-rays, but no γ–rays; 133Xe, 133mXe and 135Xe also

emit X–rays at this energy• Use β–γ coincidence counting techniques to reduce background for 133Xe

and 135Xe• Use γ–β coincidence counting (gated on 30 keV X–ray) with an energy

resolving β detector to reduce background for 131mXe and 133mXe

Event and date 17

Noble gas interferences

• 131mXe, 133Xe, 133mXe and 135Xe can be present at ground level with activities of up to 100 mBq/m3 from nuclear power and from medical use

• Typically 3-10 mBq/m3 in the industrialiased regions of the northern hemisphere

• (133mXe:133Xe)reactor ~0.1 (133mXe:133Xe)weapon ~10• (135Xe:133Xe) reactor ~0.01 (135Xe:133Xe)weapon ~100

• Medically used 133Xe is practically pure• Activity ratios are more important than activity concentrations in this case:

(131mXe:133Xe:133mXe:135Xe)weapon ~ 1:104:105:107

Event and date 18

Particulate sampling

• Particulate activity is captured on organically based band filters of differing types

• Filter exposed for 24 hours• Allowed to decay for 24 hours

Radon daughter nuclides (mainly 212Pb) decay over this period, reducing interference with 140BaAll other major radon daughters decay to zero in 24 hours

• Measured for 24 hours• Data reported to IDC in Vienna

Event and date 19

Fission Products

Thermal Fission yield s

0.001

1.001

2.001

3.001

4.001

5.001

6.001

7.001

8.001

9.001

65 70 7 5 8 0 85 9 0 9 5 10 0 1 05 1 1 0 1 1 5 1 20 1 25 13 0 13 5 14 0 1 4 5 1 5 0 15 5 1 60 1 6 5 1 7 0

Mass number

% ma

ss yie

ld

Pu -239U-235Pu-241

Event and date 20

Particulate measurement

• Need for calibration standards• Filter standards prepared from solution standards• Detectors calibrated directly (88-1836) keV• Monte Carlo and other modelling techniques not used• Comparison exercises to verify quality of information supplied• CTBTO has very similar quality requirements to ISO 17025

Event and date 21

Comparison exercises

• 2000:22Na, 124Sb, 125Sb, 134Cs, 137Cs, 154Eu, 155Eu, 210PbActivity levels 5 – 250 Bq/filter

• 2001:91Y, 95Zr/95Nb, 99Mo, 99mTc, 103Ru , 106Ru, 132Te/132I, 137Cs, 140Ba/140La, 141Ce, 144Ce, 147NdActivity levels 5–75 Bq/filter

• 2002:91Y, 95Zr/95Nb, 99Mo, 99mTc, 103Ru , 106Ru, 127Sb, 132Te/132I, 137Cs, 140Ba/140La, 141Ce, 147Nd, 154Eu, 155EuActivity levels 0.1–10 Bq/filter

RADON

A VIEW FROM THE OTHER

END OF THE TELESCOPE

A presentation for and on behalf of

The Radon Council

by

Brian H Ahern (Chairman)

There is no getting away from the fact that radiation doses to the public from radon are more than a thousand times greater than those from the whole of the nuclear industry……

There is no surprise in this, except to the wishful thinkers. Itis now time for them to forget their daydreams. Radon is confirmed as the biggest radiation risk to the public by far.

Jon Miles – Excerpt from Radon Dreams - Environmental Radon Newsletter Winter 1998.

Radon is not only responsible for the highest domestic exposures to radiation, it also leads to the largest occupational doses. In some cases the doses are so high that if they arose from an accident in the nuclear industry a high profile prosecution would inevitably follow. Things are less easy when neither the individual concerned, the employer nor the enforcing agency are aware of the situation.

Gerry Kendall - Excerpt from editorial Journal of Radiological Protection.

COMPARATIVE ESTIMATES OF

ATTENDANCE AT MAJOR SPORTING INTERNATIONAL = 25,000+

WITH DEATHS IN THE UK OVER A 10 YEAR PERIOD

FROM RADON = 25,000

FROM PASSIVE SMOKING = 10,000

FROM ACCIDENTAL FIRES IN THE HOME = 3,000

FROM NEW VARIANT CJD = 150

WHY SUCH LITTLE INTEREST?

COULD IT BE THAT BECAUSE RADON IS NATURAL – THERE IS NO ONE TO BLAME?

OR THAT ANYTHING THAT UPSETS THE VALUATION OF A PROPERTY IS BAD

NEWS?

INTRODUCTION TO THE RADON COUNCIL

The Radon Council is a non-profit making self regulatory body.

It is NOT a trade association and was established 13 years ago as a Regulatory Body for the UK radon industry and consumers.

It came about in response to a request from a Parliamentary Select Committee Report on Indoor Environmental Pollution, for just such an organisation to provide regulation, in order to combat the “cowboy elements” that were beginning to enter the radon field.

Its primary objective is to protect the public and not industry.

Despite its origins the Council has rather surprisingly never received any funding from UK governmental or public agencies.

Functions of the Council

Maintain a Code of Good Practice.

Publish “The Radon Manual”.

Provide Training Courses, with examination.

Award of Certificate and CPD points to successful candidates.

Maintain an annual List of Contractors.

Radon Council Services.

Provide a telephone information service.

Provide and maintain a radon website in association with the Universities Radon Network.

www.radonhotline.org

Collaborate with ERRICCA and other International programmes.

www.euradoncouncil.com

Training Course ContentAn intensive whole day course which on completion is

eligible for CPD points.

Radon and Health risks.Detection methods.

Health and Safety Legislation.Radon remediation.

Radon in new-build: Sumps and Barriers.Environmental law. Lecturers’ Forum.

Personal study.Examination.

Main Radon Council Policy

Start to reduce the 2500 avoidable annual deaths in the UK.

Over time test all UK homes.

“To Test is Best”.

Adequate testing and remediation knowledge already in public domain.

Maintain and where necessary raise standards.

The Radon Council is concerned at the avoidable and tragic waste of 2,500 lives each year from radon. Despite numerous initiatives tried over the past decade, at substantial cost to the taxpayer, many people are still unaware of the danger.

The Radon Council is advocating a revision of national policy in order to eradicate this menace and start to reduce these unnecessary annual deaths, by the following means:-

1) Make a minor revision to CON 29 and to include radon in the proposed Home Information Packs (HIPS).

2) All homes both new and old should be required to furnish a valid and recent radon test certificate at the time of conveyancing.

3) Any homes found to have radon levels in excess of the current action level, should be remediated.

Over the past two years the Radon Council has had numerous telephone calls and some correspondence from puzzled consumers asking what a 1% or 3% possibility of there being radon in their home can mean.

The answer is quite frequently whether in ‘bad’ or ‘good’areas it means very little. Like drains, woodworm, dry rot or roof faults,

“To Test is Best”

is the only 100% reliable guide to any individual home and could be a lifesaver into the bargain.

THE LIFE YOU SAVE MIGHT BE YOUR OWN!

WHY SHOULD NEW HOMES BE TESTED?

Although new homes allegedly complying with Building

Regulations will frequently include a “radon membrane”

and some even a “radon sump”, experience shows that

unless these are specified and installed correctly, high

radon levels can still occur.

An estate at Higham Ferrers in east Northampton, where the probability of radon is said to be in the 3% - 10% band was tested.

Results showed that 35% of the properties were over the action level.

Even though they were classified as only requiring secondary protection.

Environmental Management and Health Vol 11. No 4. Year 2000

The following survey conducted by University College

Northampton and Northampton General Hospital

illustrates the problem.

© UCN 2004

A Study of the Efficacy of Radon Proof Membranes

Prof A.Denman, Prof P.Phillips, and Dr R.Crockett

© UCN 2004

Introduction• Since 1992, New Houses in UK Radon Affected Areas must be

built with radon protection. In affected areas, this takes the form of a radon proof membrane as the damp proof course, sometimes with the addition of a sump or additional air bricks.

• Minimum specification is 300 µm polythene sheet, extending over the cavity wall. (BRE Document, BR211)

• UK practise does not require a radon test in such new homes, andthe developers rarely have an effective procedure that informs buyers that the area is radon affected, or that radon preventative measures have been taken.

© UCN 2004

Study Area• The UK Action Level for domestic properties is

200 Bq m-3

Brixworth (NN6 9..) is in Northamptonshire, in an area where 17.7 % of houses have been found to be over the action level.

444 new houses have been built in Brixworth, on a large development with three main builders, since 1992.

© UCN 2004

Measurements• The NRPB Measurement Protocol uses two track etch

detectors placed for three months – one in the bedroom, one in the main living area

• The weighted average of these two measurements is seasonally corrected, and compared to the Action Level

• This methodology was adopted for this study, with an exposure time of 90 ± 2 days.

• 100 Householders in new houses were offered a free radon tests. 63 returned detectors, of which 3 were spoiled, leaving 60 usable results.

© UCN 2004

Study Results•The results have a log-normal distribution

•Showing that sample is not biased•6 houses (10 %) over Action Level•Our recent DEFRA-funded study showed that the equivocal range for 3 month track etch detectors is 112 to 356 Bq m-3

•Above 356 – definitely abnormal•Below 112 – definitely OK•Between 112 and 356 – result should be repeated

•14 houses in equivocal range (23.3 %)•1 (1.7 %) definitely abnormal

© UCN 2004

Analysis

• If the membrane works then all results should be below the Action Level

• It is not possible to have a direct comparison to a control group

• However, NRPB showed that 17.7 % existing houses in the local area (Brixworth and some adjoining villages) were over the Action Level

• Thus the membrane provides inadequate protection in over 50 % of cases.

© UCN 2004

Irish Study• A similar study was conducted by Synnott et al

in two areas in Ireland• Legislation require a BBA Accredited

Membrane • Results were similar

• 11/90 (12 %) in an area where 27 % of existing homes were over Action Level

• 9/44 (20 %) in an area where 45 % over AL

A Survey of the Impact of Amending Building Regulations on RadonConcentrations in Irish Homes, H.Synnott, D.Pollard, P.A.Colgan, and D.Fenton, Proceedings of IRPA11 Congress, 2004

© UCN 2004

Conclusions• The pilot study suggests that radon-proof membranes used

in UK new homes do not always provide adequate radon protection

• The results are similar to an Irish study• The likely cause is damage to the membrane during building

• There is currently no requirement to test new houses in the UK

• This study indicates that it is essential to make radon measurements in new houses, in order to identify those where the membrane provides inadequate protection

RADON TESTING FOR EXISTING HOMES.

The need to test existing (or old) homes is obvious.

The size of the existing housing stock determines that these properties will result in by far the largest number of homes found to be affected by high levels of radon.

It has been suggested that because radon levels can be affected by life-style then in the absence of a radon test certificate the purchaser should move in and test after occupancy. Any buildings found to have high levels could then be remediated and the cost presumably clawed back from the vendor.

WOULD YOU BUY A SECOND HAND MOTOR CAR ON THE SAME BASIS?

Who would wish to buy a second-hand motor car, that might have a latent defect, on the understanding that it could be corrected later if the purchaser’s style of driving caused it tomaterialise.

The Radon Council is totally opposed to this suggestion and advocates the policy of testing all properties at the time of conveyancing. In this way a purchaser will know what they are buying.

TO TEST IS BETTER THAN A GUESS

It is argued by some that meaningful tests cannot be conducted at the time of conveyancing.

This is not the case. Reliable and internationally accepted testing methods for measuring radon already exist, providing the correctinterpretation is placed on the results.

These can be as short as 7 days which is a timescale that does not delay the conveyancing process, or as long as 3 months, a test that can be conducted in many cases well ahead of the sale.

It is important to appreciate that all essential techniques for testing and carrying out adequate radon remediation work are already in the public domain. The Radon Council publishes an annual list of approved contractors, well able to provide services or undertake this work.

Ultimately all properties should be included. This not only means NEW and EXISTING HOMES, but SCHOOLS, HOSPITALS, and WORKPLACES as well.

We operate stricter gas protection regimes against landfill and brownfield gases, which are less dangerous, than we do against a known killer.

LIST OF CONTRACTORS….

The Radon Council publishes an annual list of contractors who have reached an acceptable level of competence and have demonstrated a knowledge of building techniques.

Every entrant has to sign a written contract with this Council and follow a Code of Conduct as well as produce evidence of valid Liability Insurance.

A RECENT COMPLAINT

This is not always the case with contractors who have not received adequate training. The Radon Council has recently received a complaint from a private householder about work carried out by an “approved contractor”.

The example showed a disregard for the IEE Wiring Regulations, undermined the fabric of the building and caused an electrical fault when it rained.

This contractor has not attended a Radon Council training course and does not appear on the Radon Council’s list of contractors.

COMPLAINTS PROCEDURE

As part of its Duty of Care the Radon Council has a complaints procedure.

A Disciplinary Group comprising a chartered chemist, a chartered engineer, a master builder and a legal advisor are available to investigate any complaints received by the Council concerning anyone appearing on our published list.

A few cases have already been considered over the past years and resulted in a successful conclusion for the consumer.

Unfortunately the contractor responsible for the work described in the previous example is not known to the Radon Council and as such we are unable to mediate directly.

The Future

The Radon Council is of the opinion that only when these recommendations have been adopted will a start be made to reduce the unacceptable annual waste of life from radon.

National Good Practice Guide: Airborne Radioactive Particulate in the WorkplaceMax PottingerBNFL Instruments

Page 25665

History to Date

Meeting Feb 2003Scope the document Broad Test Categories

First WG Draft May 2003Review Meeting Sep 2003Second WG Draft May 2004Review Meeting July 2004Abridged Document issued to ARMUG Nov 2004

Page 35665

Revised Content

Abridged document agreedScopeContains summary tables of test required

Removed sectionsSource constructionAppendices: leakage, uncertainties, alarm settingsAddenda may be added later

Final details of testing to complete

Page 45665

Types of Equipment

Airborne Particulate MonitorsNormally some alpha spectrometry

Airborne Particulate samplersDust samplers

Laboratory Counting Equipment

Page 55665

Periodic Tests - Air Samplers

Parameter CheckPump TestFlow rate accuracyLow flow alarm Low differential pressure alarm

Flow Rate Leakage - TBFU

Page 65665

Periodic Tests - Air Monitors

All air sampler testsResponse testBackgroundActivity Alarm Detection Efficiency

Nuclides recommended by manufacturer

Page 75665

TBFU - Air monitors

All Periodic TestsEnergy Response

cover energies encountered in the workplaceCross Response

Check beta rejection by alpha channelGamma compensationOver Range Test

Geiger only monitors

Page 85665

Periodic Tests - Lab Equipment

Parameter checkResponse TestBackgroundActivity alarm testDetection efficiencyEnergy Response - TBFUCross Response - TBFULinearity - TBFU

Page 95665

The Future

Aim for 3rd WG Draft in early 2005

Submission to ARMUG 2005

Additional reference information added in later years