ML20115K141

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Aerial Radiological Survey of Saxton Nuclear Experimental Corp Facility & Surrounding Area Saxton,Pa
ML20115K141
Person / Time
Site: Saxton File:GPU Nuclear icon.png
Issue date: 10/31/1991
From: Clark H, Hoover R, Mitchell C
EG&G, INC.
To:
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ML20115K054 List:
References
EGG-10617-1132, NUDOCS 9607250237
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  • ENERGY MM RtEMENTS ATTACHMENT 2 l

i REFERENCE 5 OUS @ESTION 78 ESPONSE EGG-10617-1132 UC-702 OPERATED FOR THE U.S.

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OCTOBER 1991 DEPARTMENT OF ENERGY BY EG&G/EM -

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i l AN AERIAL RADIOLOGICAL SURVEY OF THE l

4 SAXTON NUCLEAR EXPERIMENTAL l

I CORPORATION FAC'LITY i

! AND SURROUNDING AREA l i .

SAXTON, PENNSYLVANIA e-i t

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9607250237 960718 ^^TE OF SURVEY: JULY 1989 PDR ADOCK 05000146 P PDR 0

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i l' j l . DISCLAIMER i

i . This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Govemment nor any agency thereof, nor any of their employees.

! makes any warranty, express or implied, or assumes any legal liability or responsibility 8or the accuracy, I completeness, or usefulness of any information, apparatus, product,,or process disciosed, or represents 4

I that its use would not infringe privately owned rights. Reference herein to any specific commercial -

product, process, or service by trade name, trademark, manufacturer, or.otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Govemment or

any agency thereof. The views and opinions of authors expressed herein do not necessarily state or i j reflect those of the United States Government or any agency thereof. '

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5 This report has been reproduced directly from the best available copy.

Available to DOE and DOE contractors from the Office of Scientific and Technical Information, P.O. Box 62.

Oak Ridge, Tennesse 37831; prices available from (615) 576-8401, FTS 626-8401.

Available to the public from the National Technical information Service, U.S. Department of Commerce.

5285 Port Royal Road, Springfield, Virginia 22161.

1 j ..

4 dsees ENERGY MEASUREMEN7S EGG 10617-1932 OCTOBER 1991 i

p .

l AN AERIAL RADIOLOGICAL SURVEY OF THE ,

4 l- SAXTON NUCLEAR 4 i EXPERIMENTAL l l CORPORATION FACILITY {

) AND SURROUNDING AREA i SAXTON, PENNSYLVANIA i

(

i DATE OF SURVEY: JULY 1989 j i I i

R..A.. Hoover  !

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! Protect Scientist l l i

( REVIEWED BY i

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! h==y M A A g

~

I H. W. Clark, Manager /

i Nuclear Radiation Department i

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This Document is UNCLASSIFIED

$.? N C. K.' Mitchell . i Classification Officer .

l This work was performed by EG&G/EM for the United States Nuclear Regulatory Commission through an EAO transfer of funds to Contract Number DE-AC08 48NV10617 with the United States Department of Energy.

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- ABSTRACT 1

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  • An serial radiological survey was conducted during the period July 5 to 22,1989, over an 83-square-1 kilometer (32-square-mile) area surrounding the Saxton Nuclear Experimental Corporation (SNEC) facility which is owned by General Public Utilities and located near Saxton, Pennsylvania. The survey was conducted at a nominal altitude of 61 meters (200 feet) with line spacings of 91 meters (300 feet). A 3

l contour map of the terrestrial gamma exposure rate extrapolated to 1 meter above ground level (AGL)

was. prepared and overlaid on an serial photograph and a set of United States Geological Survey .

J (USGS) topographic maps of the area. The terrestrial exposure rates varied from about 9 to 11

! microroentgens per hour (pR/h) over most of the survey area. The levels over the SNEC facility did not i differ from the exposure rates seen over the entire survey areac Casium-137 (Cs-137) levels typical of worldwide fallout deposition were detected throughout the surveyed area. No other trends of Cs-137 were observed, l

Soil samples and pressurized ion chamber measurements were obtained at six' locations within the f

i survey boundaries to support the serial data.

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CONTENTS l

Abst ract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ll 4

Sections -

1.0 l ntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2.0 Site Descnption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 3.0, Natural Background . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . 1 4.0 Su rvey Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .' . . . . . . . . . . . . . . . . . . . . . . . 3 5.0 Survey Ecuipment ................................................ 3 5.1 R EDAR IV System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 5.2 Helicopter Positioning Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 6.0 Data Processing Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 5 7.0 Data Analyses .................................................... 6 7.1 Groes Count Procedure .......................................... 8 7.2 Man-Made Gross Count Extraction Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 7.3 Cessum-137 Gross Count Extraction Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . 7 8.0 Ground-Based Measurement Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 9.0 Discussion of Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 9.1 Terresthal Gamma Exposure Rate Contour Map .......................... 7 9.2 Cesium-137 Count Contour Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 l

l 9.3 Ground-Based Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 10.0 S u m mary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figures 1 General View of the Saxton Nuclear Experimental Corporation Facility and Surroundmg Area Showmg the Facilities. Survey Boundary, and Ground Samp6e Sites for the 1989 Aerial Survey .................................. 2 l 2 MBB BO.106 Helicopter with Detector Pods ................................ 3 3' REDAR IV Processor System Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4 REDAR IV Data Acquesstion System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . '5 5 Intenor of the Mobile Data Analysis Laboratory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 lil

l 6 Block Diagram of the REDAC System . . . . . . . . . . . . . . . . . . . . . ............... 6

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. 7 Terrestrial Gamma Radiation Exposure Rate Contours Derived From Aerial

, Data Obtained during July 5-22,1989, Over the Saxton Nuclear j Expenmental Corporation Facility and Surrounding Area . . . . . . . . . . . . . . ..,,. . . 3 l 8 Gamma Ray Energy Spectrum Typical of the Natural Background in the

,' Survey Area . . . . . . . . . . . . . . . . . . ............................,,,,,,, g i .

l Tables 4

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1 REDAR IV Spectral Data Compression . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . , , , , , , 4

! 2 Results of Soil Sample Analysis (Average Values) . . . . . . . . . . . . . . . . . . . . . . . . , , , , ,

g 3 3 Compenson of Aerial and Ground-Based Measurements . . . . . . . . . . . . . . . . . . . . . . . . 10 i

j References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ......... .... 11 l iv

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1.0 INTRODUCTION

3.0 NATURAL BACKGROUND i The United States Department of Energy (DOE)' Natural background radiation originates from i maintains the Remote Sensing Laboratory (RSL) radioactive elements present in the earth, air-

in Las Vegas, Nevada. and an extension facility borne radon, and cosmic rays entering the j in Washington, D.C. The RSL is operated under earth's atmosphere from space.
' contract to the DOE by EG&G Energy Measure-

{ ments. Inc. (EG&G/EM). One of the major func- The natural terrectrial radiation levels depend j tions of the RSL is to manage an serial surveil- upon the type of soil and bedrock immediately

! lance program called the Aerial Measuring below and surrounding the point of measure- -

! System (AMS). ment. Within cities, the radiation levels are Since its inception in 1958. the AMS has. con- also dependent on the elemental composition of street and building materials. The gamma

! tinued a nationwide effort to document baseline radiation originates pnmarily from the uranium

! radiological conditions surrounding nuclear decay chain, the thorium decay chain, and i energy-related sites of interest. These sites radioactive potassium. Local concentrations of l include power plants, manufacturing and pro- these nuclides produce radiation levels at the

! cessing plants, and research laboratories . surface of the earth typically ranging from 1 to i employing nuclear materials. At the request of 15 gR/h (9 to 1.300 mrom/y).1 Areas with

} federal or state agencies and by direction of the j DOE. the AMS is deployed for various serial esWah @ wanWm anh hum con-survey operations.

centrations in the surface minerals exhibit even higher radiation levels.

i An aerial radiological survey, performed at the request of the United States Nuclear Regulatory Cesium-137 is another radioactive element j Commission (NRC), was conducted from July which is found in many parts of the world.8 it 5-22, 1989, over the Saxton Nuclear is a product of nuclear fission. Generally, Cs-

! Experimental Corporation (SNEC) facility and 137 is due to worldwide fallout resulting from

!- surrounding area (Figure 1). The survey covered the atmospheric testing of nuclear weapons, i an 83-square-kilometer (32-square-mile) area Values of less than 1 picocurie per grantof soil

around the plant. The purpose of the survey was (pCl/g) are considered normal, although i to map the gamma environment of the area higher values have been reported.8

! surrounding the SNEC Facipty. Particular atten-

. tion was to be paid to the oossible presence of Redon, a radioactive noble gas; is a member of l 1 cesium-137 (Cs-137) in the areas surveyed. both the uranium and thorium decay chains. It I can both' diffuse through the soll and travel

! through the air to other locations. Therefore,

! 2.0 SITE DESCRIPTION the level of airborne radiation due to these i . radon isotopes and their daughter products at The SNEC facility is located in Saxton, any specific location depends on a variety of l

i Pennsylvania, about 32 kilometers (20 miles) factors including the meteorological condi-

southeast of Altoona, Pennsylvania. The plant is tions, mineral content of the soil, and soil
located in a narrow, deep valley whose sedes permeability. Typically, airborne radiation con-j rise up 152 meters (500 feet) from the valley triliutes from 1 to 10 percent of the natural floor. Elevations in the survey area range from a background radiation levels.

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minimum of 213 meters (700 feet) in the central j . portion of the survey area (along the banks of Cosmic rays, the space comporst t, interact the reservoir which runs down the center of the with elements of the earth's atmosphere and 4

survey area) to over 610 meters (over 2,000 feet) soil: These interactions produce an additsonal i

in sewal parts of the sumy area. natural source of gamma radiation. Radiation Large-area serial photographic imagery of the levels due to cosmic rays vary with altitude

plant, taken by EG&G aircraft, were used in and geomagnetic latitude. Typically, values preparing this report. In addition, many oblique range from 3.3 gR/h at sea level in Florida to
aerial photographs of the site were taken during 12 gR/h at an altitude of 3 kilometers (1.9 the survey. miles) in Colorado.4 l

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't FIGURE 1. GENERAL VIEW OF THE SAKTON NUCLEAR EXPERIMENTAL CORPORATION FACILITY AND SURROUNDING AREA SHOWING THE FACILIllES. SURVEY BOUNDARY. AND GROUNO SAMPLE SITES FOR THE 8909 AERIAL SURVEY

4.0 SURVEY PLAN outputs from eacn octector were combined in a four-way summing amplifiar for eacn array. Then The survey was designed to cover approximately outputs of each array were matched and com-83 scuare kilometers (32 square miles) surround-bined in a two-way summing amplifier. Finally, ing the SNEC facility (Figure 1). The gamma ray spect*al data were processed to provide both a the signal was adjusted in the analog to digital converter (AOC) so that the calibration peaks cualitative and Quantitative analysis, where appli- appeared in preselected channels of the multi-caDie, of the radionuClldes in the survey area. Channel analyzer of the REDAR IV system.

l The helicopter steering computer was program-med to guide the aircraft through a series of - I parallel flight lines wnich would emcompass the area surrounding the site. For this survey, all 5.1 REDAR IV System lines were flown in an approximately north- The REDAR IV is a multimicroprocessor, porta-south direction at a nominal altitude of 61 ble data acquisition and real-time analysis sys-meters (200 feet) above ground level (AGL) a tem. It has been designed to operate in the line spacing of 91 meters (300 feet), and a speed severe environments associated with platforms of 36 meters /second (70 knots), such as helicopters, fixed-wing aircraft, and var-l ious ground-baseo venicles. The system displays to the operator all required radiation and system 5.0 SURVEY EQUIPMENT information, in real time, via CRT displays and multiple LED readouts. All pertinent data are A Messatsenmitt Bolkow Blohm (MBB)80-105 recorded on magnetic cartridge tapes for post-helicopter (Figure 2) was used for the low alti. mission analysis on minicomputer systems.

tude survey. The aircraft carried a crew of two The system employs five Z-80 microprocessors and a hghtweignt data acquisition system called with AM9511 aratnmetic processing chips to per-the Radiation and Environmenta! Data AcQuist-tion and Recorder system. Model IV (REDAR form data collection and display. real-time data IV). Two pods-each containing an array of four analysis, navigational calculations. and data recording, all of wnich are under operator con-10.2-cm x 10.2-cm X 40.6-cm (4-in x 4-in X 16-in) log-type, thallium-activated, sodium iodide, trol. The system allows access to tne main pro-Nal(TI). gamma detectors as well as one 10.2- cessor bus through both serial and parallel data ports under control of the central processor.

em x 10.2-cm cylindrical gamma detector of the same material-were mounted on the sides of The system consists of the following sub-the hekcopter. The smaller detector extends the systems:

effective dynamic range of the REDAR IV sys- 1. Two independent radiation data collection tem, wnich is useful in examining areas exnibit- systems ing enhanced levels of radiation.

2. A general purpose data 1/O system
3. A digital magnetic tape recording system
4. A CRT display system I 5. A real-time data analysis system
6. A ranging system with steering calculation and display 9 ,

The REDAR IV processing system block dia-gram is shown in Figure 3.

s Each radiation data collect an system consists of a multichannel analyzer whien collects 1.024 cnannels of gamma ray spectral data (4.0 kev /

channel) once every second during the survey FIGURE 2. Aess ad f 05 NEL/CoPTEA WITH OETECToA pops operation. The 1,024 channels of data are sent to the single-channel processor, then compressed The signal from each detector was calibrated into 256 channels. Table 1 summarizes tne spec-with a socium 22 (Na-22) source. Normalized tral data compression performed by REDAR IV 3

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Table 1. REDAR IV Spectral Data Compression

)4 Ey (kev) Output Channel

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At input input Channel Output Channel Energy Coefficient j Channel Center (lineer 9 4 kev / channel) (comproceed) AE (kev / channel)

O- 300 0- 75 0 - 75 4 f 304 - 1,620 76 - 405 76 - 185 12 1,624 - 4,068 406 - 1,017 186 - 253 36 4,072 - Cutoff 1,018 - 1.023 254 N/A l

j 255 (always zero) i 3 The spectrum is divided into three partitions stripping of low-energy photopeaks, such as the l with the appropriate energy coefficient to make 60-kev photopeak f rom americium-241 the width of the photopeaks approximately the (Am-241). The spectral compression technique l reduces the amount of dets storage required by

same in each partition. The resolution of Nal(Tf) a factor of four.

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crystals varies with energy, permitting the com-pression of the spectral data without comprom-ising photopeak identification and peak strip- The 256 channels of spectral data are continu-

] ously recorded every second. The REDAR IV J ping techniques. In the first partition (Channels i 0-75), the data are not compressed to permit system has two sets of spectral memories; each l

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msmory can accumulate four individual spectra. The radar altimster similarly measured the time The two memories are operated in a flip-flop lag for the return of a pulsed signat and con-mode, every 4 seconos, for continuous data verted this delay to aircraf t altitudes. For accumulation. W9:le one memory is being used altitudes up to 610 meters (2.000 feet), the to store data, tne data in the otner memory are accuracy was = 0.6 meter or 2 2 percent. which-ceing transferred to magnetic tape. ever was greater. These data were also recorded on magnetic tape so that any variation in gamma The REDAR IV data accuisition system is shown signal strength caused by altitude fluctuations

'n Figure 4 could be compensated.

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. _. T .. .. used to record the data are described in consic-E. . .- _ _ ', erable detailin a separate publication.5

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i@i , 6.0 DATA PROCCSg NG EQUlPMENT

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E hy, Radiation and Environmental Data Analyzer and Computer (REDAC) system. This system consists p j p:

E  ! of a computer analysis laboratory mounted in a 4- f..l mobile van (Figure 5). During the survey opera-

  • -- tions, the van and aircraft were based at the Blair E5555555E 5533 County-Altoona Airport.

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FIGURE e. REDAR IV DATA ACQUISITION SYSTEM 5.2 Helicopter Positioning Method /

The helicopter position was established by two systems: an ultranigh-frecuency ranging system -*

(URS) and a radar altimeter.

F8GURE s. INTERIOR OF TNE MoalLE DATA ANALYSIS The URS master station, mounted in the heli- LAmoRAToRY copter, interrogated two remote transponders located outside the survey area. By measunng the roundtrip propagation time between the The REDAC system has a 16-bit CPU with 512 master and remote stations, the master unit com- kilobytes of memory and floating point proces-puted the distance to each. The distances were sor; two discs with a total of 1.1 gigabytes of recorded on magnetic tape with the radiation storage; two 800/1.600 byte-per-inch. 9-track, data, once each second. Simultaneously, these 1/2-inch tape drives; two 4-track 1/4-inch car-distances were converted to position coordinates tridge tape drives for reading REDAR IV tapes; a for the steering indicator to direct the aircraft 36-inch-wide carriage incremental plotter; a along the predetermined flight lines. multispeed printer; a system CRT display; and 5

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l three alpha / graphics CRT displays and hard- in the area surrounding the plant and locating copy units (Figure 6). An extensive library of and identifying any anomalous sources of man- l software is available for data processmg. made radiation, particularly Cs-137. Isooteth l l j maps were produced using three different pro-j cedures: gross count procedure, man-made gross count extraction procedure, and Cs-137 l

4 l manticTart u ns"em ea e ric Wg count extraction procedure. Only the gross I

    • ""**"' count isopleth is presented in this report. l 1

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The gross count (GC) method was based on the l l

integral counting rate in that portion of the spec- l

) "nasses"PT trum between 38 and 3,026 kev. The count I teuru un i y,fg?j,*," " "

courvTta matutsfis rate (measured at survey altitude) was convert-

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ground level by application of a predetermined j conversion factor. This factor assumes a uni-

! 887&""# formly distributed scarce covenng an area which l unest stana. - est aam is large compared with the field of view of the l NY "ad'*"""

PtsTTis' detector (approximately 100- to 200-meter dia-

! meter circle at the survey altituoe of 61 meters).

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pcmese 7.2 Man-Made Gross Count Extraction j g,8,=c manamn Procedure j The man-made gross count (MMGC) extraction l Piouns a. stock DIAGAAar oF 7NE NaDAC SYs7E4f algorithm is designed to reveal the presence of

! changes in spectral shape. Large changes in

! gross counting rates from natural radiation i Gamma spectral windows can be selected for usually produce only small changes in spectral i any portion of the spectrum. Weighted combina* shape. The natural emitters will change intensity j tions of such windows can be summed or sub- of radiation emitted, but the spectral shape will

} tracted and the results plotted as a function of remain nearly constant. As the detector moves i time or distance. By the proper selection of from one location to another, the value of the

) windows and weighting factors, it is possible to ratio of the counts in the high energy portion of

extract photopeak count rates for radioisotopes - the spectrum to the low energy counts remains l deposited on the terrain by human activity. The approximately constant. The algorithm is design-j photopeak count rates can then be converted to ed to be most sensitive to man-made nuclides.

j isotope concentrations or exposure rates. The spectrum dividing (ine is chosen at an energy (1,394 kev) above which most long-lived.

The REDAC can display the spectral data on a man-made nuclides do not emit gamma rays. It CRT or plot it on an incremental plotter for is analytically expressed as:

+

isotopic identification and documentation.

1.384 key 3,024 key 7.0 DATA ANALYSIS MMGC = counts - K. counts i in general, the serial radiation data consist of E = 38 kev E = 1,394 kev contributions from naturally occurnng radio-i elements, aircraft and detector background, and j cosmic rays. For this survey, the major emphasis Counts in the upper energy window (1,394 to was on mapping the terrestrial gamma radiation 3,026 kev) are multiplied by a constant. K.,

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l ,. which is the average ratio of counts in the low soil samples were dried and their gamma activi-4 energy window to counts in the high energy ties measured using a germanium-based detec-window for areas of normal background. The tor system located at EG&G/EM's Santa Barbara l

resultant MMGC is approximately equal to zero laboratory. Detailed descriptions of the systems 1

for areas containing normal background radia- and procedures used for soil sample data collec-j tion and significantly different from zero in those tion and analysis are outlined in separate l

4 areas which have contributors in addition to publications."

background radiation. The MMGC analysis did not show any statistically significant anomalies. ,

9.0 DISCUSSION OF RESULTS 7.3 Cesium-137 Gross Count Extraction 9.1 Terrestrial Gamma Exposure Rate j Procedures Contour Map i

! The Cs-137 extraction procedure is very similar The principal result obtained from the gamma ,

I to the man-made gross count algctithm. Two survey of the SNEC facility is the terrestnal l windows are used for the Cs-137 extraction pro- gamma exposure rate contour map (Figure 7) of I cedure. The low energy window is set to encom- the 83-equare-kilometer (32-square-mile) area )

pass the Cs-137 photopeak, which occurs at 682 surrounding the plant. The mao represents the  !

l j MeV. This window encompasses an energy range measured terrestrial gamma exposure rate plus i of 590 kev to 722 kev. The high energy window an estimated cosmic component (3.8 uR/h) at 1  !

is used to infer the contributions of other meter above the earth's surface. The highly vari-sources to the counts in the Cs-137 window, able airborne radon daughter component'is not The ranges used were 722 kev to 794 kev. included.

Mathematically this can be expressed as:

! the map in Figure 7, range from less than 7 yR/h 722 mey 794 tev over the Rayestown reservoir to 11 to 15 pR/h over other portions of the survey area. No areas I

! Cs-137 = counts: - E counts of exposure rates greater than 15 pR/h were i

obtefved.

E = 500 tev E = 722 kev Aerial systems integrate radiation levets over an area whose diameter may be several times the Where K. is analogous to K. In the previous height of the platform above ground. This is a

'9"" function of gamma ray energy, their birth within l

! the soil matrix. and the response charactenstics I of the detector package. For activity fairty uni-

! 8.0 GROUND-SASED MEASUREMENT formty distributed over large areas (typical of PROCEDURES natural background radiation), the agreement l

' between ground-based readings and those infor-i Exposure rates were measured and soil samples red from aerial data is generally quite good.

! obtained at five locations during the SNEC sur- However, for nonuniform areas, the averaging l voy to support the integrity of the serial results. inherent in serial measurements will underesti-I The beations of the ground-based measure- mate activity directly over anomalies and will overestimate activity immediately surrounding

) monts (see Figure 1) were chosen on the basis of assumed normal background radiation levets and these anomalies. For such conditions, ground i

j were away from any otmous anomalies. A Reuter- and serial measurements will not agree. While j Stokes pressurized ionization chamber was useo the serial data serve to locate such anomalies, for each exposure measurement. Measurements ground measurements are required to better I were made at a height of 1 meter eNWe ground ~ define the activity and spatial extent of the j level (AGL). Soil samples, to a depth of 15.0 cm. anomalies.

i were also obtained at the center and at four i points of the compass on the circumference of a Figure 8 is a typical background spectrum for l 99 cza surrounding the SNEC facility.

200-meter (660-foot) diameter circular area. The

.i 7

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l FIGURE 1. TERRESTRIAL GAMMA RADCATION EXPOSURE RATE CONTOURS DERIVED FRON AERIAL DATA OCTAINED DUntNG JULY 5-21, 1909, OVER THE SAKTON NUCLEAR EXPERINENTAL COR9 ORATION eAClllTY AND SURROUNDING AREA

1 1

i j .mx . 9.3 Ground Based Measurements

,s*,. Pressurized ion chamber measurements and soil l _

/ samples were collected during the survey at six

-es . om sites within the survey boundanos. The site loca-i l

l " '*

! .,[,%, tions (Numbers 1 through 6) are labeled in

! I  ;,

j " , .e, Figure 1. The soil samples were dried and

. counted on a calibrated gamma spectrometer in

[ " }l .s . .c od . y'=-*N.

the laboratory. The soil analysis exposure rates

[ ] were computed from the primary isotopic con-l l

0  ; \ k,,,,,cr,7., 4*,, centrations in the soil samples and included the j\ * ' " * =. /

effect of soil moisture (see Table 2). The mes-

, .dQ -2 *'a => sured soil exposure rate values are compared j ", ,,,, ,,,,, . ,,,,, with the s,on chamber measurements and the l .. aerial measurements in Table 3. These exposure l Fleums s. GAAfAIA AAY ENf40Y s#fCTRUef TYPfcAL values repmeent h hl plus the cosmic

of TNE NATURAL aACKQRoUNo M THE components onW s w tY N The isotopic and ion chamber measurements 4

' generally agree with the inferred senal data for i

9.2 Cesium-137 Count Contour Analysis each site. There are several contributors to dif-forences among the measurement methods:

f A computer-sided search of the data for man-made sources, particularly the gamma-emitting 1. The serial data were not taken at exactly j the same places and times as the ground

radionuclide Cs-137, indicated the presence and data.

l distribution of Cs-137 activity typical of world-i wide fallout. None of the investigations revealed 2. Each 1-second data point obtained with trends that suggest dispersal of Cs-137 via par- the airborne system covers an area several

ticulate transport during contaminated waste thousand times as large as a measurement l burning, hauling, or storing. The Cs-137 activity made at 1 meter, such as with a portable
inferred from serial data was well within that ion chamber.

l expected from the deposition of woldwide fall-l out, which is approximately 1 pCugram of soil 3. Since only a limited number of soil

or less. No other man-made contaminates were samples were taken, statistical deviations 5

detected in this area. are significant.

i i

Table 2. Results of Soil Sarnple Analysir (Average Values)

I Seu l Meisture U 238 Th-232 Ca 137 K-40

! Sitet (%) (ppm) (ppm) (pCl/g) (pCl/g) i

! 1' 20 t 6 3.4 i 0.7 11 i2 0.3 10.1 12 i 2 s

i 2 23 i 6 2.9 0.3 8 1 0.3 1 0.1 8*2

! 3 19 3 3.1 0.2 11.9 0.6 0.4 t 0.3 18 i 4 1 4 16i4 3.1 0.2 12 1 0.18 i 0.05 20 t 4 3 2 2 3 E 5 .

e i 6 25 t 1 3.5 0.7 11 1 0.27 0.02 14 & 1 i ' Site Description 3 She 1: Fie46. s inches et grase, pieyground Site 4: Field. 6 inenes of grene.16med 4 years ago Site 2: Feliour corn fieed.1-2 incnes of wesos and press Sne s: Ene of wood peer over Joneste River j Sne 3: Cemetery. west asee Sne s; Festa,3 L 7ee of grues and wooos

} a No sod esmotes tason.

i 9 l

1 i

Table 3. Comparison of Aerial and Ground-Dased i Measurements

! Exposure Rate (un/h at 1 Meter Above Ground Level) l

! Sample som ion inferred Location 1 Ano6ysis** Chambord Aertal Datas l

l G-1 to = 1.6 9.8 1 0.5 7- 9 i G-2 9 1.3 8.0 i 0.5 9 - 11 G-3 11 ~1.3 11.0 0.5 9 - 11 l

! G4 12 1.6 11.7 t 0.5 9 - 11

! G-5 5 5.4 1 0.5 7- 9 G-6 10.3 i 0.8 11.0 0.5 9 - 11 isite seceuono are snown in Figure 1 seascuieuon inesuces cosme rey conenevuon of 3.s uR/h.

3calcuestion incluees a mosture correcuan of the Form 1/(1+m).

  • Meuter stokes Moest No. ass III. Senal No. R3sts 8No sosi esmosos taken.

l

4. The ground cover may reduce the com- of Cs-137 which is dependent on the soil i puted isotopic exposure by as much as 5 depth. Any deviations in the soil profile percent. would result in different measured con-
5. Site S-1 was located in an area who,, centrations of Co-137 conditions were changing, hence the 3. Cesium-137 is not necessarily homo-aenal system did not nicasure a homo- geneously distributed.

geneous sample.

6. Site S-5 was on the banks of the reser-voir. The senal system measured both the 10.0

SUMMARY

conditions over the reservoir and the sur-rounding terrain. An serial radiological survey was conducted between July 5 and 22.1989, over an 83-Differences in Cs-137 concentrations reported square-kilometer (32-square-mile) area sur.

in this survey and a previously conducted rounding the Saxton Nuclear Experimental ground surveys are not great. Some higher Corporation facility located near Saxton, readings were reported in the ground survey. Pennsylvania. The survey was conducted at a This can be attnbuted to a number of factors: nominal altitude of 61 meters (200 feet) with

1. The ground survey intentionally chose line spacings of 91 meters (300 feet). A con-survey sites which were most likely to tour map of the terrestrial gamma exposure have retained Cs-137 fallout. rate (extrapolated to 1 meter above ground)
2. The previous survey measured the sam- was prepared. The Cs-137 activity inferred pies in sits: soil samples for this survey from serial data was within the limits of the were removed from the field and then deposition from worldwide fallout. No other analyzed in a laboratory. The in sits tech- man-made contaminates were detected in the nique assumes an exponential distribution survey area.

10

i REFERENCES

i i

i 1. Lindeken. C.L. et al.1972. " Geographical Variations in Environmental Radiation Background in the

Umted States," Proceedings of the Second International Symposium on the Natural Radsasson Environment,7-11 August 1972. Houston, Texas
pp 317-332. Springfield. VA:

l

National Technical Information Service. U. S. Department of Commerce. .

} 2. NCRP Report No. 52. Cesium.137 From the Environment to Man: Metabolism and Dose. National 1

Council on Radiation Protection and Measurements,7910 Woodmont Avenue, Washmgton.

l D.C. 20014.

! 3. Arnalds. O., N.H. Cutshall, G.A. Nielsen. Decemb1r 1989. " Cesium-137 in Montana Soils " Health Physics Vol 57, No. 6. pp 955-958.

l b 4. Kiement. A.W., et al. August 1972. Estimate ofIonising Radiation Doses in the United States 1960 2000. U.S. EPA Report ORD/DC72-1. Washington, D.C.: Environmental Protection Agency.

l 3

) 5. Boyns. P.K. July 1979. The Aerial Radiological Measuring System (ARMS): Systems, Procedures

sad Sensitivity. Report No. EGG-1183-1691. Las Vegas, NV
EG&G/EM.

l 6. Mohr, R., A.E. Fritzsche, and L Franks.1976. Ground Survey Procedures. Report No. EGG-1183- l

  • 2339. Santa Barbara. CA: EG&G/EM. l
7. Quam. W., and K. Engberg. October 1978. Low Background Ge(Li) Detector with Anticoincidence Nel Annulus. Report No. EGG-1183-2326. Santa Barbara. CA: EG&G/EM.

j 8. Hoover, R.A. September 1990. In Situ Survey, General Public Utsistses Facility and Surroundsng j Area. Report No. DOE /ONS-8806. Las Vegas, NV: EG&G/EM.

b i

1 i

4 i

i 4

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1 11 n - , - - ,

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! SAXTON NUCLEAR 1 EXPERIMENTAL CORPORATION FACILITY I SAXTON PENNSYLVANIA j EGG-108171132

DATE OF SURVEY
JULY 1900 l DATE OF REPORT: OCTOBER 1991 i
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