ML051250207

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Ncsu Pulstar Annual Report
ML051250207
Person / Time
Site: North Carolina State University
Issue date: 05/02/2005
From: Cook A
North Carolina State University
To:
Document Control Desk, Office of Nuclear Reactor Regulation
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North Carolina State University is a land- Nuclear Reactor Program grant university and a constituent institution of The University of North Carolina Department of Nuclear Engineering Campus Box 7909 Raleigh, NC 27695-7909 919.515.2321 919.515.5115 (fax)

URL:www.ne.ncsu.edu/NRP/reactor_

program.html May 2, 2005 TO. Nuclear Regulatory Commission Document Control Desk US. Nuclear Regulatory Commission Washington, DC 20555 RE: NCSU PULSTAR Annual Report License No. R-120 Docket No. 50-297 In compliance vith section 6.7.4 of the North Carolina State University PULSTAR Technical Specifications, our Nuclear Reactor Program staff has prepared the attached Annual Report for the period 01 July 04 - 31 December 2004. The shortened period reflects the shifting of the reporting period to coincide with the calendar yvar.

If you have any question please feel free to call me at (919) 515-4602.

Sincerely, Andrew T Cook Associate Director Nuclear Reactor Program IVR1

NORTH CAROLINA STATE UNIVERSITY DEPARTMENT OF NUCLEAR ENGINEERING PULSTAR REACTOR ANNUAL REPORT DOCKET NUMBER 50-297 For the Period: 01 July 2004 - 31 December 2004 The following-report is submitted in accordance with Section 6.7.4 of the North Carolina State University PULSTAR Reactor Technical Specifications:

6.7.4.a Brief Summary:

Reactor operations have been routine during this reporting period.

i Operating experience Including a summary of experiments performed.

Reactor operations have been routine during this reporting period. The following is a brief summary of the types of experiments performed:

Teaching Laboratories, Short Courses, and Research

  • Core thermal power measurements
  • Dynamic reactivity measurements
  • Axial power and peaking factor measurements (flux mapping)
  • Reactor power determination using photodiode arrays
  • Neutron diffusion length in graphite by foil activation Neutron fluence and spectral measurements
  • Neutron transmutation doping of silicon
  • In-core detector certification
  • Radiation damage determination to fiber optic material
  • Accelerated lifetime testing for nuclear detectors
  • Neutron radiography
  • Positron production facility Neutron Activation Analysis
  • Crude oil
  • Food samples
  • Fish tissues 1 of 5
  • Laboratory animal tissue
  • Human hair, nails, and urine
  • Polymers and plastics
  • Sediment/soil/rocks Silicon crystals Textiles
  • Water ii Changes in Performance Characteristics Related to Reactor Safety:

None iii Results of Surveillance, Tests, and Inspections:

The reactor surveillance program has revealed no significant or unexpected trends in reactor systems performance during this reporting period. The Reactor Safety and Audit Committee (RSAC) performed its annual audit for the facility and determined that all phases of operation and supporting documents were in compliance.

Health physics surveillance of reactor primary coolant water showed no fission products and that activity is below 10 CFR 20, App. B, Table 3 limits.

6.7.4.b Total Energy Output:

1 1.0 Megawatt-days Reactor was Critical:

370.9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> Cumulative Total Energy Output Since Initial Criticality:

965.5 Megawatt-days 6.7.4.c Number of Emergency and Unscheduled Shutdowns:

Emergency Shutdowns - none Unscheduled Shutdowns - Three

1. 30-AUG-04: Linear Over-Power SCRAM due to shimming out too close to the auto-range setpoint. No actual over-power condition existed.
2. 04-NOV-04: Manual SCRAM due to fire alarm. Fire alarm triggered by burning popcorn in a microwave.
3. 08-NOV-04: Linear Over-Power SCRAM due to shimming out too close to the auto-range setpoint. No actual over-power condition existed.

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6.7.4.d Corrective and Preventative Maintenance:

Preventative maintenance, tests and calibrations are scheduled, performed and tracked utilizing the PULSTAR Surveillance File System. Each major component of the Reactor Safety System defined in Section 3.3, and all surveillance required by Section 4 of the Technical Specifications are monitored by this file system to ensure that maintenance and calibrations are performed in a timely manner. All historical data relating to those components, in addition to many other sub-systems, are maintained in these files.

6.7.4.e Changes In Facility, Procedures, Tests, and Experiments:

Summary:

Design Changes None.

Document Changes Numerous procedures where revised including Operational and Health Physics procedures. All changes were reviewed to determine whether or not a 10CFR50.59 evaluation was required.

Based on the reviews, none required a 10CFR50.59 evaluation..

Other Changes License Amendment 15 was submitted to the Nuclear Regulatory Commission for approval.

Included in the submittal was a shifting in the annual reporting period to coincide with the calendar year. Also included was a removal of a service hatch leading into the operations boundary.

6.7.4.f Radioactive Effluent:

Liquid Waste (summarized by quarters)

Radioactivity Released During the Reporting Period:

(1) (2) (3) (4)' (5)

Period Number of Total Total Diluent Tritium Batches PCi Volume Liters PCi

__________ ~~~Liters __ _ _ __ _ _ _ _ _

01 JAN - 31 MAR 04 1 23 3420 0 23 01 APR - 30 JUN 04 2 54 5710 212 53.5 01 JUL-30 SEP 04 0 0 0 0 0 01 OCT-31 DEC04 ' 2 50 5400 9362 49 (6) 49 pCi of tritium was released during this reporting period.

125.5 pCi of tritium was released during this year.

50 pCi of total activity was released during this reporting (7) period.

127 pCi of total activity was released during this year.

'Based on gross beta activity only. Tritium did not require further dilution.

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ii. Identification of Fission and Activation Products:

The gross beta-gamma activity of the batches in (1) above were less than 2x10-5 pCi/ml. Isotopic analyses of these batches indicated low levels of typical corrosion and activation products. No fission products were detected.

iii. Disposition of Liquid Effluent not Releasable to Sanitary Sewer System:

All liquid effluent met the requirements of 10 CFR 20 for release to the sanitary sewer.

Gaseous Waste (summarized monthly)

1. Radioactivity Discharged During the Reporting Period (in Curies) for:

(1) Gases:

Year Month Total Time Curies Hours 2004 JANUARY 744 0.140 FEBRUARY 696 0.222 MARCH 744 0.312 APRIL 720 0.156 MAY 744 0.138 JUNE 720 0.016 JULY 744 0.117 AUGUST 744 0.285 SEPTEMBER 720 0.454 OCTOBER 744 0.118 NOVEMBER 720 0.114 DECEMBER 744 0.114 REPORTING PERIOD 4416 1.202 (JULY - DECEMBER)_

TOTAL 8784 2.183 (2) Particulates with a half-life of greater than eight days:

Particulate filters from the Stack Particulate Monitoring Channel were analyzed upon removal.

There was no particulate activity with t, 2>8days 1 indicated on any filter during this reporting period.

ii. Gases and Particulates Discharged During the Reporting Period:

(1) Gases:

Total activity of argon-41 released was 1.202 curies in this reporting period and 2.183 curies in 2004.

The yearly average concentration of argon-41 released from the PULSTAR reactor facility exhaust stack during this period was 8.7x10 p9Ci/cc. This is below the regulatory limit of I x104 pCi/cc given in 10 CFR 20 Appendix B. Dose calculations for the fiscal year were performed using the "COMPLY" code with results less than the 10 mrem constraint level given in IOCFR20.

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(2) Particulates:

See gaseous waste i.(2) above.

Solid Waste from Reactor'

i. Total Volume of Solid Waste Packaged 21 ft3 of dry uncompacted waste 14 ft3 of dried resins, II. Total Activity Involved 0.82 mCi in dry compacted waste 0.23 mCi in dried resins iii. Dates of shipments and disposal Transfer to the university broad scope radioactive materials license was made on 27 August 2004.

The University Environmental Health and Safety Center arranges disposal of hazardous wastes.

6.7.4.g Personnel Radiation Exposure Report:

Up to twenty-eight individuals were monitored for external radiation dose during the reporting period. Collective dose for this reporting period was 0.721 person-rem and 1.767 person-rem fro 2004. Individual doses ranged from 0.001 to 0.157 rem with an average of 0.063 rem. No visitors required official monitoring during 2004.

6.7.4.h Summary of Radiation and Contamination Surveys Within the Facility:

Radiation and contamination surveys performed within the facility by the PULSTAR staff indicated that:

  • External radiation levels in the majority of areas were 2 mrem/h or less.
  • External radiation levels in the remaining areas were higher due to reactor operations.
  • Contamination in most areas was not detectable.
  • When contamination was detected, the area or item was confined or decontaminated.

6.7.4.1 Description of Environmental Surveys Outside of the Facility:

See Attachment A prepared by the Radiation. Safety Division of the Environmental Health and Safety Center at the end of this document.

Perimeter surveys were performed adjacent to the Reactor Building by the PULSTAR staff and indicated that:

  • External radiation levels were at background levels for most areas (10 prem/h).

Contamination was not detectable.

  • Net external radiation levels ranged up to 40 prem/h in some areas while the reactor was operating at power. However, external radiation levels were at background levels in routinely occupied spaces.

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ATTACHMENT A PULSTAR REACTOR ENVIRONMENTAL RADIATION SURVEILLANCE REPORT FOR THE PERIOD JULY 1, 2004 - December 31, 2004 NORTH CAROLINA STATE UNIVERSITY ENVIRONMENTAL HEALTH AND SAFETY CENTER RADIATION SAFETY DIVISION by Ralton J. Harris Environmental Health Physicist

TABLE OF CONTENTS PAGE NO.

1. INTRODUCTION 1 Table 1 Environmental Monitoring Programs for the PULSTAR Reactor 2
2. AIR MONITORING 3 Table 2.1 Location of Air Monitoring Stations 3 Table 2.2 Aerially Transported Gamma Activity (LLD Values) 4 Figures 2a-2e Airborne Gross Beta Activities 5 -9 Table 2.3 Regulatory Limits, Alert Levels and Background Levels for Airborne Radioactivity 10
3. MILK Table 3.1 1-131 in Cow's Milk 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 Tables 7.1a & 7.1b 19 -20
8. CONCLUSIONS 21 APPENDIX I 22- 26 APPENDIX 2 27
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.

1

Table 1:

Environmental Monitoring Programs for the PULSTAR Reactor at North Carolina State University Sample Activity Conducted Previous Current Basis For Measured By Frequency Frequency Measurement Stack Gross N.E. Continuous Continuous 10 CFR 20 Gases Gamma T.S. 6.7.4 Stack Gross Beta N.E. Monthly Monthly 10 CFR 20 Particles Indiv. N.E. T.S. 6.7.4 Gamma Emitters Water from Gross Beta N.E. Prior to Prior to 10 CFR 20 Reactor Gross N.E. Discharge Discharge T.S. 6.7.4 Facility Gamma N.E. (- Monthly) - Monthly City of Tritium Raleigh Ordinance Air/Particles Gross Beta RSD/EHSC Weekly Quarterly 10 CFR 20 at 5 Indiv. RSD/EHSC Weekly 10 CFR 20 Campus Gamma Stations* Emitters Air/Dosage TLD RSD/EHSC Quarterly Quarterly 10 CFR 20 at 8 Dosimeter Campus Stations+

Surface Gross Beta RSD/EHSC Quarterly Quarterly NCSU Water Indiv. RSD/EHSC Quarterly Quarterly NCSU Rocky Gamma Branch Emitters Creek Vegetation Gross Beta RSD/EHSC Semi- Alternate years NCSU NCSU Gamma RSD/EHSC annually Alternate years NCSU Campus II I I Milk 1-131 RSD/EHSC Monthly Alternate years NCSU Local Dairy Abbreviations Used in Table:

N.E. = Nuclear Engineering/Reactor Facility; RSD/EHSC = Radiation Safety Division.

  • These 5 stations include:

Withers, Riddick, Broughton, Hill Library and Environmental Health & Safety Center.

+These 8 stations include: the PULSTAR stack, a control station (EHSC) and the 5 air sampling stations, and North Hall.

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

Air monitoring is performed continually for one week during each of four (4) quarters during the year. The data shows the normal fluctuations in gross beta activity levels expected during the year. Figures 2a through 2e show bar graphs of gross beta activity (fCi/cubic meter vs. sampling quarters per year). The highest gross beta activity observed was 15.5 fCiM-3 at the D.H. Hill Library station during the week of 09/03/04 to 09/10/04. The campus average for the 3rd and 4th quarters of 2004 was 11.9 fCiM-3 .

Table 2.2 lists LLD values for several gamma emitters that would be indicative of fission product activity. No gamma 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' DISTANCE2 ELEVATION 3 (meters) (meters)

BROUGHTON SOUTHWEST 125 -17 LIBRARY NORTHWEST 192 +11 RIDDICK SOUTHEAST 99 -14 WITHERS NORTHEAST 82 -6 EH & S CENTER WEST 1230 -3 NORTH HALL NORTHEAST 402 -4 1DIRECTION - DIRECTION FROM REACTOR STACK 2DISTANCE - DISTANCE FROM REACTOR STACK 3 ELEVATION - ELEVATION RELATIVE TO THE TOP OF THE REACTOR STACK A wind rose is included in Appendix 2 to indicate the prevailing wind direction trends for the years 1996-2003.

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Table 2.2 Aerially Tra nsported Gamma Acti ity LLD values fClcubic meter

_______NUCLIDES SAMPLING PERIOD Co-57 Co-60 Nb-95 Zr-95 Ru-103 Ru-106 Cs-137 Ce-141 Ce-144 2004 __ _ _ _ _ _ _ _ _ _ _ _ _ _

09/03 - 09/10 0.21 0.44 0.29 0.46 0.27 2.25 0.33 0.36 1.21 11/12 - 11/19 0.21 0.44 0.28 0.48 0.28 2.48 0.35 0.34 1.28

Broughton Hall 25 Airborne Gross Beta Activity Figure 2a 20 09/03-09/10 2004 11/12-11/19 1 15 2004 2

Co E

610

%a-.

5 0

1 2 3 4 Quarters per Year

Withers Hall 25 T Airborne Gross Beta Activity Figure 2b 20 +/-

09/03-09/10 2004 C) 15 -

E

.0 U

C., 10 - 11/12-11/19 2004 5+

0 4 - l 1 2 3 4 Quarters per Year

Riddick Hall 25 T Airborne Gross Beta Activity Figure 2c 20 - 11/12-11/19 09/03-09/10 2004 2004 L-a) 4-15 +/-

E 10 +/-

'4-51-0 4-1 2 3 4 Quarters per Year

D.H. Hill Library 25 - Airborne Gross Beta Activity Figure 2d 20 -

11/12-11/19

a. 15- 2004 0)

E 09103-09/10 2004 10 S.-

5-0 I V I I I 1 2 3 4 Quarters per Year

Environmental Health & Safety Center Airborne Gross Beta Activity 25 Figure 2e 20 11/12-11/19 2004 2 15 ON E

.2 510 09/03-09/10 5 2004 0

1 2 3 4 Quarters per Year

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

REGULATORY ALERT AVERAGE N.C.

NUCLIDE LIMIT LEVEL BACKGROUND LEVEL GROSS ALPHA 20 10 4 GROSS BETA* 1000 500 14.7 ; 3.1

  • Cs-1 37 5 X 105 10 2 Ce-144 2 x 105 100 0 Ru-1 06 2 X 10 30 0 2 x 1o5 1-131 - 10 0
  • These data represent a range of annual average values measured in North Carolina.

Data courtesy of Dale Dusenbury of the N.C. Division of Radiation Protection.

Reference:

Environmental Radiation Surveillance Report 1986-88, State of N.C. Radiation Protection Section 10

3. MILK (TABLE 3.1)

Milk samples are collected in alternate years from the Campus Creamery and the Lake Wheeler Road Dairy and analyzed for 1-131. No data is available for the period covered by this report. The next sample collection will be in 2005.

TABLE 3.1A 1-131 IN COW'S MILK (pCi Liter" +/- 2 a) LLD - 3 pCi Liter 1 pCi Liter-'

DATE Campus Ceamery Lake VVheeler No data No data 11

4. SURFACE WATER (TABLES 4.1 AND 4.2)

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 value for gross alpha and beta activities is - 0.4 pCi Liter'. For gross alpha activity the Alert Level is 5 pCi Liter' and the Regulatory Limit is 15 pCi Liter'. For gross beta activity the Alert Level is 5 pCi Liter' and the Regulatory Limit is 50 pCi Liter'.

Samples with gross alpha or beta activities exceeding these Alert Levels would require gamma analysis to identify the radionuclides present. All the results are consistent with the presence of naturally-occurring radionuclides and none of the gamma emitters listed in Table 4.2 were detected.

TABLE 4.1 GROSS ALPHA AND BETA ACTIVITY IN SURFACE WATER (pCi Liter 1 +/- 2a)

  • LLD, - 0.4 pCi Liter' LLDO - 0.4 pCi Liter' pCi Liter' GROSS GROSS DATE LOCATION ALPHA BETA THIRD QUARTER 2004 ON < 0.4 1.6 +/-0.4 OFF <0.4 1.6 +/-0.4 FOURTH QUARTER 2004 ON <0.4 3.1 +/-0.7

- OFF <0.4 2.9 +/-0.7 12

TABLE 4.2 LLD VALUES FOR GAMMA EMITTERS IN SURFACE WATER NUCLIDE LLD (fCi Liter-)

Co-60 0.4 Zn-65 0.7 Cs-1 37 0.3 Cs-1 34 0.4 Sr-85 0.4 Ru-1 03 0.3 Ru-1 06 3.0 Nb-95 0.4 Zr-95 0.5 13

5. VEGETATION (TABLE 5.1 & 5.2)

Tables 5.1 gives gross beta activities for grass samples collected on the NCSU Campus. Table 5.2 lists LLD values for several gamma emitters. The vegetation sampling is performed in alternate years.

No data is available for this report period. The next sample collection will be in 2005.

TABLE 5.1 GROSS BETA ACTIVITY IN CAMPUS VEGETATION

  • LLD - 0.5 pCi g-1 SAMPLE DATE SAMPLE LOCATION (PCi qf +/- 2a)

NORTH CAMPUS No data SOUTH CAMPUS No data EAST CAMPUS No data VEEST CAMPUS No data 14

TABLE 5.2 LLD VALUES FOR GAMMA EMITTERS IN VEGETATION NUCLIDE LLD (pCi gram1 )

Co-60 0.01 Zn-65 0.02 Cs-1 37 0.01 Cs-1 34 0.01 Sr-85 0.01 Ru-1 03 0.01 Nb-95 0.01 Zr-95 0.02 15

6. THERMOLUMINESCENT DOSIMETERS (TLDs) (TABLE 6.1)

TLD analysis is contracted to Landauer, Inc. for determination of ambient gamma exposures.

Exposures are integrated over a three-month period at each of the five air monitor stations listed in Table 2.1 and inside the PULSTAR Reactor stack and at North Hall. A control station is located in Room 107 of the Environmental Health & Safety Center. Table 6.1 gives the data for these eight (8) locations.

The exposures (dose equivalents) are reported as millirem per quarter year. Readings which fall below the dosimeters' minimum measurable quantities (i.e., 1 millirem for gamma radiations and 10 millirems for beta radiations) are reported by the contract vendor with the designation "M ". The observed readings are all within the expected range for natural background radiation levels.

Historically, dosimeter readings for D.H. Hill Library monitoring station have often been higher than those for the other campus stations. Pursuant to a recommendation made in the 'NCSU PULSTAR 2001 Annual Self Assessment", two additional TLDs are included at the D.H. Hill Library station to supplement the existing dosimeter. These two additional dosimeters are a routine part of the quarterly monitoring schedule.

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TABLE 6.1 ENVIRONMENTAL TLD EXPOSURES (mrem/QUARTER YEAR)

DATE WITHERS RIDDICK BROUGHTON DH HILL* EH&S PULSTAR STACK NORTH CONTROL 2004 07/01-09/30 M 5 M 13,15,16 4 2 M M,M 10/01-12/31 M 8 M 15,18,14 M 5 2 M,4

  • The entries for D.H. Hill are for three (3) independent dosimete readings for that station.

The "CONTROL" column indicates the use of dual control dosimeters for all the monitoring periods.

The designation "M" is used by the contract vendor for reporting dose equivalents below the minimum measurable quantity which is 1 millirem for gamma radiation and 10 millirem for beta radiation I I

7. QUALITY CONTROL INTERCOMPARISON PROGRAM In the past, he Environmental Radiation Surveillance Laboratory (ERSL) of the Radiation Safety Division has analyzed samples provided by the U.S. DOE Environmental Measurements Laboratory Quality Assurance Division Program. DOE terminated this program in June 2004 at the conclusion of the QAP 60 environmental matrices distribution session.

The Mixed-Analyte Performance Evaluation Program administered by the DOE Radiological and Environmental Sciences Laboratory (RESL) has replaced this program. The objective of this program is to provide laboratories performing environmental radiation measurements with unknowns to test their analytical techniques.

The ERSL of the North Carolina State University Radiation Safety Division has been allowed to begin participation in MAPEP and receive blind samples of radiological analytes during the semiannual distributions. The first samples received were during the MAPEP Test Session 12 and the results have been included in this report. Results for more environmental matrices will be included in the next report.

For each reported radiological analyte, the laboratory result and the MAPEP RESL reference value is used to report a relative bias:

%Bias = (100)(Laboratory Re sult - RESL Re ferenceValue)

RESL ReferenceValue The relative bias will place the laboratory result into one of three categories:

Acceptable ................. Bias

  • 20%

Acceptable with Waming ... 20% < Bias

  • 30%

Not Acceptable ................ Bias > 30%

The results of the intercomparison studies are given in Tables 7.1 (a&b), and are stated in the Si unit becquerel (Bq) as required by the MAPEP reporting protocol.

In addition to MAPEP, the ERSL conducts an intralaboratory QC program to track the performance of routine radioactivity measurements. The types of calculations employed for this program are shown in an example calculation in Appendix 1.

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TABLE 7.1a GROSS ALPHA & BETA ACTIVITY AIR FILTER -- INTERCOMPARISON STUDY 01 May 2004 The sample consists of one 47 mm diameter simulated filter containing Th-230 and Sr-90. The reported values and the reference values are given in Bq/filter.

Sample ID: MAPEP-04-GrFI2 Analyte NCSU Result Reference Flag  % Bias Acceptance Uncertainty Value Range Value Gross Alpha 0.05 0.37 A - 86.5 >0.0 - 0.8 0.01 Gross Beta 1.06 1.21 A -12.4 0.6-1.8 0.11 Statistical Summary Analyte T(1) 7 A(2) Grand Mean Standard Reference Acceptance l Deviation Value Range Gross Alpha 57 53 0.15 0.09 0.37 60.0

- 0.8 Gross Beta 58 56 1.23 0.15 1.21 0.6-1.8 Gross Alpha Flags:

A = Result Acceptable, Bias s +/-f 100% with a statistically positive result at 2 standard deviations.

N = Result Not Acceptable, Bias >+/- 100% or the reported result is not statistically positive at 2 standard deviations.

Gross Beta Flags:

A = Result Acceptable, Bias

  • i 50% with a statistically positive result at 2 standard deviations.

N = Result Not Acceptable, Bias > +/- 50% or the reported result is not statistically positive at 2 standard deviations.

T = Total Number of Laboratories Reporting Analyte A = Number of Laboratories with 'Acceptable' Performance.

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TABLE 7.1b MULTINUCLIDE WATER - INTERCOMPARISON STUDY 01 May 2004 The sample consists of a spiked, 500 mL aliquot of acidified water (-5%v/v HNO3). The reported values and the known values are given in Bq/Liter.

Sample ID: MAPEP-04-MaWI2 Analyte NCSU Result Reference Flag  % Bias Acceptance Uncertainty Value Range Value Cs-134 178.820 208 A - 14.0 145.60-270.40 3.171 Cs-137 236.336 250 A - 5.5 175.00-325.00 7.336 co-57 172.525 185 A - 6.7 129.50-240.50 6.750 Statistical Summary Analyte T(1) A(2) Grand Mean Standard Reference Acceptance Deviation Value Range Cs-134 72 X 71 186.70 14.26 208 145.60-270.40 Cs-137 74 73 244.57 13.06 250 175.00-325.00 co-57 70 69 188.88 11.72 185 129.50-240.50 Flags:

A = Result Acceptable, Bias s 20%

W = Result Acceptable with Warning, 20% < Bias

  • 30%

N = Result Not Acceptable, Bias > 30%

T(1) = Total Number of Laboratories Reporting Analyte A(2) = Number of Laboratories with 'Acceptable' Performance 20

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 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.

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APPENDIX I 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, aR. 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, am. 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. Any bias in methodology or instrumentation may be indicated by these results.

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EXAMPLE CALCULATIONS Experimental Data:

Known value = p = 3273 pCi 3H/Liter on September 24, 1974 Expected laboratory precision = a = 357 pCi/liter Sample Result X, 3060 pCi/liter X2 3060 pCi/liter X3 3240 pCi/liter Mean = x N 9360 x = LX1 x=i

= 3120 pCi/liter 3

where N = number of results = 3 Experimental sigma = s N

lN (a xi )2 Z(Xj)2 i- N s-I

)2 2 206+3060+3240)2

= (3060 +(3060) +(3240)2(360 3 s \ 2 s = 103.9 pCi/liter Range = r r = I maximum result - minimum result I r = 13240 - 30601 r = 180 pCi/liter 23

Range Analysis (RNG ANLY)*

Mean range = R R - d2 O where d2** = 1.693 for N = 3

= (1.693) (357)

R - 604.4 pCi/liter Control limit = CL CL = R + 3R

- D4 R where D4** = 2.575 for N = 3

= (2.575) (604.4)

CL = 1556 pCi/liter Standard error of the range = OR OR = (R + 3aR - R) + 3

- (D 4R-R) + 3

= (1556 - 604.4) + 3 OR = 317.2 pCi/liter Let Range = r = wR + XaR = 180 pCi/liter Define normalized range = w + x for r >RB w = 1 then r = wR + XOR = B + XOR r-R or r- R therefore w+x = 1 +x = 1 +

  • Rosentein, M., and A. S. Goldin, "Statistical Techniques for Quality Control of Environmental Radioassay,"

AQCS Report Stat-1, U.S. Department of Health Education and Welfare, PHS, November 1964.

    • From table "Factors for Computing Control Limits," Handbook of Tables for Probability and Statistics, 2nd Edition, The Chemical Rubber Co., Cleveland, Ohio, 1968, p. 454.

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forr5R, x=0 then r = wR + XaR = wR r

or w=

R r

therefore w + x = w+0 =

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

604.4 w+x=0.30 Normalized deviation of the mean from the known value = ND Deviation of mean from the known value = D D = x-,

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

am =

/N 357

=-

%,3 cm = 206.1 pCi/liter D

ND =

-153 206.1 ND = -0.7 Control limit = CL CL = (p +/- 3am) 25

Warning limit = WL WL = (II+/- 20m)

Experimental sigma (all laboratories) = st N (Zxi)

_ I N NJ j162639133 p49345)2 14 St = 149 pCi/liter Grand Average = GA N

EXi GA- '-

N 49345 15 GA = 3290 pCi/liter Normalized deviation from the grand average = ND' Deviation of the mean from the grand average = D' D' = - GA

= 3120 - 3290 D'= -170 pCi/liter N'D D-CH)

-170 206.1 ND' = -0.8 26

Joint Frequency Distribution Based on Hourly Observations from Raleigh-Durham Airport July 1, 1996 - August 24, 2003 W E 10.56 Calms included at center.

0.1 3 6 12 18 24 Rings drawn at 5% intervals.

Wind flow is FROM the directions shown.

Wind Speed ( Miles Per Hour) No observations were missing.

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