1997 Intemational Symposium onEnvironmental Radiation
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1997 Intemational Symposium on
　　Environmental Radiation
October 20， 1997

Green Plaza Hotel
　Tsuruga， Japan

1　Welcome Address
　Y.Yamazaki(The Atomic Energy Society of Japan)

2　lnvited Talks
　Chairperson M.Shimo(NIRS)
　　●The History of Environlnenta1 Monitoring in Taiwan
　　　Yu-Min Lin(Taiwan Radiation Monitoring Center)
　　●The Present State of Environlnenta1 Monitoring in China
　　　Wang Hengde(China lnstitute for Radiation Protection)
　　●Review on lndoor/Outdoor Radon Measurements in Korea
　　　Yoon Shin Kim(Hanyang university)

3　EnvironmentaI Radiation　l
　Chairperson K.0da(Kobe univ. of Mercentile Marine)
　●Present Situation of EnvironmentaI Radiation Monitoring in Taiwan
　　and Japan
　　N.Fujinami(KPIHES)
●Keeping a Radiation Diary
　S.Minato and H.Matsuda(GIRI,Nagoya)
●Natura1 Radiation and Radiation-lnduced Luminescence
　T.Hashimoto(Niigata univ.)

4　Environmental Radiation II
　Chairperson H.Yamanishi(NIRS)
　　●An Anajysis of Combined Standard uncertainties in Radioadive En-
　　　vironment Measurement
　　　T.Kuan(INER)
　　●Simple Measurenlent of Cosmic Ray EXPosurein lnternationa1 Air-
　　　nights
　　　K.Fujitaka(NIRS)
　　●Probability Distributionsof the Energy Deposited in a Plastic Scin-
　　　tillator by Cosmic-Ray Electrons in the Lower AtmosPhere
　　　l.Urabe，H.Sagawa(Fukuyama univ.)

5　Environmentaｌ Radioactivity l
　Chairperson T.lida(Nagoya univ.)
　　●Challenge to Detedion Limit of EnvironmentaI Radioactivity
　　　K.Komura(Kanazawa univ.)
　　●Radioactive Disequilibrium of uranium and Thorium Series Nudides
　　　in River VVaters from Ta-Tun volcano Group Area in Taiwan
　　　T.Chu，JAvang*and H.Huang (NationaI Tsing Hua univ. ＊RMC)
　　●Equilibrium Factor and unattached Fraction of Radon Progeny Mea-
　　　surenlnet at Kaohsiung， Taiwan
　　　C.Chen， C.Liu and Y.Lin(RMC)
　　●Some Problems on Determining Equilibrium Factor， Unattached Frac-
　　　tion and Ssize Distribution of Radon Progeny
　　　K.Yamazaki(KURRI)

6　Environmentaｌ Radioactivity II
　ChairpersonY.Sakuma(NIFS)
　　●Competitive Sorptions between various Cations and Cesuim or Nat-
　　　ura1 Mordenite
　　　T.Liang，J.Y.Tsai and Q,Yeh (TPC)
　　●Natura1 Radionuclide in both the Costal and the Land Soi1
　　　H.Hayakawa(Fukui Pref.)
　　●Long-Term lnvestigation of the Tritium Transport in the Saturated
　　　Aquifer
　　　T.Wang and J,Chiu (INER)
　　●Long-Lived ArtinciaI Radionudides in Environlnent
　　　Yamamoto(Kanazawa univ.)

7　Closing Remarks
　K.lshidoshiro(The Kansai Atomic Conference)

8　　Secretariat
Y.0gawa(Kinki univ.)and T.Chu(Nationa1 Tsing Hua univ.)

Present Situation of Environmentaｌ　 Radiation
　　　　Monitoring in Taiwan and Jaｐan

　　　　　　　　　　Naoto Fujinami
　　Kyoto Prefedural lnstitute of Hygienic and
　　　　　　　　Environmenta1 Sciences

395 Murakami-do， Fushimi-ku， Kyoto 612， Japan
　The present situation regarding environnlental radiation monitoring obserbed by the author at the Taiwan Radiation Monitoring Center in June 1997 isd iscussed. THese observations are then compared with the currentsituation in Japan.
　The Taiwan situation outline is as follows:　1)lt has become dimcult to deepen the Publics comprerension concerning the results of radiation monitoring， 2)Cobalt-60 has been detected in environmental samples such as soil and indicator Plant around nuclear powerstations.3)lt is desirable to promote coll aborative studies betxveen Taiwan and Japan in this neld.
　Procedures arereviewed with which each prefectural radiation monitoring authority in JaPanassesses and evaluates public exposureto radiationand radioactive materials in theenvironrnent， resulting from the operationof nudear facilities.
　While there are several small differencesin the Procefure among theauthorities， the Primary obμctive if environnlental monitoring remainsconstant，that is every procefure is satisfactory toensurethat the public exposureto radiation is well below the limit and、 thus， to Protect Public heakth and safety in the vicinity of nudear facilities，

Keeping a Radiation Diary

　　　　　　　S.Minato and H.Matsuda
Governments lndustrial Research lnstitute， Nagoya
　lt is wll-known that radiationexposuredose rate levels vary with locations.However， even for the same locations， exposure of a person should change with individual life style. ln this paper， l show six people'sone week datatakenon anhourly basis. The comparison arnong those data reveal how big the exposure is difrerent with each other. This suggests that outdoor radiation surveys might not be enough to evaluate populationexposure.
Natural Radiation and Radiation-lnduced
　　　　　　　　　Luminescence
　　　　　　　　Tetsuo Hashimoto
Department of chemistry, Faculty of Sdence、
　　　　　　　　Niigata university
　lkarashi-ninocho，Niigata、950-21， Japan
　Since some parts of natural radiations could beaccurnulated as radiation defects in a variety of natural minerals， the luminescence phenon!ena accompanied by stimulation ofmineralscould be useful as a natural radiationdosemeter.
　ln the author's laboratoryjt has been revealed from thermoluminescence colour images (TLCI)of natural quartz grains that thereare renlarkabley diflerent colour images， which are readily distinguishable into red (RTL) and/or blue TL (BTL)emitting grainsanlong the geoloがcally difrerent quartz origins; RTL grainsare lnainly assignable to high quartzes (on the formation)from volcanic origin and origina1 BTLonesto low quartzes from plutonicorigin.0n the basis of dose resPonse curves， the RTL dating using a coarsequartz indusion method and naturallyaccurnulated doseshas been connrmed to be useful for the reliable dating of tephra layers in comparison with the BTL-measurements.
　Subsequently，byrneansof simply direct contact of the irradiated rock slices with a colour negative nlmjnvolving crystal quartz slice， some 2dimensional cororful luminescencepatterns are also obtained as AGCI (after glow)，PIP(photon-induced phosphorescence)，and OSL (Optically stimulated luminescence)as well as the TLCI. Particularly，an oPtically stimulated luminescence (OSL)image was nrst obser゛ed asa nlonochromatic expression of digital data from every pixel under continuous Pulse laser stimulation.
　From the TL,colourchange studies of Z,cut slice from a rock crystaljt was connrmed that origina1 BTL intensities are inversely proPortional to the Al contents and -OH concentrations as a nlajor impurity in quartzes:this changeability of TL-colour towards RTL after thermal annealing treatment was intimately correlated with the square of A1-concentrations， suggesting RTL-center formation at highly distorted sites due to two A1-substitution atoms in Si-O rings.
　　An Analysis of Combined Standard
uncertainties in Radioadive､Environmentaｌ　Measurement

　　　　　　　　　　　Te-Chi Kuan
　　　lnstitute of Nuclear Energy Research，
1000，Xvenhuah Rd.，Chiaan village， Lungran，
　　　　　　　　　Taiwan 325， R.0.C
　The reliability and uncertainty assessnlent in chemical determination with instruments，technique and method is supposed to be an indisPensable technique in the measurelnent field. The accurate and high quality data acquisitions intended forusein radiological risk assessnlents and environrnental rneasurernent quality assurances will require the incorporation ofuncertainty analysis. This report introducesthe upcoming measurenlentuncertainty analysis anticipated to be practicahn publicrecognitionjnduding a variety analytical procedures(e･g， additionand recovery factor of tracer，emciency of detector，quantity of sample， and analyte faetor)and combined standard uncertainty， and developes a systematic Process to compute the CSU from the constituent components of an analytical procedure.XVe also discuss the contribution of the various sources of uncertainty to overaII CSU value.The equations for CSU computationareapplied to the radioactive environmental samples with the Quattro Pro spreadsheet.
Simple Measurenlents of Cosmic Ray Exposure
　　　　　　in lntenational Airflights
　　　　　　　　Kazunobu Fujtaka

National lnstitute of RadiologicaI Sciences
1　　lntroduction
　Cosmic ray exposure in airnights is considerably large， which sometimes exceeds limits for radiation workers in cases of extraordinary large solar fares.UNSCEAR， ICRP， and NCRP pay large attention to this， and many computer calculations using the CARI-code(1)have been done in USA and European countries to estimate the dose.However， such calculations are valid only for mean geomagnetic latitudes ゛ithout geomagnetic anormary and for stable solar activities without sudden Proton events. As actual dose depends largey on individual cases， we need to collect many measured data prior to considering regulation. To facilitate this， numbers of easy andreasonably accurate measurements are wanted. This report presents examples of dose rate measurenlents by simple pocket dosemeters in international nights.

2　Measurements
　usually,on-board measurements of cosmic ray dose in commercial airlines are done only for ionizing comPonents･ However，neutron dose with become significant at high altitude at which most intercontinentj jets ny， ln view of this， neutron dose was also measured here， though limited insouth american nights and only ionizing components were measured in other nights.
　Real time measurenlents of dose rates are preferable、 and we had done these in early 1990゛s by heavy instruments with specia1 Permission of airline company， However it is not always possible. ln view of this， we have done simple measurernents by the use of pocket dosimeters in three intercontinent nights and many short nights in Brazil (geomagneticanorrnary)in 1997.Two types of pocket dosimeters were usedj.e，one for ionizing com-ponents and another fk)r neutrons. lndicated valuesxvereread frequently (every several minutes to every an hour)，and dose rateswerederived from each pair of adjascent doses.The read valueswere converted to dosesusing a conversion factor of okano(2)which was basedon experimentj nights in 1980's.

3　Results
　Raw data of neutron dose rates (as indicated)are larger than the ionizillg components，However it will be overestimation as a neutron dosemeter renects signals from protons which are invol゛ed in impinging nux.　lf the neutron dose is estimated with okano゛s suggestion (40ionizing components゛)instead，cosmic ray dose inoneintercontinental airnight (return triP)approximates one month sum of the whole natural radiation dose which a member of the publicreceives on the ground.

References
　(1)XV.Friedberg, F.E.Duke,L.Snyder,D.N.Faulkner,K.0゛Brien,D.E.Parker，M.A.Shea，and D.F.Smart:" Computer program CARI-2≒Nationa1 Technical lnformation Service， VA(1994).
　(2)M.0kano,K.Fujitaka and K.lzumo: Measurements of cosmic-ray doses in commercial airhne cabins， Proceedings of IRPA-9， 1996 1nternational Congress on Radiation Protection， vienna, vo1.2，262-264(1996).
Probability Distributionsof the Energy
　Deposited in a Plastic Scintillator by
　Cosmic-Ray Electrons in the Lower
　　　　　　AtmosPhere

　　　　ltsumasa URABE and Hiroyuki SAGAWA
　　　Faculty of Engineering， Fukuyama university
Gakuen-cho 1， Fukuyama-shi，Hiroshima 729-02， JAPAN
　Flux densities of cosmic-ray charged partides have been measured by using an organic scintillation sPedrometer on theassurnption that the energy loss perunit path length in the crystal is constant for both muons and electrons. Butjt is quite possible that these two kinds of Partides may show diflerent characteristics of energy depositions in the organic scintillator. ln this paper， probability distributionsof the energy deposited by cosmic-ray electrons in the organic scintillator were calculated to know the difference between the pulse-height spectra bynluons and electrons， and the distortion of the spectra caused by surroundings of the organic detedor were also calculated for discussion of the diflerencesbetween the pulse-height spectra obtained experimentally by a single detectorcounting method and a coincidence counting method.
　The pulse-height distributions by cosmic-ray electrons in the natural environnlentivere calculated using the energy spectrum of cosmic-ray eledrons by 0.C.AIlkofer.lt became evident that the maximum absorbed energy could be observed up to almost 100 Mev and the pulse-height distribution by the single detectorcounting system is very much difrerent from that by　the coincidence counting system in the energy region below 20 Mev. Furthermore，it also　becanledear that the pulse-height distribution by cosmic　ray electrons seemed to be greatly different from that by muonsbecause the　latter spectrum is　expeded to increaselinearly itscounting rate with absorbed energy to the maximumenergy Emax. Sojt may be concluded that　the dosimetry of cosmic-ray electrons will be performed separately from the　muon dosimetry in the future.
Challenge to Detection Limit of Environmental
　Radioadivity

　　　　　　　　　　　　Kazuhisa Komura

Low Leve1 Radioadivity Laboratory, Kanazaxvauniversity
　　　　Wake，Tatsunokuchi，lshikawa 923-12， Japan
　An underground laboratory (Ogoya Lab)forthemeasurernent oflow-level radionudides was constructed in the tunnel of the former ogoya Copper Mine,located about 40km SSXv ofKanazaxva.Thesoilcoverage ofthe tunnel is 135 m which is equivalent to a water depth of 270 m. Twocountingrooms (5.4×2.0m)were built at about 290 m from the entrance of the tunnel， Detectors set in ogoya Lab are low-backgroundcoaxial Ge detector (relative emciency : 93.5 Background level of these detectors ｀゛as reduced by massive shield (20 cm old iron and 5 cm low background lead bricks. Further reduction of background was attained by minimizing the volume of free-airaround detectors and by introducing N2 gas from liquid nitrogen dewar.Background count rates of these detectors are 1.26 cpm (100 − 2800kev)forcoaxiaI Ge， 0.79 cpm for Ge-LEPS (20 − 1600 kev)and 0.02 cpm for Si detector (20−2000kev).Though background Peaks of naturj U， and Th- series nuclides， K-40 and artincia1 Cs-137 and Co-60 are still observed in the spectrum， however，count rates of these peaks are orderof 0.00n
cpm[n=1to6]and negligible low in the ordinary measurernents.The minimum detectable activities by assuming 10,000min ofcounting time for 50 g samPle are about 2 ppb for U and 3 ppb for Th and 1.1 mBq for Cs-137. The samples measured by Ge are air-borne dust， soils， lake sediments， TLD
and glass dosimter， A-bomb exposed samples， fossil bones， meteorites fe11in 1995 and 1996 etc. Si detector is used for the measurement of cosmic-ray induced P-32 and P-33 in marine environment.
Radioactive Disequilibrium of Uranium and
Thorium Series Nuclides in River xvaters from
　　Ta-Tun volcano Group Area in Taiwan

　　　Tieh-Chi Chu， Jeng-Jong VVang*and Hui-Ling Huang
Department of Nuclear Science， Nationa1 Tsing Hua univercity
　　　　　　　　　　　Hsinchu 300， Taiwan，R.0.C.
　　　　　　　　　　Radiation Monitoring Center，
　　　　　　　　Kaohsiung Hsien， Taiwan 833， R.0.C.
Alpha spectrometry and liquid scintillation counting were used in this study to analyze the radioactivities of naturally occurring radionuclides 238U,234U,232Th,23oT11,228Th，and 226Ra in the river waters from Ta-Tunvolcanog roup area in North Taiwan. The respectiveconcentration range of 238U,234U,232Th,23oT/1,228Th，and 226Rα was 0.80−48,1.2 − 51,0.05−44,0.09 − 39,0.19 − 342， and 3.0 − 22.5mBq￣1，and the 234U/238U and 238Th/232Th activity ratio sweregreater than 1， indicationg radioadive disequilibrium in the waters. The high 228T/1/232rRa activity ratios showed that besides the recoil efrect、 the enrichment of 228Ra to 232Th in the waters was another possible factor causing theexcess of 228Th.The concentrations of uranium and thorium in the river waters changed with the ph of the water. The U/Th concentration ration w・about 1; in the acidic（ph＜5）samples; whereas that was much higher than l in the neutral （ph z 7）samples.
Equilibrium Factor and unattached Fradion of
　Radon Progeny Measurernent at Ka.ohsiung, Taiwan

　Ching-Jiang Chen， Chi-Chang Liu and Yu-Ming Lin
　　　　　　Radiation Monitoring Center， AEC

823， Cherng Ching Road， Kaohsiung，Taiwan 833， ROC

　To reasonably estimate citizen dose from radon， equilibruim fador， Fp，and unattached fraction， fP，of radon progeny are important parameters.
Most FP measuremnets ゛ere based on a set of Lucas cell and working level monitor，Unattached fraction is measured by SARAD GmbH EQF3020. A house was chosen to measure the Fp and fp in difrerent rooms.Another 14 dwellings were measured in bedroom. Two hospotalswerealso chosen for measurernnetof FP in working places located at basement. The average Fp for dwellings is about 0.5 and averaged unattached fradion is about 0.03.Both of them varied between one dwelling to another dlle to different locationand living style. The radon levelsarehigher then that of dwellings while Fp in hospitals are very low， about 0.06， because of the usage of dehumidiner which is common in bassemnet at Taiwan for reducing high humidity induced fungi problem
Some Problems on Determining Equilibrium
　　Factor， Unattached Fradion and Size
　　　　Distribution of Radon Progeny

　　　　　　　　　　　　Keizo Yamasaki
　　　Research Reador lnstitute， Kyoto university
Noda,Kumatori-cho，Sennan-gun，0saka 590-04， Japan
Equilibrium fador， unattached fraction and activity weighted size distribution of radon progeny are the important physical factors to estimate the population dose by the inhalation of radon Progeny. A large number of researchersnleasurethese Paramaters mjnly using their own methods.
ln spite of their careful treatments and calibrations， the accuracy of the data is unknown in many cases owing to lack of standardized procedures to measure these parameters.
　We point out some problems such as the collction perfornlanceofsampling filter and wire screen， the energy dependence of counting efficiency，the alpha recoil and overlap at energy spectrum analysisけhe accuracy of size distributions measured by screen battery methos and cascade impadors，etc.
　This report describessonletechnical methods to treat of these problems.

　　Competitive Sorptions between various
Cations and Cesium or Strontium on Natural Mordenite

Tien-jui Liang， JosePh Yue-cheung Tsai， and xvei-wen Yeh
　　　Radiation Laboratory， Taiwan Power ComPany
　P.0.Box 7， Shihmen，TaiPei、Taiwan，RePublic of China
Natural 　Radionuclides in both the Coast Soil
　　　　　　　and the Land Soil

　　　H.Hayakawa，S.lgarashi， H.Matsuura
Fukui Pref. EnvironmentaI Radiation Research
　　　　　　and Monotoring Center
With the low level exposure rate in the coast as a start， we studied the natural radionudide concentrations of both the land soil and the coast sand in the area having some kinds of geological conditions. The concentrationsof the U-series nudides and Th-series nuclideswerehigher in the soil than these in the sand not depending on the geological conditions.0n the other hand，there was no change in the 40K concentrations of the soil and the sand in the granite region. Butjn the sedimentary rock region， the 40K concentrations of the sand were lower than that of the soil. The 40K concentaration of the sand tends to increase with decrease in the partide size. This was a opposite tendency in comparison with the tendency 拓und in the land soil，　The concentrations of the U-series nuclides and Th-series nuclides in the coast soil have no dependency on the partide size except in the smallest fraction of the size. ln the last fraction， the concentrations sharPly increased. We separated the minerals from the soil by magnet. The magnetic minerals have ahigh concentration of the natural radionudide.

Long-Term lnvestigation of the Tritium
　Transport in the Saturated Aquifer

　Tzu-Xven xvang and Jih-Hung Chiu
　　　　　Health Physics Division
lnstutute of Nuclear Energy Research
　　　　　　　Republic of China
The low-level radioactive liquid waste was collected and processed by a chemical preciPotation system in the lnstitute of Nuclear Energy Research (INER).The treated water is pumped into seepage ponds and let the liquid waste Penetrating into the saturated aquifer and being diluted by the groundwater.Becausethe liquid waste contains a lot of tritium which without be absorbed by soil or rock， the saturated aquifer since 1977. Now we
can exactly predict the distribution of tritium and the dispersive Property of groundwater in the saturated aquifer.
Long-Lived Artihcial Radionudides in
　　　　　　　　Environment

　　　　　　　　　　　Masayoshi Yamamoto
Low Leve1 Radioadivity Laboratory, Kanazaxvauniversity
　　　　xva,ke、Tatsunokuchi，lshikawa 923-12， Japan
　Long-lived radionuclides have been measured for various kinds of environmental samples particularly emphasisonalpha-ray emitters : air-borne dusts， rain waters， ground surface soils， coastal and lake sediments， foodstaffs etc. All samplesare subycted nrst tonon-destructive gamma spectrometry to know the level of Cs-137，which provides very useful information on the concentrations of transuranic nudides and Tc-99. Pu-isotopes， Am241，natural u and Th-isotopes， Ra-226 and Po-210 a,re measured by alpha spectrometry，and extremely low leve1 NP-237 and Tc-99 by high resolution ICP-MS after chemical separation and purification using solvent extraction and/or ion exchange techniques.　lt was found that activity ratios relative to Cs-137 and/or to Pu-239+240 depend highly on the environmental circumstance.Results of obtained for various environnlental samples will be presented together with the chemical Procedures developed for ICP-MS measurernents of extremely low-1eve1 Np-237 and Tc-99.