ML20059D150

Environ Radiation Surveillance Rept for Jul 1989 - Jul 1990

ML20059D150
Person / Time
Site:	North Carolina State University
Issue date:	07/31/1990
From:	Harris R North Carolina State University, RALEIGH, NC
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References
NUDOCS 9009060109
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Text

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RADIATION PROTECTION OFFICE NORTH CAROLINA STATE UNIVERSITY

! ENVIRONMENTAL RADIATION SURVEILLANCE REPORT I FOR THE PERIOD  ;

JULY 1989 JULY 1990 1

1 4i l

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RALTON J. HARRIS I

ENVIRONMENTAL HEALTH PHYSICIST I

l 9009060109 900831

{,DR ADOCK 05000297 PDC 1

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1. INTRODUCTION During Janisary 1990 the Ge(U) detector, which had been used by the Environmental Radiation Survel!!ance Laboratory (ERSL) since 1973, became inoperable and necessitated the use of contracted anaYsis and counting assistance from NCSU Nuclear Services in Burlington Laboratories. On June 27, 1990 the old detector system was replaced by a High Purity Coaxial Germanium Detector and lead shield purchased from Canberra instruments. Also during this period a new air sampling monitor has

' been evaluated as a possible replacement for the existing system, The new sampling system,if adopted, would allow more accurate determination of the total air volume sampled and provide greater operational reliability than is presentY available.

During 1989 the ERSL became a participant in the U.S. EPA Environmental Laboratory intercomparison Studies Program. The results of several quality control measurements are included in this report in Section 7.

In July 1990 the ERSL was given a surplus Ge(U) detector and dewar by the Carolina Power & Light Company, Shearon Harris Plant. This will serve as a backup system for the recently purchased HPGe detector.

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2. AIR MONITORING (TABLES 2.1,2.2, AND 2.3: FIGURES 2a THRU 2f)

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! Table 2.1 gives the locations of the campus air monitoring stations. Table 2.2 g}ves LLD valves for i

' several gamma emitters which would be indicators of fission product releases. Data for the period 01/09/90 to 02/06/90 is misa:ng from Table 2.2 due Instrumentation problems with the GE(U) detector. From 02/06/90 to 07/17/90 all gamma spectral analysis was performed by another laboratory.

l l During several weeks of this period gamma analysis indicates the presence of very low levels of i

Co 60, CS 137, and Ce 144. Both Os 137 and Co-60 can be present in air samples as residual l

f allout actMty. The reported Ce 144 (l 1/2 = 285 days) actMty is quite small, and if authentic may be a previously undetected remnant of the Chernobyl accident which occurred on April 26,1986.

While the absence of measurable actMties of associated short lived fission products such as Zr 95, Nb 95, and Ru 103 does not definitely preclude the possibility of Ce 144 actMty, it does support the important conclusion that there has not been a local release of radionuclides. This is further substantiated by negative results of l 131 monitoring (LLD.10 fCl m 3). Table 2.3 gives a listing of Regulatory Limits, Atert Levels, and average North Carolina background actMty levels for those radionuclides for which data is available.

Figures 2a 2e give a graphical representation of gross beta actMties determined for each monitor station instances of operational and equipment difficuttles are indicated by ' Missing Data". Figure 2f allows a comparison of Individual monitor stations on a week to week basis. The campus wido gress beta actMty averaged 17 fCl m 3 during this reporting period and is well below the Alert Level of 500 fCl m 3 TABLE 2.1 LOCATION OF AIR MONITORING STATIONS SHE DIRECTION 1 DISTANCE 2 FI FVATION3 (meters) (meters)

BROLORON SOUTHWEJT 125 17 DAVID Cl. ARK LABS WEST 500 18 LIBRARY NORTHWEST 192 +11 RIDDICK SOUDEAST 99 14 WITHERS NORTHEAST 82 6 1

DIRECTION-DIRECTION FROM REACTOR STACK D' STANCE DISTANCE FROM REACTOP STACK 3

ELEVATION ELEVATION RELATIVE TO THE TOP OF THE REACTOR STACK 2

_ . . _ _ . . _ _ _-_ _ , - _ _ ~

O TABLE 2.2 AERIALLY TRANSPORTED GAMMA ACTIVITY (fCi m ~3)

NUCLIDES SAMPUNG PERK)D Co-57 Co-60 Nb-95 Zr-9 5 Ru-103 1989 Ru-106 Cs-137 Co-141 Ce-144

07/05-07/11 <2.2 <1.7 <1.9 <3.0 07/11-07/18 <1.8 < 15.0 .

1.5 1.3 1.4 2.4 < 1.9 <4. 7 <17.9 1.6 10.8 07/18-07/25 1.5 12 1.3 2.2 13 3.9 L 12.6 1.4 103 i

07/25-08/01 2.1 1.7 1.7 3.0 1.9 i 0.5 3.3 12.1 1.8 14.7 08/01-08/08 2.2 1.9 1.8 3.1 2.5 0.7 42 I 1.9 17.1 O8/08-08/15 2.2 1.9 15.8 2.9 t 0.7 1.9 3.1 2.0 43 182 08/15-08/22 2.0 1.8 15.9 2.4 4.1 1.9 3.0 t .'; 18.1 j 08/22-08/29 2.2 1.7 13.7 2.0 4.0 1.7 2.8 11, 14.2  ;

08/29-09/05 1.6 1.4 14.9 1.9 3.9 1.5 2.5 1.7 15.1-09/05-09/12 1.5 12.8 1.8 1.9 3.1 1.8 '

~ 1.9 32 13.6 09/12-09/19 1.7 1.6 14.8 1.9 4.5

' 1.6 2.7 1.9 16.9 ~

-09/19-09/26' 2.0 1.9 152 2.1 3.8

" 1.9 2.9 2.0 15.4 ~

09/26-10/03 2.1 2.2 132 2.0 4.1 2.0 3.1 2.1 14.7 10/03-10/10 2.2 2.1 14 2 2.1 3.6 1.9 3.6 2.2 15.5 10/10-10/17 2.4 2.3 14.8 2.0 4.0 i

2.4 4.2 2.5 14 3 10/17-10/24 2.4 - 2.4 16.7 2.7 2.3 4.1 . 2.4 4.9 18.1 10/24-10/31 2.2 2.0 2.1 3.8

.16.5 2.5 4.7 17.6 2.0 - 14.7 10/31-11/C7 2.4 22 2.2 3.6 2.1 3.9 152-11/07-11/14 2.5 2.4 22- 13.9 23 1

2.4 4.0 2.1 33 14.4 11/14-11/21 2.5 ~23 2.1 3.7 14.3 2.4 42 15.7

! 11/21-11/28 2.2 15.1

1.8 1.9 1.7 2.4 2.6 3.8 14.9 11/28-12/06 1.7 1.5 11.1 1.7 1.8 ' 2.1 1.5 2.9 ' 12.4 1.4 12/06-12/12 1.8 - 1.9 -1.8 23 10.9 1.5 2.5 122 12/12-12/19 1.5 1.6 11.4  ;

1.6 1.3 - - 2.0 1.7 2.6 13.5 12/19-12/27 1.5 1.3 10.1 .l 1.7 1.4 2.0 1.3 22 11.9 1.4

~12/27-01/02/90 1.8 1.9 1.8 2.2 10.6 1.4 23 12.1 1.5 11.9 1.5 - 2.4 13.6 4

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O TABLE 2.2 AERIALLY TRANSPORTED GAMMA ACTIV!TY(fCi m ~3) CormNUED NUCLIDES N PERIOO_ Co-57 Co.60 Nb-95 Z r-9 5 Ru-103 Ru-106 1990 Cs-137 Ce-141 - Ce-144 01/02-01/09 1.8 1.8 1.9 2.3 1.6 01/09-01/1(. --

122 1.6 01/16-01/23 --

- 2.3 14.1 01/23-01/30- ' -

-J 01/30-02/06 --

02/06-02/13 0.1 0.7 0.8 1.7 02/13-02/20 0.5 1.0 -

2.2 2.3 3.9 2.5 -

.0.310 2 - 1.1

' 02/20-02/27 OS 2.810.4 1.6 2.5 0.9 O2/27-03/05 0.6 0.1 1.6 -

4.7 0.4 0.5 1.8 t 0.4 0.9 03/05-03/12 0.4 0.5 .

9.9 i 2.6 0.4 0.3 0.6 0.9 0.4 - 1.4 03/12-03/19 0.1 0.7 0.6 0.9 03 3 03/19-03/26 0.3 0.6 -

1.5 1 0.5 1.30.2 0.5 0.8 0.3 O3/26-04/03 0.1 0.5 --

3.7 i 0.5 a 0.8 0.6 1.0 0.4 0.6 1.4 O4/03-04/10 03 0.8 0.710.3 1.7i0.4 0.5 04/10-04/17 0.3 0.6 -

1.6 ~

2.810.3- 1.0 3.41.0 0.7 O4/17-04/24 0.4 1.5 ~

3.0 0.8to.3 1.0 2.7t0.5 1.0 1.4 0 3 .-

2.1 04/24-05/01 03 1.2iO.4 1.2 1.9 g 414,4 ,,,4 3 3,7 1

05/01-05/08 0.4 1.1 -

1.5to.4 0.9 1.8 '1.4

~ 0.7 L __

42 05/08-05/15 0.4 1.0

.0.9 02 0.8 1.3 0.6 - __

1.8 05/15-05/23 0.7 0.8t0.2 ' O.6 1.0 0.7 - 3.7 05/23-05/28 0.3 0.5 -

3.70.6 1.2 1.9 0.5 1.4 O5/28-06/05 0.4 - 1.2 --

1.20.5 1.0 1.5 1.1 0.7 __

2.8 06/05-06/12 0.5 - 3.210.4 'O.9 1.7 0,8 3.8 06/12-06/*9 0.4 0.7 --

1.90.4 0.5 1.0 1.3 1 0.3 1.0 _ --

10.3 i 1.6

! O6/19-06/27 2.2 '6.32.5 7.0 11 9 0.7 1.5 '

06/27-07/03 63 5.3 -

4.3t3.2 9.9 -17.8 32 3.8 18.6 8.0 53 3 -!

52 9,9 48.9

_ _ - _ _ _ _ - _ - _ - _ _ _ - _ _ - _ - - - - - - - _ - _ _ - - - _ _ - - _ - - - _ - - _ _ _ _ _ .-- -- - .__ - . - _ _ _ _ __ - - _ - - - - _ = _ __

TABLE 2.2 AERIALLY TRANSPORTED GAMMA ACTMW (fCi m -3)

NUCLIDES -

SAMPLING PERIOD Co-57 Co-60 Nb-95 1990 Zr-95 Ru-103 Ru-106 Cs-137 Ce-141

~

Ce-144 07/03-07/10 <2.9 5.6t3.3 <7.2 <13.6 07/10-07/17 - <5.6 <44.1 <4,3

<4.9 <23.7 4.3 4.2 52

. 10.5 4.3 . 33.8 6.9 . 6.9 33.4 1 4

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. Figure 2a 50_ .

Airborne cross seta Activity N. C. State University Campus neguiatory Limit =ioco rCi/ Cubic u David Clark Station Alert Level =500 fCi/ Cubic M July 5,1989-July 17, 1990 LLD=10 fCi/ Cubic M .

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50- Airborne Gross Beta Activity Regulatory Limit =1000 fCl/ Cubic M N. c. state university Campus Alert Levei=soo fCi/ Cubic M Riddick Station LLD=10 fCi/ Cubic M July 5,1989-July 17,1990

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Figure 2d '

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50 -- Airborne Gross Beta Activity Regulatory Limit =1000 fCi/ Cubic M N. C. ' State University Campus - Alert Level =500 fCi/ Cubic M l

Withers Station LLD=10 fCl/ Cubic M July 5,1989-July 17,1990 e40-W 1

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Airborne cross seta Activity negulatory simit=tooo tci/ cubic M j N. . C. State University Campus' Alert Level =500 fCi/ Cubic M D. ~ H. Hill Station LLD=10 fCi/ Cubic M July 5,1989-July 17,1990 40--

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e Figura 20 AIRBORNE GROSS BETA ACTIVITY FOR N. C. STATE UNIVERSITY CAMPUS FROM JULY- 5,1989 TO JULY 17,1990 .

(UNITS OF FEMTOCURIES PER CUBIC METER)

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Summer Autumn Winter Spring ,

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$ 1'O is aO R'S 3 'O 35 4 'O 45 5 'O 55 40 -

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5 'S 4 JULY DECEMBER 1989  ? O J AN U AR Y-J ULY 1990 7 11

1 t TABLE 2.3 REGULATORY UMITS, ALERT LEVELS, AND BACKGROUND LEVELS FOR -

AIRBORNE RADIOACTIVITY (ICI m 3)

REGULATCRY ALERT AVERAGE N.C.

NUCUDE LIMjI LE.EL y BACKGROUND LEVEL CRCSSAUM 20 10 4 l

GRCSSBETA 1000 500 100.

Cs 137 5 x 105 10. 2

~Ce 144 2 x 1'05 . j oo . o Ru 106 2 x 105 30 0 l131 1 x .105 10 o-4 I .

Reference:

Environmental Radiation Surveillance Report 1984 85, State of N.C.'

Radiation Protection Section 1

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3. MILK (TABLE 3.1) 1 in this reporting period Sr 90 analysis has been replaced by radiolodine analysis, and the Lake {

Wheeler Road Dairy and the Randleigh Farm Dairy have been added as control stations. '

The FDA's Preventive Action Guide (PAG) for 1131 is 1.5 X 104 pCl/ liter for infants. All analyses during tP.is period show activities at least three (3) orders of magnitude below the PAG.

The analyses are performed in duplicate and the higher value is reported in each case. Analysis of the December 1989 samples was delayed due to the holidays and this resulted in an elevated detection limit for these samples. No sample wac available in September 1989 from the Campus Creamery due to a repair operations of the processing facilities.

i TABLE 3.1- l 131 IN COWS' MILK (pCi literl .t 1 a) LLD 2 pCiliter1 pCiliter *1 QE CAMPUS CREAMERY LAKE WHEELER RANDLEIGH AUGUST 1989 3.8 1 2.0 s3.5 5.1 1 3.3 SEPTEMBER 1989 NOSAMPLE s 2.0 s 2.0 OCTOBER 1989 s 2.3 s3.9 6.8 1 2.4 NOVEMBER 1989 s 3.4 s2.3 s 3.0 DECEMBER 1989 s 5.3 s 7.5 s 7.1 JANUARY 1990 s 2.0 s2.0 s 2.0 f FEBRUARY 1990 s 2.0 s 2.0 s 2.0

MARCH 1990 s 2.0 s 2.0 s 2.0 l- APRIL 1990 s 2.0 s2.0 s 2.0 MAY 1990 s 2.6 s2.5 s 2.5 JUNE 1990 s 2.0 s 2.0 s 2.0 JULY 1990 s 2.4 s 2.4 s 2.5 13 l l

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4. SURFl.OE WATER (TABI ES 4.1,4.2, AND 4.3) - '

Table 4.1 gives the gross alpha and beta activities' for water from Rocky Branch at points where it enters (ON) and exits (OFF) the campus. The LLD values for gross alpha and beta activities are

- 0.1 pClliter1 and - 0.6 pCiliterl respectively. For gross alpha activity the Alert Levelis 5 pClliterl and the Regulatory Umit is 15 pClliter1. For gross beta activity the Alert Levelis 12.5 pClliterl and the Regulatory Limit is 50 pCiliter1. Samples with gross alpha or beta activities exceeding these Alert Levels would require gamma analysis to identify the radionuclicies '

present.; Surface water samples analyzed during this period have not shown the presence of any gamma emitters above the detection limits specified in Tables 4.2 AND 4.3.

1 i

TABLE 4.1 GROSS ALPHA AND BETA ACTIVITY IN SURFACE WATER (pCiliter1 12 a) .

'LLDa- 0.1 pClliterl LLDp - 0.6 pCiliterl  !

0C1literl G CSS G CSS IBIE LOCATION ALPHA BEIA THIRD QUARTER 1989 ON 0.3 1 0.2 . 2.8 10.4 OFF <0.26 2.4 1 0.4 i

FOURTH OUARTER 1989 ON 0.110.1 2.2 1 0.4 OFF 0.110.1 2.3 1 0.4 FIRST QUARTER 1990 ON 0.2 1 0.2 2.3 1 0.4 OFF 0.2 1 0.2 0.6 1 0.4 ,

SECOND QUARTER 1990 ON - 0.6 1 0.5 2.4 1 0.5 OFF 0.7 1 0.5 2.5 1 0.5

• LLD VALUES ARE DETERMINED QUARTERLY p

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b TABLE 4.2 LOWER UMITS OF DETECTION FOR SEVERAL GAMMA EMITTERS IN SURFACE WATER FROMNCSU ERSL ANALYSIS L

NUCLIDE LLD (oci liter 1)

Co 60 5.4 .a 2n-65 13.8 Cs 137 5.3 t

Os 134 5.9 Sr 85 - 16.7

. Ru 103 36.7 Ru 106 51.3 Nb-95 16.8 Zr 95 28.5

• LLD VALUES ARE DETERMINED OUARTERLY -

l TABLE 4.3 LOWER UMlTS OF DETECTION FOR SEVERAL GAMMA EMITTERS IN SURFACE WATER FROM

- CONTRACTED ANALYSIS BY TELEDYNE INC.

NUCLIDE LLD (oCl Litg1)'

Co 60 - 6. E00 '

Zn 65 1. E01 Cs 137 7. E00 -

Cs 134 7. E00: ,

St85 i Ru 103 8. E00 -

Ru 106 6. E01 I Nb-95 Zr 95 7 E00 1

1:

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15 1

5.= VEGETATION (TABLE 5.1 and 5.2)

The data of Table 5.1 gives gross beta actMties for grass samples collected on the NCSU Campus and silage samples collected at the Randleigh Dairy and Lake Wheeler Farm Dalry. An explanation for the larger gross beta activities observed in June 1990 is not available, but may be due to the application -

of phosphate fertilizers. Tne reported actM:!es are all below the Alert Level of 20 pCl gram *1 Table 5.2 lists LLD valvet. for several gamma emitters. No gamma activity due to any of these

! radionuclides has been observed in campus vegetation.

TABLE 5.1 GROSS BETA ACTIVITY IN CAMPUS VEGETATION 'LLD - 0.5 pCl g'1 SAMPLE DATE SAMPLE LOCATION fp.C Lg*11_c)

DECEMBER 1989 NORTHCAMPUS 3.9 0.3 DECEMBER 1989 SOUTH CAMPUS 2.2 1 0.2 DECEMBER 1989 EASTCAMPUS 3.4 1 0.4 DECEMBER 1989 WEST CAMPUS 4.3 1 0.3 DECEMBER 1989 l.AKE WHEELER SILAGE 3.4 1 0.2 DECEMBER 1989 RANDLEIGH SILAGE 2.4 0.2 JUNE 1990 NORTH CAMPUS 15.511.4 JUNE 1990 SOUTH CAMPUS 13.511.3 JUNE 1990 EASTCAMPUS 10.911.3 JUNE 1990 WESTCAMPUS -14.0 1.4 l JUNE 1990 1.AKE WHEELER GRASS 9.411.2 JUNE 1990 FMNDLElGH GRASS 11.411.3-r

• LLD values are determined semiannually i

1 16

4

-1 Table 5.2 LLD VALUES FOR GAMMA EMITTERS IN VEGETATION NUCLtDE ' I I n (oCl oram 1)

Co 60 0.74 Zn 65 1.99  ;

Cs 137 - 0.77 Cs 134 -0.88 Sn 85 1.30 Ru 103 1.66 i Nt>95 1.23 Zr 95 ~2.14 -

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6. THERMOLUMINESCENT DOSIMETERS (TLDs) (TABLE 6.1)

TLD analysis is contracted to Teledyne isotopes for determination of ambient gamma exposures. The dosimeters are CaSO4doped with dysprosium and have a manufacturer stated sensitivity of 0.5.t 0.15 mR (90% 0.L.). Exposures are integrated over a three month period at each of the five air monitor stations listed in Table 2.1 and also at the top of the PULSTAR Reactor stack. A control station is located in 214 David Clark Laboratories. Table 6.1 gives the data for these seven (7) bampling locations for the period 07/07/89 to 07/10/90.

The observed exposures are those expected to be produced by background radiations in this area of North Carolina. The data of Table 6.1 agrees well with the state wide average exposure rate of 20 mR per quarter year.

l 18

TABLE 6.1 ' ENVIRONMENTAL TLD EXPOSURES (mR/OUARTER YEAR i i o)

DATE WITHERS RIDDICK BFOUGHTON LIBRARY DAVIDCLARK PULSTAR STACK (INmOL 07/07/89-10/03/89 16.2 1.5 22.0 0.8 18.8 0.6 22.9iO.3 . 14.010.3 10.410.4 16.810.61 10/03/89-01/03/90 22.013.3 27.7i2.9 21.910.3 22.7i0.5 15.6 0.4 19.1i1.1 18.810.7 01/03/90-04/03/90 21.8i3.9 31.3i3.3 25.2 0.7 25.9 5.2.. 15.0io.9.. 10.8 1.0 '17.1 2.3' 04/03/90-07/10/90 17.9iO.5 .25.3 0.9 20.6iO.7 17.Si0.5 14.610.3 26.7iO.5 15.5io.6 '

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7. QUAllTYCCWTROLNTERCOMPARISONPROGRAM The Environmental Radiation Surveillance Laboratory of the Radiation Protection Office has participated in the U. S. EPA Environmental Laboratory Intercomparison Studies Program during this reporting period. The objective of this program is to provide laboratories performing environmental radiation measurements with caknowns to test their analytical techniques. The results of the interoomparison studies are given in Table 7,1 a l. All samples are analyzed in triplicate and reported as an average value with an experimental sigma (1s).

Appendix 1 gives an explanation of the quantities listed in the tables and an example calculation.

20

TABLE 7.1a GROSS ALPHA ACTIVITY AIR FILTER INTERCOMPARISON STUDY 25 AUGUST 1989 The known value for gross alpha activity is 6.00 pCl/ filter with an expected laboratory precision 5.00 (1s,1 determination).

NCSU ENVIRONMENTAL LABORATORY RESULTS ALPHA Exper. Ang anal Normalized deviation Lab Bgt.1 M Res.3 SQma (R + SR) -Avernae farand-ava) (known)

CA 4.0 6.0 5.0 1.00. 0.237 5.00 -0.52 0.35 l STATISTICAL

SUMMARY

OF 119 PARTICIPANTS i

Statistic Resoondents Non outliers Mean 6.69 Grand Avg 6.51 Std. Dev. 2.510 1.563 Variance 6.302 2.442

% Coel, of Var.- 37.5 24.0

% deviation of mean from known value 11.5 8.52 l Norm. dev, of mean from known value 0.276 0.327 Median 6.33 6.33

% deviation of madian from known value 5.5 5.5 Norm. dev.of median from known value 0.133 0.213 9

l l

l 21

,I I

. I y i TABLE 7.ib 1370 s ACTIVITY AIR FILTER INTERCOMPARISON STUDY 25 AUGUST 1989 3 i

The known va!ue for Ceslum 137 activity is 10.00 pCl/ filter with an expected laboratory precision of 5.00 (1s,1 determination). I NCSU - ENVIRONMENTAL LABORATORY RESULTS  !

137 Cs I Exper. Rng anal Normalized deviation

. Lab bel _1 Res.2 BasJ Sigma. (R + S A) Avernoe forand aval(known)

CA 10.00 11.00 13.00 1.53 0.355 11.33 0.19 0.46 i

STATISTICAL

SUMMARY

OF 107 PARTICIPANTS i Statistic Roemndents Non. outliers Mean 12.19 Grand Avg 10.79 Std. Dev. 9.17 1.96 Variance 84.134-

% Coel, of Var. 3.831  !

75.2 18.1

% deviation of mean from known value 21.9 7.94 Norm, dev. of mean from known value ' O.239 0.406 Median 10,67 10.67

% deviation of median from known value 6.7 6.7 Norm, dev. of median from known value 0.073 0.341 i

i i

t I

TABLE 7.1c GROSS ALPHA ACTIVITY IN WATER INTERCOMPARISON STUDY -

22 SEPTEMBER 1989  ;

The known value for gross alpha activity is 4.00 pCl/ liter with an expected laboratory precision of -

l 5.00 (1s,1 determination).

NCSU - ENVIRONMENTAL LABORATORY RESULTS t GROSS ALPHA l- Exper. Ang anal- Normalized deviation 1,ab M M M Sglma (R + SR) Avernae (arand ava)(known) 04 4.0 6.0 6.0 1.15 0.237 5.33 0.33 - 0.46 STATISTICAL

SUMMARY

OF 1851 PARTICIPANTS Statistic Resoondents . Non out!iers Mean 4.89 Grand Avg 4.38 Std. Dev. 4.785 1.816 Variance 22.898 3.297 1

% Coef of Var. 97.8 41.4

% deviation of mean from known value 22.25 9.62 Norm, dev, of mean from known value 0.187 0.212 Median 4.00: 4.00 l

% deviation of median from known value 0.00 0.00 Norm, dev. of median from known value 0.00 0.00 l-l i

I 23

b k

TABLE 7.1d GROSS BETA ACTIVITYIN WATER INTERCOMPARISON STUDY-22 SEPTEMBER 1989 The known value for gross beta activity is 6.00 pCVliter with an expected laboratory precision of 5.00 (1s,1 determination).

i NCSU ENVIRONMENTAL LABORATORY RESULTS L GROSS BETA i

Exper. Ang anal Normalized deviation Lab- BgL.1 Bgt,2 Hgt) Sigma (R + SR) Avernae (arand ava)(known)-

CA 7.0 6.0 9.0 1.53 0.355 7.33 0.22 0.46 ,

STATISTICAL

SUMMARY

OF 153 PARTICIPANTS 3

Statistic Resoondents Non outliers ' }

l Mean 8.83 Grand Avg 6.70 Std. Dev. 13.05 1.83 Variance 170.24 3.35

% Coef of Var. 147.7 - 27.3 -

% deviation of mean from known value 47.17 :11.60 Norm, dev. of mean from known value 0.217 0.381 Median 6.67 6.67

% deviation of median from known value 11.17 11.17 Norm dev. of median from known value 0.051 0.364 l

i ,

24 L

i

s .

TABLE 7.1e TRITIUM IN WATER INTERCOMPARISON STUDY 20 OCTOBER 1989 The known value for tritium activity is 3496.00 pCVliter with an expected laboratory pre ision of 364.00 (1s,1 determination),

o.

NOSU ENVIRONMENTAL LABORATORY RESULTS .

3g Exper. Rng anal Normalized deviation Lit. He1.1 Bat.2 Res.3 SQma (R + SR) Averaae (arand.ava)(known) m 3483.0 3758.0 .4022.0 269.52 0.877 3754.33 1.35 1.23 STATISTICAL

SUMMARY

OF 126 PARTICIPANTS Statistic Resoondents Non. outliers Mean 3595.88 Grand Avg 3471.07 Std. Dev. 1335.862 369.076 Variance 1784526.750 136216.953

!  % Coef, of Var. .37.1 10.6 *

% deviation of mean from known value. 2.86- 0.71 Norm, dev. of mean from known value 0.075 0.068 Median 3465.00 -3463.33

% deviation of median from known value 0.89 0.93 Norm dev. of median from known value 0.023 -0.089 l'

1 25 l

1 l

.l

=. -

l l

l-e l l t

TABLE 7.1f GROSS ALPHA ACTIVITY AIR FILTER INTERCOMPARISON STUDY -

30 MARCH 1990 The known value for gross alpha activity is 5.0 pCl/ filter with an expected laboratory precision of 5.0 (1s,1 determination).

NCSU ENVIRONMENTAL LABORATORY RESULTS ALPHA Exper, Rng anal Normalized deviation Lab BfuL1 Res. 2 Battl Sigma (R + SR) Averane forand-ava)(known)

CA 5.0 5.0 6.0 0.58 0.118- 5.33 - 0.32 0.12 STATISTICAL

SUMMARY

OF 185 PARTICIPANTS Statistical Resoondents Non-outliers Mean 6.35. Grand Avg 6.25-Std. Dev. 1.66 1.31 Variance 2.75 1,72 l  % Coel,of Var. 26.14 20.94

% deviation of mean froin known value '26.94 25.09 Norm.dev, of mean from known value 0.81 0.96 Median 6.00 6.00

% deviation of median from known value 20.00 20.00 Norm, dev. of median from known value 0.60 0.76 l

26

.~. . _ _ ..

l .

j N

1

- TABLE 7.1g GROSS BETA ACTIVITY AIR FILTER - INTERCOMPARISON STUDY - l 30 MARCH 1990

)

The known value for gross beta activity is 31.0 pCVfilter with an expected laboratory precision of 5.0 (1s,1 determination). -

NCSU - ENVIRONMENTAL LABORATORY RESULTS Bftla Exper.- Rng anal Normalized deviation 1.ab BELL Res.2 BBL 3 310ma (R + SR) Avernos (orand.svoifknown)

CA 30.0 32.0 32.0 1.15 0.236 31.33 0.30 0.12 l

1 STATISTICAL

SUMMARY

OF 185 PARTICIPANTS l l

Statistic Resocndents Non. outliers Mean 32.56 Grand Avg 32.19 Std. Dev. 7.63 3.68 Variance . 58.15 13.54

% Coef.of Var. 23.42 11.43

% deviation of mean from known value 5.03 3.85 Norm dev. of mean from known value 0.20 0.32 Median 32.33' 32.33.

% deviation of median from known value 4.30 4.30 Norm.dev. of median from known value 0.17- 0.36 l

27 l

L _ _

5 TABLE 7.1h GROSS ALPHA ACTIVITYIN WATER INTERCOMPARISON STUDY-11 MAY 1990 The known value for gross alpha activity is 22.0 pCl/ liter with an expected laboratory precision of 6.0 (1s,1 determination).

NCSU ENVIRONMENTAL LABORATORY RESULTS GROSS ALPHA  :

Exper. Rng anal. Normalized deviation i Lah. - Res.1 Res. 2 BEL.3 SQma (R + SR) - Avernas (orand.ava)(known) i- 04 19.0 22.0 23.0 2.08 0.3 94 21.33 1.26 0.19 STATISTICAL

SUMMARY

OF 230 PARTICIPANTS Statistic ' Rennondents Non. outliers Mean 18.56- Grand Avg. 16.97 Std. Dev. 15.31 6.11 l_

Variance 234.29 37.35 l  % CoeI, of Var. 82.46

' 36.01 ~

% deviation of mean from known value -15.63 22.84 Norm, dev. of mean from known value 0.22- 0.82 Median 18.00 17.67

% deviation of median from known value 18.18 19.70 Norm.dev, of median from known value 0.26 0.71 i

28

s '

TABLE 7.11 GROSS BETA ACTMTY IN WATER - ItCERCOMPARISON STUDY - l 11 MAY 1990 - l The known value for gross beta activity is 15.0 pCVliter with an expected laboratory precision of 5.0 '

(1s,1 determlnation).

1 NCSU ENVIRONMENTAL LABORATORY RESULTS GROSS BETA Exper. Rng anal Normalized deviation Lab. Ecs 1 Res.2 Bes 3 Sigma (R + SR) Averace (orand.avo)(known)

Q4 14.0 -16.0 17.0 1.53 0.354 15.67 0.17 0.23 STATISTICAL

SUMMARY

OF 230 PARTICIPANTS Statistic - Resnondents ' Non. outliers Mean 17.98 Grand Avg 16.16 4 Std. Dev. 10.90 3.85 Variance 118.83 14.81

% CoeI, of 'tbr. 60.61 23.82

% deviation of mean from known value 19.89 7.72 Norm, dev.of mean from known value 0.27 0.30 Median 16.33 16.33

% deviation of rnedian from known value 8.89 8.89 Norm, dev of median from known value 0.12 0.35 1

29 l

l

i l

8. CONCLUSIONS The data obtained during this period do not show any fission product activities other than possibly very low levels of Cs 137 and Ce 144 which can be attributed to residual fallout and are well below the l

Alert Levels and Regulatory Umits in Table 2.3. The observed environmental radioactivity is due  !

primarily to radon progeny, primordial radionuclides (e.g., K 40) and radionuclidos (e.g., Be 7) I which originate in the upper atmosphere as the result of cosmic ray interactions. These facts justify  ;

the conclusion that the PULSTAR Reactor facility continues to operate in a manner which does not adversely affect the university environment.

9.' ACKNOWLEDGMENTS Great appreciation is expressed to Mr. Jack Weavtr of '.he Department of Nuclear Engineering for the several months of counting assistance which he graciously provided.l Additionally, the graphs in this report would not have been possibia without the assistance of Mr. Worth Bowman of the Radiation -

Protection Office. Finally the excellent appearance of the report is due entirely to the dedicated efforts of Mrs. Ginger Davis, i

1 30

+ s a

\

APPENDIX 1 The vertical columns in Tables 7 are identified as columns 18 from left to right. ,

Column 1: Laboratory identif, cation code (e.g., OA).

Columns 2,3,4: Laboratory results given in tripucate. .

Column 5: Standard deviation (1s) of the experimental resu!!s.

Column 6: Normalized range value in *rnean range + standard error of the rango".

Column 7: Average value of the triplicate analysis.

Column 8: Normalized deviation from the grand average value of aillaboratories expror, sed in omunits.

Column 9: Normalized deviation from the known value expressed in mo units.

The following example calculation gives a set of data, the mean value, the experimentai sy..s, aree range. These statistics provide measures of the central tendency and dispersion of the data.

The normalized range is computed by first finding mean range, R, the controllimit, CL, and the standard error of the range, oR. The normallzed range measures the dispersion of the data (precision) in such a form that control charts may be used. Control charts allow one to readily compare past analytical performance with present performance. In the example, the normalized range equals 0.3 which is lots thr.n 3 which is the upper control level. The precision of the results is acceptable.

The normaliz9d deviation is calculated by computing the deviation and the standard error of the mean, o m . The normalized deviation allows one to measure central tendency (accuracy) readily through tho e ., vf control charts. Trends in analytical accuracy can be determined in this manner. For this i

example, the normalized deviation is 0.7 which falls between 42 and 2 which are the upper and lower warning levels. The accuracy of the data ls accepthble.

Finally, the experimental error of all laboratories, the grand average, ur4d the notmalized deviation from the grand average are calculated in order to ascertain the performance of all the saboratories t as a group. Any bias in methodology or instrumentation may be indicated by these results.

t l

l l

31

i

,,' s, f

I j

EXAMPLE CALCULATION $

Caperimental cata:

Known value = p = 3273 pC1 3H/11ter urine on Septerrcer 24, 1974 j Expected laboratory precision = a e 357 pCi/ liter Laboratory sample Result 9 xi 3060 pct /)tter 0 x2 3060 pCi/ liter  ;

0 x3 3240 pCf/ liter i

~

Mean = x >

(

Y i

I xj tal 9360 I . . e 3120 pC1/ liter

' N 3 where N

• nun .t of results

• 3 i Experimental sigma = s ,

fh \g I I- I t N (1-1 As/

I (ag)2 .

11 N s =

N-1 2 2 2 (3060 + 3060 + 3240j2 (3060) + (3060) + (3240) -

J s =

2 s = 103.9 pC1/11ter j Range a r r a j maximum result - minimum result l r

• l3240-3060l

• 180 pCi/ liter 32

,.>e .

Range Analysis (RhG ANLY)=

Mean range = I K= d;a enere d2**

• 1.693 for N e 3

= (1.693) (357)

N= 604.4 pCi/ liter Control 1!:.it a CL CL = % + 3ag

= DY 4

where D 4 "

= 2.575 for N = 3

= (2.575) (604.4)

CL = 1556 pct / liter Standard error of the range = ag aR (R + 37R

• II i 3

= (04 1 - 1)  ; 3 l

= (15$6 - 604.4)  ; 3 og = 317.2 pCi/ liter Let range a r = wi + xaR = 180 pCi/ liter Define normalized range = w+x for r > K, w = 1 then r a wi + xag = R + xag r-I '

or x =

1. R r-I therefore w+x = 1+x = 1+

aR

• Rosenstein, M., and A. S. Goldin, " Statistical Techniques for Quality Contrci of Environmental Radioassay,' A0CS Report Stat-l', U.S. Departr+nt of healtn Education and Welfare, PHS, NoFember 1964.

"From table " factors for Computing Control Limits," Handbook of Tables f or Probability _ and Statistics, 2nd Edition. The Chemical Rubber Co., Cle eland, Dhlo, 1968, p. 454.

33

- . ~ . .

e l

i t

for r ,c, R , a = 0 f then r a 51 + x aR * *I r

or w =~ l X

r i theref -e

• t a w+0 -

X 4

si, t r < I, (180 < 604.4) 4 180 w+x = l 4

604.4  !

w+x = 0.30 a hD Normalized deviation of the mean from the known value -

= 0

, Deviation of mean from the known value ,

D = i-p

= 3120 - 3213 0 = - 153 pct / liter

=

Standard error of the mean 'm Om A ,

357 l N

'm

• 206.1 pct / liter D

ND = -

Um

. - 153 76CI ND = - 0.7 Control limit = CL CL = (p 30m) l Warning Limit = WL WL = (p

• 2g)

I 34 i

4 e

• e O

Experiaiental sign.a (all laboratories) =

st fh \2 l

(at)g -

\1 = s xi)

I is!  ?.

st

) N- 1 (49345)?

162639133 15 14 Grand average = GA N

I xj ist GA .*

h 49345 15 CA = 3293 pCi/ liter Normalized deviation from the grand average a hD' Deviation of the n.ean from the grano average = D' D' = I -

CA

= 3120 - 3290 0'= - 170 pCi/ liter D'

ND' = -

Om

- 170 l 206.I 1

ND' = - 0.8 35