UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Design and realization of a radon chamber

as a secondary standard

A. Compagno, A. Parlato, S. Rizzo, E.Tomarchio

Nuclear Engineering Department, Palermo UniversityViale delle Scienze , Ed. 6, I-90128 Palermo, ITALY

Coimbra (Portugal), June 7, 2010

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

IntroductionRadon gas is an environmental source of contamination, present in human living environments, with problems for human health.

Radon is considered the second leading cause of lung cancer after smoking tobacco. Many homes (or workplaces) contain radon concentrations that are high enough to give their occupants lifetime exposures that could increase their risk of developing lung cancer.

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

IntroductionIt should be stressed that the current actions to mitigate the radon concentration indoors (typically local ventilation) are in contrast with the actions for energy saving in buildings. Hence the need to characterize building materials in terms of an emanation/permeation to radon, selecting those that represent the best barriers for this gas.

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Introduction

Radioactive series

Radon is a radioactive noble gas that comes from the decay of radium in the soil. Radium is also a daughter or progeny nuclide of uranium. Radon is a colorless, odorless, invisible gas that can only be detected through the use of proper equipment and protocols.

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

IntroductionThe air concentration of radon should be limited also in consideration of recent indications regarding a limit of 100 Bq m-3 and an increase of conversion ratio between air concentration and effective dose : C= 300 Bq m-3 correspond to E=10 mSv y-1 ”WHO Handbook on Indoor Radon: A Public Health Perspective”The actual regulation limits are :

National Laws: < 500 Bq/m3 (workplaces);

90/143/Euratom: Old building concentration < 400 Bq/m3

New building < 200 Bq/m3

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

IntroductionTo measure the concentration of radon gas in indoor environments (homes or workplaces) we need tools calibrated with reference to a primary standard. Since it is not easy to have a primary standard, is a useful a secondary standard in which radon concentration is measured by an instrument whose calibration is performed at a primary standard center.

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

IntroductionIn this work we describe the design and the realization of a radon chamber to perform calibration of radon (or radon daughters) detectors.

Other goals is : Research about the influence of the environmental

parameters on the detectors like temperature, pressure, humidity;

Measurement of gas emanation rate from varios materials (soils, building materials, …)

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Characteristics: Volume: Most chambers have volume <1 m3,

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Characteristics: Large volume ;

few chambers have been built with large volumes (one or more rooms) also to calibrate the activated carbon canisters.

Material not permeable to the Radon; Stainless steel is preferable with respect to more

common plexiglas;

Airtightness;

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Characteristics: Uniformity of radon concentration; Also with more instruments to be calibrated insideStability of environmental parameters

To test instruments with different climate conditions in

the range : • temperature range: -10°C +50°C• pressure range : 600 - 1200mbar• humidity range : 5 - 95% Easy decontamination;

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

External source:(short-term calibration)

source: Ra-226 activity (8000 Bq) volume of chamber : 400 l concentration : 20.000 Bq/m3

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

External sourceTo be acquired:

226Ra solid source (activity: 8000 Bq)

furnished by Pylon

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Design specification of the chamber:Air volume : 0.4 m3 Cylinder shape (to avoid uneven distribution of gas inside)stainless steel (i.e. AISI 304)two lids of 60 cm diameter and 8 bolts that secure the lids on the chamber at a sealing O-RINGDimensions: 60 cm in diameter, 129.5 cm in lenght thickness : 4 mm perforated aluminum platforms (supported by small cylindrical supports, to improve gas recirculation) hermetic electrical connectors to transmit data between internal instruments and external computer (USB) Swagelok quick-connects to minimizes spillage and air inclusion.

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Design specification of the chamber

SPECIAL VALVE

SPECIAL CONNECTOR

With this connector it is possible to provide electronic signals inside and

outside the chamber without escape of radon gas

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Design specification of the chamberThe special valves and data transmission allows us to put inside the chamber also the circulating pump. This avoids possible leakage of radon gas because of no-sealing of the pump.

NO

YESchamber

chamber p=pumps=source

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Design specification of the chamber: temperature control

Temperature control is achieved by means of a circulation of water at controlled temperature in a copper pipe of 1 cm outer diameter and 0.1 cm thick wrapped around the chamber with a helical pitch 5 cm. It will all be covered with appropriate insulating material.

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Radon chamber

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Radon chamber(FRONT)

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Radon Chamber(inside)

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Radon chamber (during preliminary tests)

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Radon chamber

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Detectors

AlphaGuard MR1 Rad 7

LR115 E-PERMs CR39

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Circuit of air conditioning: De-humidification

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Circuit of air conditioning : humidification

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Circuit of air conditioning : de-pressurization

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Circuit of air conditioning : pressurization

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Circuit of air conditioning : recycle

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Circuit of air conditioning : washing by pass

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

low pressure over time preliminary tests

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

high pressure over time preliminary tests

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Response variation with pressure: Tests performed at ENEA by one of the authors

and verified with the new chamber

Pressure (mbar)

MR1 Factor

ALPHAGUARD Factor

1000 1 1

975 1 1.024

950 0.978 1.038

890 0.964 1.096

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

In progressAt this moment, further experiments are carried out: Uniformity of radon concentration, by means of an external radon gas source and a circulating circuit with an external pump and E-PERM detectors; Calibration of climate condition regulation apparatus ; Emanation rate of lava rocks coming from different sites;……………..

UNIVERSITA’ DEGLI STUDI DI PALERMO DINDIPARTIMENTO DI INGEGNERIA NUCLEARE

CHERNE 2010 - 6th Workshop on European Collaboration for  Higher Education and Research in Nuclear Engineering and Radiological Protection - 7-9 June 2010 – University of Coimbra – Coimbra, Portugal

Obrigado pela atençãoThank you for attention

Coimbra (Portugal), June 7, 2010