ML20082H821

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Environ Radiation Surveillance Rept for Jul 1990 to Jul 1991
ML20082H821
Person / Time
Site: North Carolina State University
Issue date: 07/31/1991
From: Harris R
North Carolina State University, RALEIGH, NC
To:
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ML20082H816 List:
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NUDOCS 9108260290
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RADIATION PROTECTION OFFICE i NORTH CAROLINA STATE UNIVERSITY ENVIRONMENTAL RADIATION SURVEILLANCE REPORT FOR THE PERIOD JULY 1990 JULY 1991 ATTACHMENT A RALTON J. HARRIS ENVIRONMENTAL HEALTH PHYSICIST l

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TABLE OF COtJTEldTS PAGEto

1. INTRODUCTIOt1 1
2. AIR moi 41TORif4G 3 Table 2.1 Location of Air Monitoring Stations 3 Figures 2a 20 Airborno Gross Deta Activitios 4  ;

Table 2.2 Aerially Transported Gamma Activity 0  :

Table 2.3 Regulatory Limits, Aler1 Levels and Background Levels (

i for Airborno Radioactivity 10 i

3. MILK {

Tablo 3.1 - -

12 [

4. SURFACE WATER '

Table 4.1 Gross Alpha and Beta Activity in Surface Water 13  !

Tablo 4.2 LLD Velves for Gamma Emitters in Surfaco Water 14  ;

5. VEGETATIOfJ  !

Tablo 5.1 Gross Beta Activity in Campus Vegetation 15 Table 5.2 LLD Values for Gamma Emitters in Vegetation 16

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6. THERMOLUMitJESCEl4T DOSIMETERS ,

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Tablo 6.1 Environmental TLD Exposures 18

7. QUALITY CONTROL llJTERCOMPARISOfJ PROGRAM 19 ,

Tables 7.la 7.1K 20  ;

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8. col 1CLUSIOtJS 31 t
9. ACKNOWLEDGMENTS 31 >

l APPENDIX 1 32

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4 During trus reporbng period free (5) new ais samphng sptems (Figures 1a & Ib) have been put into servico to replace the previous air monitoring stations. The current air camplers operate continuously 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> per day. Each sampler employ s one (1) 47 mm. diameter glass fiber futer and samples -1200 m 3of air per week. This air volumo is approxirriately 20 times greater than that achieved with the previous system, and has allowed the lower hmat of detection for gross beta activity to be reduced from - 10 ICI m'3 t o - 1 fCl m 3, Two other important features of the new samplers ar3 the volurne totahng capabihty and air temperature compensation. The voluma of air passing through the system is recorded by a digital test meter which is temperature compensated (referenced to 600 F) with an accuracy of 12% o<ur a range of 200 F to 1400F.

The Environmental radiation Survedlance Laboratory has continued to p %c pate in the EPA Environmental Laboratory Intercomparison Studies Program. The results of sesoral quahty control measurements are included in Section 7 of this report.

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l 2, AIR MONITORING (TABLES 2,1,2.2, /sND 2.3; FIGURES 2a THRU 2e)

Table 2.1 gives the locations of the campus air monitoring stations. Table 2.2 gives LLD va!ves for several gamma emitters which would be indicators of fission product releases. Table 2.3 gives a listing of Pegulatory Limits, Alert Levels, and average North Carolina background activity levels for those radionuclides for which data is available. Figures 2a thru 2e give gross beta activity levels for each monitor station.

During several weeks of this reporting period elevated levels of gross beta activity were actocted at all of the monitoring stations. At times, these activities vary by factors of 2 to 3 greatnr than the campus average of - 33101 m 3. Gamma spectral analysis cchfirms that this activity is due only to natural radioactivity (i.e., radon progeny). The highest gross beta activity observed was 100.8 fCi m 3 which is an order of magnitude below the regulatory limit of 1000 ICi m 3 T ABLE 2.1 LOCATION OF AIR MONITORING STATIONS SIIE EdBECTION1 DISTANCE 2 ELEVAT!ON3 (meters) (meters)

BROUGHTCN SOUTHWEST 125 17 DAVID CLARK LABS WEST 500 -18 LIBRARY NORTHWEST 192 e11 RIDDICK SOUTHEAST 99 14 WITHERS NORTHEAST 82 6 ,

1 DIRECTION D!RECTION FROM REACTOR STACK 2 DISTANCE DISTANCE FRGM REACTOR STACK 3 ELEVATION ELEVATION RELATIVE TO THE TOP OF THE REACTOR STACK 3

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FIGURE 2a AIRBORNE GROSS BETA ACTIVITY REGULATORY LIMIT =1000 fC1/ CUBIC M N. C. STATE UNIVERSITY CAMPUS ALERT LEVEL-500 fC1/ CUBIC m LLD-1 fC1/ CUBIC M I DAVID CLARK 120 i 100 i

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fCi per Cubic Meter 60 -

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1 3 5 7 9 11 131517192123 25272931 33353739414345474951 5355 Week Number From July 17,1990 Through July 16, 1991 I JULY 17 EECINS AT L'EEK #4 I

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I FIGURE 2b h.C TATE I' I VIP S A1, n' 5 f / CUB M LLD I fci/ CUBIC 11 i

BROUGHTCtJ 80 70 60 50

fCi per Cubic Meter 4 0 - - -- -

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r 1 3 5 7 9 1113151719 21 23 25 2729 31 3335373941 43 4547 49 51 53 55 l Week flumber From July 17,1990 Through July 16,1991 JULY 17 BEGINS AT 1?EET: #4

FIGURE 2c AIRBORNE GROSS BETA' ACTIVITY REGULATORY LIMIT =lOOO fCi/ CUBIC M -

N. C. STATE UNIVERSITY CAMPUS ALEFT m' 00 ICi/ CUBIC M RfDDICK 90 ---

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& fCi per Cubic Meter _ _

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d Ili HI 11am 1 3 5 7 9 11 13 15171921 2325 2729 31 33 3537 3941 43454749 51 53 55 Week number From July 17,1990 Throuch July 16. 1991 JULY 17 BEGINS AT 'n'EEk f 4

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TICURE 2d l

..l AIRBORNE CROSS BETA ACTIVITY REGULATORY LI?!IT=1000 fC1/ CUBIC !!  ;

N. C. STATE UNIVERSITY CA*1 PUS ALERT LEVEL =500 fci/ CUBIC 11  !

LLD-1 fCi/ CUBIC ?! I l

WITHERS l t l 70 60 4 - -

50 - - - -

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1 3 5 7 9 111315171921 2325 272931 33 35373941 43 454749 51 53 55 Week fJumber From July 17,1990 Through July 16.1991  !

JULY 17 EEGINS AT k'ED: f'4

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LLD-1 fCi/ CUBIC M i f

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TABLE 2.2 AERIALLY TRANSPORTED GAMMA ACTIVITY (LLD Values in fCi m' )

i NUCLIDES SAMPUNG PERIOD Co Co-60 Nb-95 Zr-95 Ru-103 Ru-106 Cs-137 C e- 1'41 C e- 144 1990 07/17-07/24 0.14 0.27 0.24 0.44 0.22 1.9 022 0.33 07/24-07/31 0.13 0.23 0.21 038 '020 1.1 1.5 0.18 028 07/31-08/07 0.16 0.29 0.24 0.40 021 1.0 08/07-08/14 0.15 031 2.1 022 032 12 0.23 0.37 0.19 2.1 024 0.29 08/14-08/21 0.22 0.36 0.35 0.52 028 1.1 1 2.9 032 037 1.7 08/21-08/28 0.16 0.28 0.29 0.48 0.26 23 08/28-09/04 0.18 0.35 026 036 13 0.29 0.48 0.26 -

2.6 028 036 09/04-09/11 0.16 0.30 025 0.44 023 1.4 23 026 033 12 09/11-09/18 0.28 0.50 0.40 0.77 038 3.6 09/18-09/25 024 0.45 0.51 ' 2.1 0.50 0.40 0.73 039 3.7 039 052 2.0 '

O9/25-10/02' O.17 0.32 025 0.47 0.25 23

  • 0.27 033 13 10/02-10/09 0.21 0.43 0.33 0.55 029 2.9 l

10/09-10/1'6 0.15 031 0.44 1.6 i 0.28 0.24 0.43 0.21 2.1 023 030 12 10/16-10/23 0.16 0.32 0.26 0.44 0.22 2.0 10/23-10/30 0.14- 024 0.29 12 0.26 0.22 0.42 0.19 1.9 10/30-11/06 0.17 022 026 1.1 -

0.32 0.28 0.47 025 23 027 031 1.3 11/06-11/13 --

POWER FAILURE - DATA LOST 11/13-11/20 0.19 0.37 0.33 0.53 0.30 23 0.29 0.41 11/20-11'27 l 0.20 0.36 1.5 0.36 0.65 034 2.8 032 0.49 11/27-12/04 0.21 0.35 1.5 0.34 0.49 0.31 23 031 0.40 12/04-12/18* 0.22 0.41 13 0.42 0.80 0.44 2.9 032 0.65 12/18-01/02 0.16 1.6 026 029 0.49 0.26 22 024 037 1.2 1991 O1/02-01109 0.71 13 1.2 23 1.2 - 103 032 1.1 1.6 5.5 ~

01/09-01/15 0.61 0.61 1.1 0.57 4.6 0.50 0.81 2.5

'TWO WEEKS

" ELEVATED LLD DUE TO LOW AIR VOLUfE

TABLE 2.2 AERIALLY TRANSPORTED GAMMA ACTIVITY (LLD Values in fCi m-3)

NUCLIDES SAMPLING PERI _QQ Co 57 Co 60 Nb-95 Zr-95 Ru-103 Ru-106 Cs-137 C e.141 Cc-144 1991 01/15-01/22 0.16 0.32 0.32 0.50 0.31 2.4 0.27 0.43 1.3 01/22 01/29 0.18 0.33 036 0.57 0.33 2.7 030 0.45 1.5 01/29-02/05 0.21 038 037 0.65 0.47 2.8 032 0.67 1.6 02/05-01/14 0.20 0.35 038 0.53 0.39 2.6 031 0.58 1.5 02/14-02/21 0.14 0.25 028 0.46 0.29 1.7 0.20 0.43 1.1 02/21-02/28 0.16 0.27 032 0.50 0.28 2.3 023 0.43 1.2 02i28-03/07 0.19 0.35 032 0.59 032 2.4 0.26 0.45 1.4 j 03/07-03/14 0.18 0.36 032 0.56 0.29 2.4 0.29 0.41 1.5 03/14-03/21 0.14 0.28 0 24 0.42 022 1.9 021 0.29 1.1 03/21-03/28 0.13 0.26 0.22 0.34 0.17 1.7 0.20 0.26 1.0 03/28-04/04 0.16 0.27 0.21 0.33 021 1.8 0.21 0.25 1.1 04/04-04/11 0.17 0.28 020 0.32 0.21 1.6 021 0.26 1.2 E O4/11-04/18 0.18 0.29 021 0.31 0.20 1.6 0.21 0.24 1.2 04 > 18 - 0 4 /2 5 0.20 0.25 022 0.29 0.21 1.5 0.20 023 1.1 04/25-05/02 0.19 0.24 0.21 0.29 0.19 1.4 0.21 0.22 1.1 05/02-05/09 0.19 0.25 0.22 0.18 0.18 1.5 023 0.24 1.2 05/09-05/16 0.21 0.22 0.19 0.19 0.22 1.6 0.24 0.21 13 05/16-05/23 0.19 0.19 0.17 0.18 0.20 1.5 0.20 0.26 1.4  ;

O5/23-05/30 0.17 0.18 0.21 0.19 0.22 1.6 0.21 0.31 1.5 O5/30-06/06 0.21 0.20 0.19 0.20 0.24 1.4 0.22 030 1.4 06/06-06/12 0.19 0.19 0.20 0.21 0.25 13 0.27 034 1.5 06/12 06/18 0.21 0.17 0.23 0.25 0.30 1.4 025 035 1.6 06/18-06/25 0.12 0.19 0.19 0.28 0.15 1.4 0.17 0.21 0.91*

06/25-07/02 0.07 0.13 0.13 0.22 0.13 0.85 0.96 0.19 0.53 07/02-07/09 0.08 0.13 0.14 0 23 0.14 0.88 0.98 0.20 0.52 07/09-07/16 0.09 0.14 0.14 022 0.12 0.86 0.94 0.21 0.55 NEW AIR SAMPLERS INSTALLED

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TABLE 2.3 REGULATORY LIMITS, ALERT LEVELS, AND BACKGROUND LEVELS FOR '

AIRBORNE RADIOACTIVITY (fCl m*3) i REGUI.ATORY ALERT AVERAGE NC. i NUCLIDE LLMLI LEVEL BACKGROUND LEVEL l

GROSSALPHA 20 10 4 I GROSSBETA 1000 500 100 i Cs 137 5 x 105 10 2 l Ce 144 2 x 105 100 o_ l l

Ru 106 2 x 105 30 0 f

I131 1 x 105 jo o (

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Reference:

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

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3. MILK (TABLE 3.1)

Milk samples are collected each month from the Campus Creamery, the Lake Wheeler Road Dairy and the Randleigh Dairy Farm. i The FDA's Proventive Action Guide (PAG) for 1131 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.

TAB LE 3.1 1131 IN COWS' MILK (pCl liter-1 2,1 o) LLD - 2 pCi liter 1 pCiliter 1 _

D61E CAMPUS CREAMERY LAKE WHEELER RANDLEIGH JULY 1990 - r 2.4 s 2,4 s 2.5 AUGUST 1990 s1.6 s 1.6 s 1.6 SEPTEMBER 1990 s 3.9 s 3.8 s 3.7 OCTOBER 1990 .s 2.6 s 2.9 c. 2.9 NOVEMBER 1990 s 1.8 s 1.9 s 1.8 DECEMBER 1990 s 3.3 s 3.3 s 3.2 JANUARV 1991 s 1.8 s 1.8 s1.8 FEBRUARY 1991 s 1.6 s 1.6 s 1.6 MARCH 1991 s 1.7 s 1.8 s 1.8 APRIL 1991 s 1.7 s 1.7 s 1.8 MAY 1991 s 2.5 s 2.4 s 2.6 JUNE 1991 s 1.0 m 1.0 s 1.0 JULY 1991 s 2.4 s 2.0 s 2.2 12

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4. SURFACE W ATER (TABLES 4.1 AND 4.2)

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

- 0.4 pCiliterl and - 0.6 pCiliter1, respectively. For gross alpha activity the Alert Levelis 5 pCiliter1 and the Regulatory Limit is 1E pCilitari. For gross beta activity the Alert Levelis 12.5 pCi liter 1 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 radionuclides present. Surface water samples analy:ed during this period have not shown the presence of any gamma emitters above the detection limits specified in Table 4.2.

TABLE 4.1 GROSS ALPHA AND BETA ACTIVITY IN SURFACE WATER (pCiliter-1 2 2 o)

  • LLD a - 0.4 pCiliter 1 LLDp - 0.4 pCl liter 1 oCiliterl CFGS CFES DME LCCATA ALPHA S THIRD OUARTER 1990 ON < 0.5 2.2 1 0.4 OFF < 0.6 2.8 : 0.5 FOURTH QUARTER 1990 ON < 0.7 1.7 : 0.4 OFF < 0.6 1.6 : 0.4 FIRST QUARTER 1991 ON < 0.5 2.0 : 0.4 OFF 0.7 2 0.5 1.6 : O A SECOND QUARTER 1991 ON < 0.4 < 0.4 OFF < 0.4 < 0.4
  • LLD VALUES ARE DETERMINED QUARTERLY l3

TABLE 4.2 LOWER LIMITS OF DETECTION FOR SEVERAL GAMMA EMITTERS IN SURFACE WATER FROM NCSU ERSL ANALYSIS NUCLIDE LLD (oCiliter 1)

Co-60 5.4 Zn 65 13.8 Cs 137 5.3 Cs 134 5.9 Sr-85 16,7

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

  • LLO VALUES ARE DETERMINED QUARTERLY I

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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 activh'es 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 LCCATION f pC1 a-1_hj DECEMBER 1990 NORTH CAMPUS 1.0 1 0.1 DECEMBER 1990 SOUTH CAMPUS 1.1 : 0.1 DECEMBER 1990 EASTCAMPUS 1.6 1 0.1 DECEMP" $ 1990 WEST CAMPUS 1.2 0.1 JUNE 1991 NORTH CAMPUS 4.2 2 0.2 JUNE 1991 SOUTH CAMPUS 2.6 : 0.1 JUNE 1991 EAST CAMPUS 4.5 0.2 JUNE 1991 WEST CAMPUS 2.8 1 0.1

  • LLD values are determined semiannually 15

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> .. e-Table 5.2 - LLD VALUES FOR GAMMA EMITTERS IN VEGETATION MIKUDE LLD (oCi oram 1)

Co 60 0.01 Zn 65 0.02 Cc137 0.01 Cs-134 0.01 Sr-85 0.01 Ru 103 0.01 Nb 95 0.01 Zr 95 0.02 L

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6. THERMOLUM!NESCENT 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 0.5.1

'l 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 for the period 07/10/90 to 04/29/91. i 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

- 18 20 mR per quarter year.

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TABLE 6.1 ENVIRONMENTAL TLD EXPOSURES (mR!OUARTER YEAR il 0 )

DATE WITHERS RIDD!CK BROl33HTOrJ LIBRARY PUtSTAR STACK DAVID CLARK CO MTl 07/10/90-10/02/90 12.Si0.5 21.011.1 18.Gi0.9 ' 20.610.9 12.710.4 12.310.5 13.6 1.3 10/02/90-01/04/91 16.710.6 24.613.1 20.412.4 23.112.1 12.4 1.3 15.8 1.2 17.9 0.9 01/04i91-04/29/91 19.2 0.8 28.510.9 23.811.0 30.114.4 16.611.4 16.6 0.4 19.210.7 E

04/29/91-07/10/91 -----

DATA tJOT YET AVAllABLE ----- -----

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7. QUALITY COf4 TROL INTERCOMPARISON PROGRAfd  ;

The Environmental Radiation Surveillance Laboratory of the Radiation Protection Office has panicipated in the U. S. EPA Environmental Laboratory Intercomparison Studies Program during this report'og period. The objective of this program is to provide laboratories performing .onvironmental radiation measurements with unknowns to test fncir analytical techniques. The retutts of the intercomparison studies are given in Table 7.1 a k. 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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TABLE 7.1a GROSS ALPHA ACTIVITY AIR FILTER INTERCOMPARISON STUDY- l 31 AUGUST 1990 The known value for gross alpha activity is 10.0 pCi/tiltor with an expected laboratory precision 5.0 (1s.1 determination).

I NCSU EtMRONMENTAL LABORATORY RESULTS l ALPHA Exper. Ang anal Normalized deviation Lab Re1J. W Res. 3 Siama (R + SR) heraae (grand avo) Anown) I CA 12.0 11.0 11.0 0.58 0.118 11.33 0.30 0.46  !

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i STATISTIC AL SUMM ARY OF 179 PARTICIPANTS Statistic Retoondents Non-outhors Mean 12.44 Grand Avg 12.21 i Std. Dev. 3.09 2.57 Variance 9.54 6.58

% Coef. of Var. 24.83 21.01

% deviation of mean from known value 24.39 22.12 Norm dev, of mean from known value 0.79 0.86 Median 12.00 12.00

% deviation of median from known value 20.00 20.00 Norm. dev, of median from known value 0.65 0.78 .

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1 TABLE 7.1b GROSS BETA ACTIVITY AIR FILTER INTERCOMPARISON STUDV-31 AUGUST 1990 j The known value for gross beta activity is 62.0 pCVfilter with an expected laboratory precision of l 5.0 (1s,' 1 determination). I l

NCSU- ENVIAONVENTAL LABORATORY AESULTS GROSS '

Exper. Rng anal Normalized deviation Lab- H211 BA:L.2 Res. 3 Siama (R . SR) Average farand.avo)(known)

CA 63.0 61.0 62.0 1.00 0.236 62.00 0.92 0.00 STATISTIC AL

SUMMARY

OF 179 PARTICIPANTS Statistic Remndents Non. outliers Mcan 79.81 Grand Avg 64.66 Std. Dev. 154.68 6.77 Variance 23925.42 45.84

% Coef. of Var. 193.80 10.47

% deviation of mean from known value 28.73 4.29

. Norm, dev. of mean from known value 0.12 0.39 Median 63.83 63.67

% deviation cf median from known value 2.96 2.69 Norm, dev. of median from known value 0.01 0.25 21

TAB LE 7.1c 137Cs ACTIVITY AIR FILTER INTERCOMPARISON STUDY -

31 AUGUST 1990 The known value for Cesium 137 activity is 20.0 pCi/ filter witti an expected laboratory precision of 5.0 (1s,1 determination).

NCSU ENVIRONMENTAL LABORATORY RESULTS l

137 Cs Exper. Rng anal Normalized deviation Lab h M Rg5 9gma, (R + SR) Averace forand avoHknown)

CA 25,00 24.00 25.0 0.58 -0.118 24.67 0.68 1.62 STATISTIC AL

SUMMARY

OF 179 PARTICIP ANTS Statistic Rermndents Nen.outhers Mean 23.17 Grand Avg 22.70 Std. Dev. 5.25 3.91 Variance 27.58 15.28

% Coef, of Var. 22.67 17.22

% deviation of mean from known value 15.84 13.48 Norm, dev, of mean from known value 0.60 0.69 Median 22.67 22.67

,  % deviation of median from known value 13.33 13.33 Norm. dev. of median from known value - 0.51 0.68 22 ,

TABLE 7.1d GROSS ALPHA ACTIVITY IN WATER INTERCOMPARISON STUDY -

21 SEPTEMBER 1990 The known value for gross alpha activity is 10.0 pCi/ liter with an expected laboratory precision of 5.0 (1s,1 determination).

NCSU ENVIRONMENTAL LABORATORY RESULTS GROSS ALPHA Exper. Rng anal Normalizca deviation W W P_c:J M Sigma (R + SR) Average (crand.avolfknown)

CA 6.0 7.0 7.0 0.58 0.118 6.67 1.16 1.15 STATISTIC AL

SUMMARY

OF 197 PARTICIPANTS Statistic Resonndents Non-outt'ers Mean 10.60 Grand Avg 10.01 Std. Dev. 7.11 3.12 Variance 50.60 9.75

% Coel, of Var. 67.11 31.20

% deviation of mean from known value 6.00 0.07 Norm. dev. of mean from known value 0.08 0.00 Median 10.00 10.00

% deviation of median from known value 0.00 0.00 Norm. dev. of median from known value 0.00 0.00 23

4 TABLE 7.1e GROSS BETA ACTIVITY IN WATER INTERCOMPARISON STUDY-21 SEPTEMBER 1990 The known value for gross beta activity is 10.0 pCVliter with an expected laboratory precision of 5.0 (1s,1 determination).

1 NCSU - ENVIRONMEfCAL LABORATORY RESULTS GROSS BETA 1 Exper. Rng anal Normalized deviation )

M Ect.2 Ec1J (R + SR) Averace Lab Sicma {arand-avoyk nown)

CA 11.0 12.0 12.0 0.58 0.118 11.67 0.26 0.58 l

l STATISTICAL

SUMMARY

OF 197 PARTICIPANTS Statistic Rescondants Non-outtiers Mean 12.38 Grand Avg - 10.91 Std. Dev. 9.91 2.25 Variance 98.18 5.08

% Coef.of Var. 80.07 20.66

% deviation of mean from known value 2175 9.10 Norm. dev. of mean from known value 0.24 0.40 Median 17.00 11.00

% deviation of median frorn known value 10.00 10,00.

Norm. dev. of median from known value 0.10 0.44 a

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i TA pl? ? " ' - GROSS ALPHA ACTIVITY AIR FILTER INTERCOMPARISON STUDY -

29 MARCH 1991 The known value for gross alpha activity is 25.0 pCi/ filter with an c:pected laboratory precision of 6.0 (1s,1 determination).

i NCSU ENVIRONMENTAL LABORATORY RESULTS l l

ALPHA l Exper. Rng anal Normalized deviation Lab Res.1 - ML.2 Res. 3 Siama (R + SRI Averace (giand.avoifknown) ,

CA 27.0 27.0 28.0 0.58 0.098 27.33 0.69 0.67  ;

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' STATISTIC AL

SUMMARY

OF 165 PARTICIPANTS

- Statistical &soondents Non.outl>ers Mean 30.84 Grand Avg 29.73 Std. Dev. 10.44 5.93-Variance 109.06 35.18 >

% Coel, of Var. 33.87- 19.95

% deviation of mean from known value 23.35 18.92

- Norm. dev, of mean from known value 0.56 0.80 Median 29.00 28.67

% deviation of median from known value 16.00 14.67.

Norm. dev, of median from known value 0.38 0.62 25

TABLE 7.1g GROSS BETA ACTIVITY AIR FILTER INTERCOMPARISON STUDY 29 MARCH 1991 The known value for gross beta activity is 124.0 pCi/ filter with an expected laboratory precision of 6.0 (1s 1 determination).

NCSU ENV!RONMENTAL LABORATORY RESULTS DIla Exper. Rng anal Normalized deviation Lab Eca.1 Res.2 Res. 3 Siam 3 (R + SR) Averace fatand.avo)(known)

O\ 127.0 130.0 132.0 2.52 0.492 129.67 0.13 1.64 STATISTICAL

SUMMARY

OF 165 PARTICIPANTS Statistic Resonndents Non. outliers Mean 130.13 Grand Avg 130.11 Std. Dev. 17.24 13.60 Variance 297.16 185.01

% Cool, of Var. 13.25 10.45

% deviation of mean from known value 4.94 4.93 Norm dev.of mean from known value 0.36 0.45 Median 129.00 129.00

% deviation of median from known value 4.03 4.03 Norm, dev. of median from known value 0.29 0.37 26

i ..

  • s . s l I

l

- TAB LE 7.1h 137Cs ACTIVITY AIR FILTER INTERCOMPARISON STUDY 29 M ARCH 1991 The known value for Cesium 137 activity is 40.0 pCi/ filter with an expected laboratory precision of 5.0 (1s,1 determination).

NCSU - ENVIRONMENTAL LABORATORY RESULTS l

137 Cs Exper. Rng anal Normalized deviation l Lab HEL.1 Res.2 Res 3 Siama (R + SR) Averace forand avo)(known)

ON 40.0 40.0 40.0 0.00 0.000 40.00 -1.60 0.00 l

STATISTICAL

SUMMARY

OF 165 PART!CIPANTS -

Statistic Resoondents Non outliers Mean 47.13 Grand Avg 44.61 Std. Dev. 21.38 7.62 Variance 457.24 58.10

% Coef.of Var. 45.37 17.09  ?

% deviation of mean from known value 17.82 11.53 Norm. dev. of mean from known value 0.33 0.60 Median 44.50 44.33

% deviation of median from known value 11.25 10.83 Norm. dev, of median from known value 0.21 0.57 l

h

?

27

J' J I

i l

l l

TABLE 7.11 GROSS ALPHA ACTIVITY IN WATER lNTERCOMPARISON STUDY 17 MAY 1991 The known value for gross alpha activity is 24.0 pCi/ liter with an expected laboratory precision of 6.0 (1s,1 determination). l NCSU - ENVIRONMENTAL LABORATORY RESLILTS GROSS ALPHA Exper. Ang anal Normalized deviation Lab Res 1 Eg.:L,2 Hei,,2 Sigma (R + SR) Averaae forand.ava)(known)

CA 24.0 25.0 26.0 1,00 0.197 25.00 1.17 0.29 STATIST! CAL

SUMMARY

OF 209 PARTICIPANTS Statistic. Resoondents Non outliers Mean 21.10 Grand Av0 20.94 Std. Dev. 7.18 6.63 Variance 51.59 43.91

% Coef, of Var. 33.95 31.64

% deviation of mean from known value -11.85 12.74 Norm. dev. of mean from known value -0.40 0.46 Median 21.33 21.33

% deviation of median from known value 11.11 11.11

.. Norm. dev. of median from known value -0.37 0.40 28

e .

r i.

TABLE 7.1J GROSS DETA ACTIVITY IN WATER INTERCOMPARISON STUDY 17 MAY 1991 ,

The known value for gross beta activity is 46.0 pCi1 iter with an expected laboratory precision of 5.0 (1s,1 determination).

NCSU - ENVIRONMENTAL LABORATORY RESULTS

, GROSS BETA

[

Exper. Rng anal Normalized deviation  ;

Lab Res 1 Res.2 Res.3 Siama (R + SRJ Average (arand-avo)(known)

O\ 48.0 -49.0 48.0 0.58 0.118 48.33 1.25 0.81 t

I STAT!STICAL

SUMMARY

OF 209 PARTICIPANTS

{

SJatistic Resonndents Non outfiera Mean 44.80 Grand Av0 44.73 f Std. Dev. 14.76 7.73 i Variance ~ 217.91 59.74

% Coef. of Var. 32.55 17.28

% deviation of mean from known value 2.61 2.77 Norm, dev. of mean from known value -0.08 0.16 [

Median 45.00 45.33

  • /c deviation of median from known value -2.17 1 A5-Norm, dev. of median from known value -0.07 -0.09 i

P r

i i

P 5

29

. -' ' ]

I

., .. I i

l l

l i

TABLE 7.1k TRITIUM IN WATER INTERCOMPARISON STUDY 22 JUNE 1990' I The known value for tritium activity is 2933.0 pCi/ liter with an expected laboratory precision of l 358.0 (1s,1 determination). l l

l l

NCSU . ENVIRONMENTAL LABOR ATORY RESULTS j 3g i Exper. Rng anal Normalized deviation Lab Egn.1 Pes 2 BgL S $!qma (R + SR) Averaae Mnd.avalfknown)

CA 3579.0 3597.0 3751.0 94.54 0.284 3642.33 3.27 3 43 STATISTIC AL

SUMMARY

OF 176 PARTIC' PANTS Statistic - Rotmndents Non outliers Mean 2S62.05 Grand Avg 2966.81 Std. Dev. 452.56 28S.64 Variance 204810.19 81593.06

% Coef. of Var. 15.28 9.63

% deviation of mean from known value 0.99 1.15 Norm, dev, of mean from known value 0.06 0,12 Median 2982.67 2986.67

% deviation of median from known value 1.69 1.83 Norm, dev, of median from known value 0.11 0.19 l

  • These results have been inc!uded in this report as they were received after submission of the -

1989-90 report.

t I

5 L

30 l

l

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

K 40) and those radionuclides (e.g., Be 7) v.hich 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. ACKNOWLEDGMENI.S This office is greatly indebted to Mr. Bill Crocker for nis untiring efforts to obtain and install the new air campling systems r' eat appreciation is alsc expressed u Mr. Thomas Brackin and Mr. Stan Graar for their assistance w, , - 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 Davis.

31

e a o

. -. .o APPENDlX 1 l The vertical columns in Tables 7 are identil. d as columns 18 from left to right.

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

Columns 2,3,4: Laboratory rosults given in triplicato.

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

Column 6: Normalized rango valvo in ' moan rango + clandard error of the rango".

Column 7: Average value of the triplicato analysis.

Column 8: Normalized dev* ,n from the grand average value of alllaboratorios expressed I in omunits.

Column 9: Normalized deviation from the hiown value expressed in om Units.

{

l The following example calculation gives a set of data, the mean value, the experimental sigma, and the range. These statistics provido measures of the contralleadency and dispersion of the data. 4 The normalized rango is computed by first finding mean range, R, the controllimit, CL, and the standard error of the rango, OR. The normalized rango measures the disporsion of the data (precision) in such a form that control charts may be used. Control charts allow one to readily comparo past analytical performance with present performanco, in tho exarnple, the normalized rango equals 0.3 which is loss than 3 which is the upper control level. The precision of the raruits is acceptablo.  :

The normalized deviation is calculated by computing the devlation and the standard error of the mean, om. The normalized deviation allows one to measura centrallendency (accuracy) readily through tho l' use of control charts. Trends in analytical accuracy can bo determined in this manner. For this 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 is acceptable. L Finally, the experimental error of aillaboratories, the grand averago, and the normalized deviation from the grand averago are calculated in ordor to ascertain the pairformanco of all the laboratories as a ,,

group. Any bias in methodology or instrumentation may be indicated by thoso results.

p 32

I

. *o ExAPPLE CALCUL ATIONS Caperin. ental data:

Known value a ya 3??3 pct 3H /11ter urine on Septenter 24, 1974 Capectc0 laboratory precision a a

  • 357 pct / liter Laboratory Sample Actult 0 x1 3060 pCi/ liter 0 Ap 3060 pC1/11ter 0 a3 3240 pct / liter Mean
  • I h

I xt tal 9360 I e a e 3120 pct / liter N 3 nhere N

  • nunber of results a 3 Esperimental sigma = s Ih \g l

i I N it-1 A j/

I (At)? .

tal N s =

N-1 2 2 2 (3060 + 3060 + 32401 2 (3060) + (3060) + (3240) -

3 s =

2 s = 103.9 pCi/ liter Range a r r = lmaximumresult-minimumresult l r = l3240-3060j = 180 pCi/ liter 33 .

.s *

.. *s Range Analysis (RNG ANLY)* 1 Yean range a X Ke dg e ,,here 02 '

  • 1.693 for H
  • 3

= (1.693) ($57)

W = C04.4 pCi/ liter

. Control limit a CL CL = E

  • 3ag

= 0I 4

nere 04 " = 2.575 for N = 3

=

(2.575) (604.4)

CL = 1556 pC1/11ter Standard-error of the range a ag og = (R t 3ag - E)  : 3

  • (04 I - I)  ; 3

= (1556 - 604.4)  ; 3 og a 317.2 pCi/ liter Let range a r a wl + xaR = 180 pCi/ liter  :

Define normalized range = w+x for r > E, w = 1 then r a 5% t xag a Rt xag r-I or x =

OR r-R therefore w+x = 1*x = 1+

GR

'Rosenstein, ti., and A. S. Goldin,

  • Statistical Techniques for Quality Control of Environmental Radioassay," AOCS Report Stat-1, U.S. Department of healtn ~

Education and Welf are, PHS, Noventer 1964.

"From taDie " factors for Computing Control Limits," Handbook of Tables for Probability and Statistics, 2nd Edition The CnemicWAubber Co., Cleve17r.J. -

Ohio, 1960, p. 4T4.

34

Experimental sigma (all lacoratories) st 1

, [N \2 l r -

N (f a l 4,/

I (at)2 -

fal N st . .

I N-1 {

l (49345)2 162639133 15 k 14 Crand average

  • CA N

I Aj i=1 GA =

N 49345

)

15 CA = 3290 pCi/ liter Normali2ed deviation from the grand average

  • N0' Deviation of tne mean from the grand average = 0' D' = I- CA

= 3120 - 3290 0' = - 170 pCi/11ter O'

ND' = -

~ 170

= --

206.1 ND' a -

0.8 36

for r( R, A a 0 then r a wK + x ag = wK r

or u =~

R r

therefore wsx = w*O --

K since r < I, (180 < 604.4) 160 W f A 8 604.4 wt x = 0.30 l Normalized deviation of the rean from tne kno=n value a hD )

Deviation of mean from the known va1ue O D = x-p

= 3120 - 3273 0 = - 153 pCi/ liter Standard error of the mean a om g, . JL R

357 d

am

  • 206.1 pCi/ liter 0

no . --

om

. - 153 7E~f ND = - 0.7 Control limit a CL CL = (p 30m)

Warning Limit = WL WL * (p 2am) 35

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