ML20072P254

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Environ Radiation Surveillance Rept for Period Jul 1993 - June 1994
ML20072P254
Person / Time
Site: North Carolina State University
Issue date: 06/30/1994
From: Elayadi A, Harris R
North Carolina State University, RALEIGH, NC
To:
Shared Package
ML20072P229 List:
References
NUDOCS 9409070152
Download: ML20072P254 (33)
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Text

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NORTH CAROLINA STATE UNIVERSITY DEPARTMENT OF ENVIRONMENTAL HEALTH & SAFETY l

RADIATION PROTECTION OFFICE ENVIRONMENTAL RADIATION SURVEILLANCE REPORT FOR THE PERIOD JULY 1,1993 - JUNE 30,1994 PREPARED BY RALTON J. HARRIS  !

AND l

ANISSA N. ELAYADI l Attachment A

?$8'58$8E73$8SS$97 a ena

TABLE OF CONTENTS PAGEto.

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1. INTRODUCTION 1
2. AIR MONITORING 2 Table 2.1 Location of Air Monitoring Stations 2 Figures 2a-2e Airborne Gross Beta Activities 3-7 l Table 2.2 Aerially Transported Gamma Activity 8-9 Table 2.3 Regulatory Limits, Alert Levels and Background Levels for Airborne Radioactivity 10 l
3. MILK Table 3.1 11
4. SURFACE WATER Table 4.1 Gross Alpha and Beta Activity in Surface Water 12 Table 4.2 LLD Values for Gamma Emitters in Surface Water 13
5. VEGETATION Table 5.1 Gross Beta Activity in Campus Vegetation 14 Table 5.2 LLD Values for Gamma Emitters in Vegetation 15
6. THERMOLUMINESCENT DOSIMETERS 16 Table 6.1 Environmental TLD Exposures 17
7. QUALITY CONTROL INTERCOMPARISON PROGRAM 18 1

Tables 7.1a - 7.1g 19 - 25

8. CONCLUSIONS 26
9. ACKNOWLEDGMENTS 26 APPENDIX 1 27 l

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1. INTRODUCTION The Environmental Radiation Surveillance Program exists to provide routine measurements of the university environment surrounding the PULSTAR Reactor. The specific objectives of this program include:
1) Providing information that assesses the adequacy of the protection of the university community and the public-at-large;
2) Meeting requirements of regulatory agencies;
3) Verifying radionuclide containment in the reactor facility;
4) Meeting legal liability obligations; and
5) Providing public assurance and acceptance.

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2. AIR MONITORING (TABLES 2.1,2.2, AND 2.3; FIGURES 2a THROUGH 2e)

Figures 2a through 2e show bar graphs of gross beta activity (fCi/ cubic meter vs, week number).

The highest gross beta activity observed was 53.0 fCi m-3 at the Broughton station during the week of d8/10/93. The annual campus average was 17.4 fCi m-3. Instances of missing data for a monitor station are due to pump and electric motor malfunctions.

Table 2.2 lists LLD values for several gamma emitters which would be indicative of fission product activity. No camma activity due to any of these radionuclides was detected.

Table 2.3 lists regulatory limits, alert levels, and average background levels for airborne radioactivity.

TABLE 2.1 LOCATION OF AIR MONITORING STATIONS SITE DIRECTION 1 DISTANCE 2 ELEVATION 3 (meters) (meters)

BROUGHTON SOUTHWEST 125 -17 DAVID CLARK LABS WEST 500 -18 LIBRARY NORTHWEST 192 +11 RIDDICK SOLTTHEAST 99 -14 WITHERS NORTHEAST 82 -6 1 DIRECTION-DIRECTION FROM REACTOR STACK 2 DISTANCE-DISTANCE FROM REACTOR STACK 3 ELEVATION ELEVATION RELATIVE TO THE TOP OF THE REACTOR STACK I i

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WEEK NUMBER FROM JUNE 29, 1943 TitROITC11 JITNF 23, 1994

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i FICURE 2 b AIRBORNE GROSS BETA ACTIVITY REGl'LATORY LIMIT =1000 fCi/C11BIC M N. C. STATE UNIVERSITY CMTPUS ,\LERT IR fCi/ CUBIC M BROUGHTON 5 5 --

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TABLE 2.2 TABLE 2.2 AERIALLY TRANSPORTED GAMMA ACTIVITY (fCi m E-3)

NUCUDES

_..___1____...__ . _ , .

4_

SAMPLING PERIOD Co-57 Co-60 Nb-95__ Zr-95_ ._ .R u- 10 3 R u-10 6 C s-137 Ce-141 C e-14 4 1993 0.62 0.39 2.86 0.32 0.53 1.59 06/29 - 07/06 0.19 0.35 0.39 0.32 0.59 0.35 2.94 0.32 0.46 1.66 07/06 - 07/13 0.19 0.39 0.25 0.42 0.24 2.09 0.24 0.29 1.17 07/13 - 07/20 0.13 0.38 0.24 0.38 0.23 2.21 0.24 0.29 1.35 07/20 - 07/28 0.17 0.29 0.29 0.52 0.45 0.68 0.39 3.62 0.42 0.52 2.22 07/28 - 08/03 0.3 0.49 0.31 2.41 0.29 0.4 1.45 08/03 - 08/10 0.18 0.32 0.2 0.34 0.2 1.68 0.19 0.26 1.07 08/10 - 08/19 0.14 0.24 0.55 0.5 0.68 0.43 3.83 0.47 ._ 0.57 _}_ 2.49 08/19 - 08/24 0.33 _

0.35 0.32 0.42 0.29 2.48 0.27 0.37 1.64 08/24 - 08/31 0.21 0.26 0.23 0.4 0.23 1.84 0.21 0.3 1.09 08/31 - 09/07 0.14 0.19 0.2 0.33 0.2 1.54 0.17 0.27 0.96 09/07 - 09/15 0.13 0.28 0.46 0.27 2.33 0.24 0.35 1.35 09/15 - 09/21 0.17 0.32 0.34 0.21 1.94 0.21 0.27 1.09 09/21 - 09/29 0.14 0.24 0.21 0.58 0.22 0.67 0.2 1.81 0.46 0.55 2.45 09/29 - 10/05 0.32 0.32 0.26 0.39 0.25 2.16 0.24 0.32 1.32 10/05 - 10/12 0.17 e 0.3 0.54 0.32 2.36 0.26 0.49 1.49 10/12 - 10/18 0.19 0.27 0.22 0.16 0.28 0.17 1.61 0.16 0.22 0.94 i 10/18 - 10/27 0.12 0.47 0.35- 0.68 0.38 3.29 0.37 0.51 2.01 10/27 - 11/03 0.25 0.33 0.26 0.48 0.28 2.47 0.27 0.37 1.53 11/03 - 11/10 0.19 0.51 0.44 -0.75 0.42 4.08 0.45 0.6 2.37 11/10 - 11/16 0.31 0.28 0.48 0.29 2.21 0.24 0.42 1.44 11/16 - 11/23 0.18 0.35 0.21 0.16 0.28 0.17 1.44 0.17 0.24 0.92 11/23 - 11/30 0.12 0.28 0.24 0.39 0.23 2.24 0.23 0.32 1.34 11/30 - 12/07 0.17 0.29 0.49 0.37 1.91 0.19 0.6 1.11 12/07 - 12/16 0.14 0.23 0.28 0.48 0.35 1.8 0.15 0.57 1.08 12/16 - 12/23 0.11 0.22 0.37 0.4 0.64 0.46 2.79 0.31 0.65 1.67 12/23 - 12/30 0.22 ALL DATA IN TABLE 2. 2 ARE LLD VALUES.

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TABLE 2.2 1993-1994 ,

TABLE 2.2 AERIALLY TRANSPORTED GAMMA ACTIVITY (fCi m E-3) I, i

NUCLIDES SAMPLING PERIOC Co-57 Co-60 Nb-95 Zr-95 Ru-103 Ru-106 C s-137 C e - 141 Ce-144 1994 ,

0.36 0.36 0.62 0.41 2.69 0.32 0.63 1.71 12/30 - 01/04 0.21 0.2 0.37 0.3 0.52 0.38 2.71 0.29 0.53 1.58 01/04 - 01/11 0.18 0.32 0.27 0.46 0.29 2.26 0.27 0.39 1.44 01/11 - 01/18 01/18 - 01/;25 0.24 0.44 0.34 0.6 0.36 3.03 0.33 0.51 1.87 0.18 0.28 0.28 0.46 0.28 2.38 0.28 0.37 1.42 01/25 - 02/01 0.24 0.21 0.34 0.22 1.74 0.2 0.3 1.16 02/01 - 02/10 0.15 02/10 - 02/15 0.24 0.47 0.36 0.68 0.37 3.08 0.37 0.47 2 0.13 0.24 0.24 0.42 0.25 1.96 0.19 0.35 1.07 02/15 - 02125 .

0.32 0.61 0.57 0.88 0.54 4.55 0.47 0.77 q 2.48 02/25 - 03/01 0.32 0.28 0.47 0.26 2.53 0.28 0.33 1.46 03/01 - 03/08 0.18 03/08 - 03/15 0.2 0.34 0.29 0.48 0.25 2.75 0.28 0.37 1.51 0.22 0.36 0.33 0.55 0.3 3.11 0.35 0.42 1.74 03/15 - 03/22

,; 03/22 - 03/30 0.2 0.32 0.35 0.65 0.38 2.96 0.31 __0.61 _ }_._ 1.53 0.31 0.57 0.69 1.1 0.81 4.3 0.43 1.3 2.4 j 03/30 - 04/05 0.19 0.32 0.4 0.65 0.47 2.56 0.29 0.75 1.53 04/05 - 04/12

  • 0.3 0.51 0.52 0.96 0.63 4.05 0.44 0.96 2.34 04/12 - 04/19 04/19 - 04/27 0.26 0.37 0.4 0.71 0.42 3.3 0.36 0.69 2.02 04/27 - 05/03 0.32 0.51 0.53 0.85 0.52 4.34 0.48 _

0.77 2.56 0.25 0.43 0.38 0.62 0.37 3.21 0.4 0.48 1.96 05/03 - 05/10 0.27 0.45 0.53 0.92 0.63 3.69 0.41 0.1 2.19 05/10 - 05/17 0.21 0.37 0.31 0.56 0.29 2.73 0.31 0.38 1.56 05/17 - 05/24 0.22 0.38 0.35 0.55 0.3 3.08 0.33 0.45 1.83 05/24 - 05/31 0.37 0.29 0.49 0.3 2.81 0.32 0.39 1.7 05/31 - 06/07 0.21 0.2 0.34 0.32 0.55 0.28 2.56 0.28 0.45 1.59 06/07 - 06/14 0.27 0.23 0.44 0.23 2.1 0.25 0.33 1.3 06/14 - 06/21 0.16 06/21 - 06/28 0.16 0.26 0.24 0.41 0.23 1.99 0.22 0.33 1.21 ALL DATA IN TABLE 2.2 ARE LLD VALUES.

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I TABLE 2.3 REGULATORY LIMITS, ALERT LEVELS, AND BACKGROUND LEVELS FOR AIRBORNE RADIOACTIVITY (fCi m-3)

REGULATORY ALERT AVERAGE N.C. l LEVEL BACKGROUND LEVEL EUCLIDE LIMIT f 20 10 4 GROSSALPHA l GROSSBETA 1000 500 100 l Cs-137 5 x 105 10 2 l

Ce-144 2 x 105 10C 0 Ru-106 2 x 105 30 0 1-131 1 x 105 10 0

Reference:

Environmental Radiation Surveillance Report 1986-88, State of N.C.

Radiation Protection Section l

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3. MILK (TABLE 3.1) l l

Milk samples are collected each month from the Campus Creamory and the Lake Wheeler Road Dairy.

Previously, samples were obtained from the Ran:lleigh Dairy Farm but it is no longer operational.

The FDA's Preventive Action Guide (PAG) for 1-131 is 1.5 X 104 pCi/ liter for infants. All analyses during this 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.

TABLE 3.1 1-131 IN COWS' MILK (pCi liter-1 2 c) LLD - 3 pCi liter-1 pCi liter -1 D6]E CAMPUS CREAMERY LAKE WHEELER JULY 1993 s 3.0 s3.0 AUGUST 1993 s 3.0 s 3.0 SEPTEMBER 1993 s 3.0 s 3.0 OCTOBER 1993 s 3.0 s 3.0 NOVEMBER 1993 s 3.0 s 3.0 DECEMBER 1993 s 3.0 s 3.0 JANUARY 1994 s 3.0 s 3.0 FEBRUARY 1994 s 3.0 s 3.0 MARCH 1994 s 3.0 s 3.0 APRIL 1994 s 3.0 s 3.0 MAY 1994 s 3.0 s 3.0 JUNE 1994 s 3.0 s 3.0 11

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4. SURFACE WATER (TABLES 4.1 AND 4.2)

~

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

- 0.4 pCiliter1 and - 0.4 pCiliter1, respectively. For gross alpha activity the Alert Levelis 5 pCi liter 1 and the Regulatory Limit is 15 pCiliter1. For gross beta activity the Alert Levelis 12.5 pCi literl and the Regulatory Limit is 50 pCi liter d Samples with gross alpha or beta activities exceeding these Alert Levels would require gamma analysis to identify the radionuclides present. The LLD values in Table 4.2 are for the second quarter of 1994.

TABLE 4.1 GROSS ALPHA AND BETA ACTIVITY IN SURFACE WATER (pCiliter1 2 c)

  • LLD a - 0.4 pCi liter 1 LLDp - 0.4 pCi liter-1 oCi liter 1 GR33S GFQE DAIE LOCATION ALPHA BEM THIRD OUARTER 1993 ON < 0.4 0.8 0.3 OFF < 0.4 < 0.4 FOURTH OUARTER 1993 ON < 0.6 < 0.5 OFF < 0.6 < 0.5 FIRST QUARTER 1994 ON < 0.3 1.4 0.4 OFF < 0.3 1.3 0.3 SECOND OUARTER 1994 ON < 0.3 1.4 0.4 OFF < 0.3 1.3 2 0.4
  • LLD VALUES ARE DETERMINED OUARTERLY 12

TABLE 4.2 LOWER LIMITS OF DETECTION FOR SEVERAL GAMMA EMITTERS IN l

SURFACE WATER FROM NCSU ERSL ANALYSIS l

NUCL!DE LLD (oCi liter 1)*

Co-60 0.4 Zn-65 0.7 Cs-137 0.3 Cs-134 0.4 Sr-85 0.4 Ru-103 0.3 Ru-106 3.0 Nb-95 0.4 Zr-95 0.5

  • LLD VALUES ARE FOR THE 2ND OUARTER OF 1994 13

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5. VEGETATION (TABLE 5.1 and 5.2)

Table 5.1 gives gross beta activities for grass samples collected on the NCSU Campus. The reported activities are all below the Alert Level of 20 pCi gram -1. Table 5.2 lists LLD values for several gamma emitters. No gamma activity due to any of these radionuclides has been observed in campus vegetation. The beta and gamma activities are reported as pCi per gram of green vegetation.

TABLE 5.1 GROSS BETA ACTIVITY IN CAMPUS VEGETATION *LLD ~ 0.5 pCi g-1 SAMPLE DATE SAMPLE LOCATION (oCia-1 lgj DECEMBER 1993 NORTH CAMPUS 2.8 0.1 s DECEMBER 1993 SOUTH CAMPUS 2.7 0.1 DECEMBER 1993 EASTCAMPUS 2.7 0.1 DECEMBER 1993 WEST CAMPUS 4.4 0.2 APRIL 1994 NORTH CAMPUS 2.7 0.1 APRIL 1994 SOUTH CAMPUS 2.6 0.1 APRll 1994 EAST CAMPUS 2.8 0.1 APRIL 1994 WEST CAMPUS 2.7 0.1

  • LLD values are determined semiannually 1

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Table 5.2 LLD VALUES FOR GAMMA EMITTERS IN VEGETATION NUCLIDE LLD (oCi oram-1)*

Co-60 0.01 Zn-65 0.02 Cs-137 0.01 Cs-134 0.01 Sr85 0.01 Ru-103 0.01 Nb 95 0.01 Zr-95 0.02

  • LLD VALUES ARE FOR THE 2ND QUARTER OF 1994 i

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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 cjosimeters are CaSO4doped with dysprosium and have a manufacturer-stated sensitivity of 0.5 0.15 mR (90% C.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) sampling locations.

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.

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7. QUALITY CONTROL INTERCOMPARISON PROGRAM The Environmental Radiation Surveillance Laboratory of the Radiation Protection Office has participated in the U. S. EPA Environmental Laboratory Intercornparison Studies Program during this reporting period. The objective of this program is to provide laboratories performing environmental radiation measurements with unknowns to test their analytical techniques. The results of the intercomparison studies are given in Tables 7.1 a-g 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.

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. C TABLE 7.1a GROSS ALPHA ACTIVITY AIR FILTER -INTERCOMPARISON STUDY

- 27 AUGUST 1993 The known value for gross alpha activity is 19.0 pCi/ filter with an expected laboratory precision of 5.0 (1s,1 determination).

NCSU - ENVIRONMENTAL LABORATORY RESULTS ALPHA Exper. Rng anal Normalized deviation Lab Res.1 Res.2 Res. 3 Sigma (R + SR) Averaae (arand-ava) (known)

Q\ 17.0 19.0 18.0 1.00 0.236 18.00 -0.69 -0.35 STATISTICAL

SUMMARY

OF 204 PARTICIPANTS Statistic Resoondents Non-outliers Mean 20.35 Grand Avg 20.00 Std. Dev. 4.67 3.27 Variance 21.78 10.70

% Coef. of Var. 22.93 16.36

% deviation of mean from known value 7.13 5.24 Norm. dev. of mean from known value 0.29 0.30 Median 19.67 19.67

% deviation of median from known value 3.51 3.51 Norm. dev. of median from known value 0.14 0.20 19

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8 l TABLE 7.1 b GROSS BETA ACTIVITY AIR FILTER -INTERCOMPARISON STUDY -

27 AUGUST 1993 The known value for gross beta activity is 47.0 pCi/ filter with an expected laboratory precision of 5.0 (1s,1 determination).

NCSU - ENVIRONMENTAL LABORATORY RESULTS BETA Exper. Rng anal Normalized deviation Lab Res.1 BEL 2 Ros, 3 Siama (R + SR) Averace (arand-avaMknown)

CA 51.0 49.0 49.0 1.15 0.236 49.67 0.12 0.92 STATISTICAL

SUMMARY

OF 189 PARTICIPANTS Statistic Resoondents Non-outliers Mean 49.86 Grand Avg 49.32 Std. Dev. 7.82 4.62 Variance 61.22 21.38

% Coef. of Var. 15.69 9.37

% deviation of mean from known value 6.07 4.93 Norm.dev.of mean from known value 0.36 0.50 Median 49.00 49.00

% deviation of median from known value 4.26 4.26 Norm. dev. of median from known value 0.26 0.43 i

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I TABLE 7.1c 137Cs ACTIV!TY AIR FILTER INTERCOMPARISON STUDY-27 AUGUST 1993 I

The known value for Cesium-137 activity is 9.0 pCi/ filter with an expected laboratory precision  !'

of 5.0 (1s,1 determination).

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NCSU - ENVIRONMENTAL LABORATORY RESULTS l 127 Cs Exper. Rng anal Normalized deviation Lab Pas 1 Res 2 Res. ') Siama (R + SR) Averace farand-ava)(known)

O\ 10.00 10.00 10.00 0.00 0.000 10.00 0.00 0.35 STATISTICAL

SUMMARY

OF 189 PARTICIPANTS Statistic Resoondents Non-outliers Mean 10.36 Grand Avg 10.00 Std. Dev. 2.98 1.62 Variance 8.89 2.63

% Coef, of Var. 28.80 16.22

% deviation of mean from known value 15.07 11.16 Norm, dev. of mean from known value 0.45 0.62 j Median 10.00 10.00 1

% deviation of median from known value 11.11 11.11 Norm, dev. of median from known value 0.34 0.62 l

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TABLE 7.1d GROSS ALPHA ACTIVITY IN WATER-INTERCOMPARISON STUDY

-28 JANUARY 1994 The known value for gross alpha activity is 15.0 pCi/ liter with an expected laboratory precision of 5.0 (1s,1 determination).

NCSU - ENVIRONMENTAL LABORATORY RESULTS GROSS ALPHA Exper. Rng anal Normalized deviation Lab Res.1 Res.2 B.eL3 Sicma (R + SR) Averace (arand.ava)(known)

O\ 12.0 14.0 13.0 1.00 0.236 13.00 -0.26 -0.69 STATISTIC AL

SUMMARY

OF 253 PARTICIPANTS Statistic Resoondents Non-outliers Mean 14.38 Grand Avg 13.75 Std. Dev. 5.97 4.25 Variance 35.68 18.08

% Coef. of Var. 41.55 30.92

% deviation of mean from known value 4.15 - 8.32 Norm. dev. of mean from known value -0.10 -0.29 Median 13.00 13.00

% deviation of median from known value - 13.33 -13.33 Norm. dev. of median from known value - 0.33 - 0.47 22

E TABLE 7.1e GROSS BETA ACTIVITY IN WATER -INTERCOMPARISON STUDY

-28 JANUARY 1994 The known value for gross beta activity is 62.0 pCi/ liter with an expected laboratory precision of 10.0 (1s,1 determination).

NCSU - ENVIRONMENTAL LABORATORY RESULTS GROSS BETA Exper. Rng anal Normalized deviation Lab Res.1 Res.2 Res. 3 Sigma (R + SR) Averaae (crand-ava)(known)

CA 69.0 70.0 71.0 1.00 0.118 70.0 2.40 1.39 STATISTICAL

SUMMARY

OF 253 PARTICIPANTS Statistic Resoondents Non-outliers Mean 56.86 Grand Avg 56.14 1 Std. Dev. 15.85 14.15 Variance 251.07 200.24

% Coef. of Var. 27.87 25.21

% deviation of mean from known value - 8.29 -9.45 Norm. dev. of mean from known value -0.32 -0.41 Median 57.67 57.67

% deviation of median from known value -6.99 -6.99 Norm. dev. of median from known value -0.27 -0.31 23

,- s' I TABLE 7.1f TRITIUM IN WATER - INTERCOMPARISON STUDY - 5 NOVEMBER 1993 The known value for tritium activity is 7398.0 pCi/ liter with an expected laboratory precision of 740.0 (1s,1 determination).

NCSU - ENVIRONMENTAL LABORATORY RESULTS 311 Exper. Rng anal Normalized deviation Lab Res.1 Res,2 Res,3 Sigma (R + SR) Averaae (crand-ava)(known)

CA 5018.0 5441.0 4652.0 394.84 0.630 5037.00 -5.10 -5.53 STATISTIC AL

SUMMARY

OF 220 PARTICIPANTS Statistic Resoondents Non-outliers Mean 7017.15 Grand Avg 7215.65 Std. Dev. 1320.54 574.68 Variance 1743826.64 330256.18

% Coef. of Var. 18.82 7.96

% deviation of mean from known value -5.15 -2.46 Norm. dev. of mean from known value - 0.29 - 0.32 Median 7209.00 7259.50

% deviation of median from known value - 2.55 -1.87 Norm. dev. of median from known value -0.14 -0.24 i

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E TABLE 7.1g TRITIUM IN WATER -INTERCOMPARISON STUDY - 4 MARCH 1994 The known value for tritium activity is 4936.0 pCi/ liter with an expected laboratory precision of 494.0 (1s,1 determination).

NCSU - ENVIRONMENTAL LABORATORY RESULTS 3H Exper. Rng anal Normalized deviation Lab Res.1 Res,2 BaL3 Siama (R + SR) Averaae (arand-avo)(known)

CA 5110.0 5097.0 5130.0 16.62 0.039 5112.33 0.94 0.62 STATISTIC AL

SUMMARY

OF 179 PARTICIPANTS Statistic Basoondents Non-outliers Mean 4923.89 Grand Avg 4844.97 Std. Dev. 1142.70 477.67 Variance 1305770,15 228168.29

% Coef. of Var. 23.21 9.86

% deviation of mean from known value -0.25 -1.84 Norm dev, of mean from known value - 0.01 -0.19 Median 4823.33 4819.00

% deviation of median from known value -2.28 -2.37 Norm. dev. of median from known value - 0.01 -0.24 25

8. CONCLUSIONS The data obtained during this period do not show any fission product activities. The observed environmental radioactivity is due primarily to radon progeny, primordial radionuclides (e.g.,

K-40) and those radionuclides (e.g.. Be-7) 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 safely and does not release fission product materials into the environment.

9. ACKNOWLEDGMENTS This office is greatly indebted to Mr. Bill Crocker and Mr. Dwight Dickens for their untiring efforts in collecting the environmental samples. Great appreciation is also expressed to Mr. Thomas Brackin for his work in repairing the air samplers.

The graphs in this report are available due to the assistance of Mr. Worth Bowman, and the entire arrangement and typing are due to the excellent efforts of Mrs. Ginger bavis and Miss Anissa Elayadi.

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4 APPENDIX 1 The vertical columns in Tables 7 are identified as columns 1-8 from left to right.

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

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

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

Column 6: Normalized range value in "mean range + standard error of the range".

Column 7: Average value of the triplicate analysis.

Column 8: Normalized deviation from the grand average value of alllaboratories expressed in omunits. .

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

The following example calculation gives a set of data, the mean value, the experimental sigma, and the 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 control limit, CL, and the standard error of the range, cR. The normalized 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 less than 3 which is the upper control level. The precision of the results is acceptable.

The normalized 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 the use of control charts. Trends in analytical accuracy can be determined in this manner. For this example, the normalized deviation is -0.7 which falls between +2 and -2 which are the upper and lower warning levels. The accuracy of the data is acceptable.

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

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C.

EXAMPLE CALCULATIONS Experimental data:

Known value = p = 3273 pCi 3H/11ter urine on September 24, 1974 )

.' Expected laboratory precision = o = 357 pCi/ liter l Laboratory _ Sample Re sul t D x1 3060 pCi/ liter D x2 3060 pCi/ liter D x3 3240 pCi/ liter Mean = i N

I xi i=1 9360 i = = = 3120 pCi/ liter N 3 where N = number of results = 3 Experimental sigma = s N

I xj N i-1 I (xj)2 -

i=1 N s =

N-1 2 2 2 (3060 + 3060 + 3240)2 (3060) + (3060) + (3240) - 3 s =

2 s = 103.9 pCi/ liter Range = r r = l maximum result - minimum result l r = } 3240 - 3060)

= 180 pCi/ liter 28

i 4: i i

  • . i l

i 1

1 Range Analysis (ENG ANLY)=  !

Mean range = R Y= de 2 where d2 ** = 1.693 for N = 3  !

= (1.693) (357)

R = 604.4 pCi/ liter Control limit = CL l

=

CL 7 + 3eR  !

= D7 4

where D4 ** = 2.575 for N = 3

= (2.575) (604.4)

CL = 1556 pCi/ liter Standard error of the range =

eR eR = (R + 3cp - R) e 3

= (D4 R - Y) e 3

(1556 - 604.4) t 3 og = 317.2 pCi/ liter Let range = r = wY + xeg = 180 pCi/ liter Define normalized range = w+x for r > R, w = 1 then r = wI + xeg

Y + xeR r-E or x =

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

UR

  • Rosenstein, M., and A. S. Goldin, " Statistical Techniques for Quality Control of Environmental Radicassay," AOCS Recert Stat-1, U.S. Department of Health Education and Welfare, PHS, Novemoer 19o4
    • From table " Factors for Computing Control Limits," Handbook of Tables for Probability and Statistics, 2nd Edition, The Chemical Ruocer Co., Cleveland, Oni o , 1966, p . 454.

29

1

. b d for r<R, x = 0 then r a JR + x ag = WR r

or w = - ^

- R r

therefore w+x = w+0 --

R since r < Y, (180 < 604.4) 180 w+x =

604.4 w+x = 0.30

= NO Normalized deviation of the mean from the known value

= 0 Ceviation of mean from the known value D = x-p

= 3120 - 3273 D = - 153 pCi/ liter Standard error of the mean = om

=

a g,

/"II 357

=

/3 em = 206.1 pCi/ liter D

ND = --

Um

= - 153 206.1 ND = - 0.7 Control limit = CL CL = ( 30m)

Warning Limit = WL WL = (p 2cm) 30

'* Jt :

Experimental sigma (all laboratories) = st (See Figure 2)

[N h2 )

I xi N

I (xj)2 -

ki"1 / .

i=1 N

=

st N-1 (49345)2 162639133 15

=

14 st = 149 pCi/ liter Grand average = GA N

I xi i=1 GA =

N 49345

=

15 GA = 3290 pCi/ liter

= ND' Normalized deviation from the grand average Deviation of the mean from the grand average = D' D' = x -

GA

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

ND' = --

7m

- 170

=

206.1 ND' = - 0.8 1

31 1

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