ML20091P473
| ML20091P473 | |
| Person / Time | |
|---|---|
| Site: | North Carolina State University |
| Issue date: | 06/30/1995 |
| From: | Dudziak D, Mayo C, Perez P North Carolina State University, RALEIGH, NC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9509010222 | |
| Download: ML20091P473 (41) | |
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l North Carolina State University
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Nuclear Reactor Program 1)epartment of Nuclear Engineering Box 7909 Haleigh. NC 27695 7909 (919) 515-2321 FAX (919) 515 5115 25 August 1995 U.S. Nuclear Regulatory Commission ATTN: ' Document Control Desk Washington, DC 20555
Subject:
NCSU PULSTAR Annual Report Docket No. 50-297
Dear Sir:
-In compliance with Section 6.7.5 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 1994 through 30 June 1995. Please feel free to contact Mr. Perez at (919) 515-4602 if you have any questions or comments.
Sincerely, CAs.s '
Pedro B. Perez Associate Director Nuclear Reactor Program
~'
g Charles W. Mayo DonaldJ. Dudziak 4 -
Director, Nuclear Reactor Program Head, Department of Nuclear Engineering PilP/CWM*b copy w/ attachments:
Director of Regulatory operations. Region !!
Mr. Stephen J. Dilyj U. S. Nuclear Regulatory Commission Reactor Operations Manager Dr. James A. Knopp, Chairman Mr. David Rainer, Director Radiatior Proncetion Committec Environmental llcalth and Safety Center Chairman Dr. II. Merrick liarrison Reactor Safety and Audit Committee Radiation Protection Officer Dr. Ralph K. Cavin Ill, Dean Mr. Mark Poirier College of Engineering ANI/MAELU 0
9509010222 950630 Ii PDR -ADOC R_
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b North Carolina State Univertity is a land-grant unwersity and a constituent institution of The University of North Carolina.
DEPARTMENT OF NUCLEAR ENGINEERING PULSTAR REACTOR ANNUAL REPORT DOCKET NUMBER 50-297
~
For the Period: 01 July 1994 - 30 June 1995 The following report is submitted in accordance with Section 6.7.5 of the PULSTAR Technical Specifications:
6.7.5.a Brief Summarv Full power reactor operations resumed in May 1995 after repairs to the primary cooling system were completed. Repairs consisted of building a subterranean concrete vault enclosing the new nitrogen-16 delay tank and previously buried primary cooling system pipes.
(1) Reactor Operating Exnerience:
The NCSU PULSTAR Reactor has been utilized for the following:
a.
Teaching and Short Courses 127.8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> b.
Faculty and Graduate Student Research 252.6 c.
Isotope Production 84.9 d.
Neutron Activation Analysis 938.4 e.
Beam Tube Facilities 0.0 f.
Nuclear Training (Utilities) 30.7 g.
PULSTAR Reactor Training 8.5 h.
Reactor Cal / Measurements & Surveillance 71.8 i.
Reactor Health Physics Surveillance 6.5 j.
Reactor Sharing 5.3 TOTAL 1,526.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> Same reporting period 1993-1994 1,936.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> 1
J
s PUISTAR REACroR ANNUAL REPORT 2-DOCKET NUMDER $0 297 01 July 1994 - 30 June 1995 4
A cross section of exoeriments oerformed in the reactor:
a.
Neutron Activation Analysis of filters, tissue, bone, protein solutions, hair, sediments / soil, rain / river water, vegetation, wood pulp, dyes, paper, electronic components, fibers, plastics, resins, coal, fly ash, graphite.
b.
Reactor thermal power measurements for teaching laboratories.
- c.. Neutron diffusion length measurements in graphite and scattering from SiO in the thermal column facility.
2
. d.
Determination of coolant flow rates using nitrogen-16 gamma.
e.
Prompt gamma analysis of boron.
f.
Neutron fluence and spectral measurements.
g.
Transmutation of silicon for semiconductor research.
h.
Radiation damage effects on scintillation fibers and photodiodes.
(2) Changes in Performance Characteristics Related to Reactor Safety:
None
'(3) Results of Surveillance. Tests. and Inspections:
The reactor surveillance program has revealed no significant or unexpected trends in reactor systems performance during this report period.
6.7.5.b Total Enerev Output:
1213 Megawatt hours 5.1 Megawatt days Pulse Operations:
None Reactor was Critical:
618.2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> Cumulative Total Energy Outout Since Initial Criticality:
18,943.9 Megawatt hours 789.3 Megawatt days
e PULTTAR REACroR ANNUAL REPORT 3
DOCKET NUMBER 50-297 01 July 1994 30 June 1995
.6.7.5.c Number of Emergency and Unscheduled Shutdowns:
Unscheduled Shutdowns - 2 total (1) Linear Channel Overpower Reverse (0.11 MW)
(2) Pneumatic Transfer sample failed to return Inadvertent SCRAM: - 5 total (3) Off-site power interruption - 1 (4) Spurious signals - 4 Explanation of (1) above:
The Linear Power Channel was indicating 85 kW when an electrical noise spike drove the channel to 110 kW causing an Overpower Reverse. The Linear Channel Reverse trips at 73.3% of any range. See 6.7.5.d below.
Explanation of (2) above:
An end cap on a polyethylene shuttle used in the pneumatic system cracked, separated and subsequently jammed the sample in the tube at the core terminus.' A retrieval tool was fabricated and the shuttle and sample were recovered.
Explanation of (3) above:
self-explanatory Explanation of (4) above:
A trip circuit in the Intermediate Range Channel and the Safety Channel will generate a SCRAM upon loss of forced primary flow or if the safety flapper valve opens when power is above 15 percent. Recently the PULSTAR Reactor has been operating up to 10 percent power in natural convection cooling mode with the safety flapper valve open in accordance with Section 3.9 of the PULSTAR Operations Manual. In this mode of operation, electrical noise spikes generated within the console electrical system instantaneously exceeded the trip circuit setpoint and generated a SCRAM. This was verified by testing several combinations of console switch movements which caused a SCRAM signal to occur. The Intermediate Range Channel was tested or calibrated after 1
... -.~ -.-.. -.
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_ PULYTAR REACTOR ANNUAL REPORT 4
DoCKIfr NUMBER 50-297
{
01 July 1994 30 June 1995 each occurrence and found to be operational. Reactor operational limits were reduced to 8.5% power to give greater margin between the actual power level 4
and the trip circuit setpoint, which helped to limit the number of electrical spikes that could cause a SCRAM. Since initial criticality most reactor 7
operations were conducted at or near full power. During that time these trip circuits were always in their enabled state and as long as forced primary flow was present and the safety flapper valve was shut, no SCRAM would occur. A new Intermediate Range instrument has been purchased and is undergoing acceptance testing.
l 6.7.5.d Ma_ior Maintenance Operations:
\\.
(1) Investigation of random noise spikes displayed on the Linear Power i
Channel recorder indicated that they were not being generated in the amplifier, I
high voltage power supplies or in the recorder, so the Linear Power Channel j
compensated ionization chamber (CIC) was replaced with a spare. After j
calibrations were performed the reactor was returned to operation.
i (2) As part of the effort to repair the 0.7 gallon per hour primary system leak discovered in late 1993, the excavated N-16 Delay Tank was moved to the PULSTAR bay for testing. The tank was designed to hold 100 psig at 100 F.
j Normal operating pressure is about 18 psig (static head) with temperatures i
ranging from 70 to 120 'F. The first test performed was similar to the PUIJSTAR triennial surveillance hydrostatic pressure drop test, which j
pressurizes the system to 60 psig and the pressure decrease is monitored (due to j
valves in the system) and check for leaks. The N-16 Delay Tank held pressure and no leaks were observed. The second test pressurized and maintained a hydrostatic pressure of 85 psig (approximately 5 times normal operating pressure). While checking the tank for leaks after reaching 85 psig, a metallic snap sound was heard and then a very small water stream was observed near one of the dished ends of the tank. After several unsuccessful repair attempts 3
by an ASME certified welder, a new 600 gallon tank was fabricated to ASME Unfired Pressure Vessel Code and installed in the primary piping system. In l
addition to the repairs, a subterranean vault enclosing the formerly buried tank and primary piping was also constructed. After testing and performing all pending surveillance, the PULSTAR was returned to full power operation.
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i PU13 TAR REACroR ANNUAL REPORT 5
DoCKirr NUMDER $0 297 01 July 1994 30 June 1995 l
6.7.5.e Changes in Facility. Procedures. Tests. and Experiments:
1.
Design Changes (a) DC 94-2 authorized the construction of the subterranean piping vault.
(b) DC 94-3 installed a differential pressure alarm monitoring reactor building negative pressure.
(c) DC 95-1 authorized the installation of a new Source Range Monitor in the reactor console to replace the original instrument.
2.
Procedure Changes (a) PC 3-95 was Revision 13 to the PULSTAR Operations Manual. This documented the changes the Startup Checklists required by the new i
subterranean vault.
(b) A total of eight procedures have been revised (minor editorial changes) and fifteen new Health Physics calibrations procedures have been reviewed and approved by the Radiation Protection Committee.
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s PUISTAR RIMCroR ANNUAL REPORT 6
j DOCKLT NUMBER 50 297 01 July 1994 30 June 1995
)
6.7.5.f. Radioactive Effluent:
A. Liquid Waste (summarized by quarters) 1.
Radioactivity Released During the Reporting Period:
(a)
(b).
(c)8 (d)2 (e)
No. of Total Tot. Vol.
Diluent Tritium Period Batches _ pCi Liters Liters Ci 01 Jul - 30 Sep 94 4
78 1.1E4 8.5E5 2
01 Oct - 31 Dec 94 3
13 9.4E3 2.0E4 16 01 Jan - 31 Mar 95 6
40 1.7E4 1.0E5 38 4
01 Apr - 30 Jun 95 2
32 6.8E3 2.0E4 29 (f) 163 Ci total activity released during this reporting period.
(g) 85 pCi of tritium were released during this reporting period.
2.
Identification of Fission and Activation Products:
The gross beta-gamma activity of the batches in (a) abcve were less than 2 x 10 pCi/ml. Isotopic analyses of these batches indicated low levels of 4
typical corrosion and activation products.
3.
Disposition of Liquid Effluent not Releasable to Sanitary Sewer System:
6 All batches of 1(a) above. when diluted by campus water (2.80 x 10 liters; the minimum daily campus intake) resulted in activity considerably less than 1 x 10 Ci/ml (10 CFR 20 limit). Therefore, all batches were 4
released to the sanitary sewer system.
I 4
i Increases in the total volume discharged from 01 Jan 95 to 31 Mar 95 were due to 8
hydrostatic testing and haining of the N-16 Tank and primary coolant piping.
2 Based on gross beta activity only. Tritium did not require further dilution.
0
e PUISTAR REAcroR ANNUAL REPORT 7
DOCKl?T NUMBER 50 297 01 July 1994 30 June 1W5 B. Gaseous Waste /,ummarized monthly) 1.
Radioactivity Discharged During the Reporting Period (in Curies) for:
(a)
Gases:
Total Time Year Period In Hours Curies 1994 01 Jul - 31 Jul 720 8.2E-2 01 Aug - 31 Aug 744 1.0E-1 01 Sep - 30 Sep 720 7.2E-2 01 Oct - 31 Oct 744 8.7E-2 01 Nov - 30 Nov 720 6.3E-2 01 Dec - 31 Dec 744 7.2E-2 1995 01 Jan - 31 Jan 744 9.0E-2 01 Feb - 28 Feb 672 7.3E-2 01 Mar - 31 Mar 744 7.5 E-2 01 Apr - 30 Apr 720 1.8E-1 01 May - 31 May 744 1.5E-1 01 Jun - 30 Jun 720 2.0E-1 Totals 8,760 1.25 (b)
Particulates with a half-life of greater than eight days:
Filters from the particulate monitoring channel were analyzed upon removal. There was no particulate activity indicated on any filter during this reporting period.
2.
Gases and Particulates Discharged During this Reporting Period:
(a)
Gases:
Total activity of argon-41 release was 1.25 curies.
The yearly average concentration of argon-41 released from the PULSTAR reactor facility exhaust stack during this period was 8.3 x 10* Ci/cc. This is below the regulatory limit of 4
1 x 10 Ci/cc. (10 CFR 20 Appendix B)
(b)
Particulates:
See gaseous waste 1.(b) above.
e PUI5rAR REACroR ANNUAL REPORT g
DoCKirr NUMBER S297 01 July 194 - 30 June 1995
- Solid Waste from Reactor
- 1. Total volume of solid waste - 29 ft' (0.8 m')
- 2. Total activity of solid waste - 1 mci
- 3. Dates of shipments and disposal:
02 May 95 Chem-Nuclear Systems Inc. (CNSI) - 14 ft' (0.4 m')
In storage awaiting disposal - 15 ft' (0.4 m')
6.7.5.g ' Personnel Radiation Exposure Report' Twenty-five members of the faculty and staff were monitored for external radiation exposure during the reporting period. Fourteen of the twenty-five received measurable exposure which ranged from 0.010 to 0.030 rem. Total person-rem for the faculty and staff was 0.180.
Approximately 53 film badges were issued to graduate students, temporary staff, short course participants, and visitors. Radiation exposures ranged to 0.030 rem. The majority of these exposures were in the "no measurable exposure" range.
6.7.5.h Summarv of Radiation and Contamination Surveys Within the Facility
)
Radiation and contamination surveys performed within the facility by the PULSTAR staff indicate:
external radiation levels in most areas were <0.5 mrem /h contamination levels in most areas were not detectable when contamination was detected, the area or item was confined or decontaminated external radiation levels were as expected i
i
' Compiled and prepared by the Radiation Protection Division.
PUL5rAR REACroR ANNUAL REPORT 9
DoCKLT NUMBER 50 297 01 July 1994 30 June 1995 6.7.5.i Description of Environmental Surveys Outside of the Facility See Attachment A prepared by the Radiation Protection Division of the Department of Environmental Health and Safety.
Perimeter surveys performed by the PULSTAR staff indic ': :
external radiation levels were at background levels for most areas (10 rem /h) contamination levels were not detectable Net external radiation levels ranged up to 20 rem /h in some areas when the reactor was operating at power. However, external radiation levels were at background levels in routinely occupied spaces.
l 1
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NORTH CAROLINA STATE UNIVERSITY i
DEPARTMENT OF
)
ENVIRONMENTAL HEALTH AND SAFETY RADIATION PROTECTION DIVISION i
i ENVIRONMENTAL RADIATION SURVEILLANCE REPORT FOR THE PERIOD j
JULY 1,1994 - JUNE 30,1995 i
ATTACHMENT A i
1 i
PREPARED BY RALTON J. HARRIS I
AND JERILIN E. PAITH
~ -
TABLE OF CONTENTS 4
PAGE NO.
i i
1.
INTRODUCTION 1
2.~
-- AIR MONITORING 1
-l Table 2.1 Location'of Air Monitoring Stations 1
Figures' 2a-2e Airborne Gross Beta Activities 2-6 l
Table 2.2 Aerially Transported Gamma Activity (LLD Values) 7-8 Table 2.3 Regulatory Limits,' Alert Levels and Background Levels for Airbome Radioactivity 9
3.'
MILK C
Table 3.1 10 4.
SURFACE WATER Table 4.1 Gross Alpha and Beta Activity in Surface Water 11 Table 4.2 LLD Values for Gamma Emitters in Surface Water 12 5.
VEGETATION Table 5.1 Gross Beta Activity in Campus Vegetation 13 Table 5.2 LLD Values for Gamma Emitters in Vegetation 14 6.
THERMOLUMINES' CENT DOSIMETERS 15 Table 6.1 Environmental TLD Exposures 16 7.
QUALITY CONTROL INTERCOMPARISON PROGRAM 17 Tables 7.1a - 7.1g 17 - 23 8.-
CONCLUSIONS 24 9.
. ACKNOWLEDGMENTS 24 i
APPENDlX 1 25 - 29 l
=_j
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)
Provide 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.
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.
i week number). The highest gross beta activity observed was 31.5 fCim at the Riddick station during the week of 09-20-94. The annual campus average was 16.2 fCim. Instances of missing data for a monitor station are due to pump and electric
~
motor malfunctions, and power outages during building repairs in Riddick Hall.
4 Table 2.2 lists LLD values for several gamma emitters which would be indicative of fission product activity. No aamma 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 2
SITE DIRECTION DISTANCE ELEVATION (meters)
(meters)
BROUGHTON SOUTHWEST 125
-17 DAVID CLARK LABS WEST 500
-18 LIBRARY NORTHWEST 192
+11 RIDDICK SOUTHEAST 99
-14 WITHERS NORTHEAST 82
-6
' DIRECTION-DIRECTION FROM REACTOR STACK 2DISTANCE-DISTANCE FROM REACTOR STACK
" ELEVATION-ELEVATION RELATIVE TO THE TOP OF THE REACTOR STACK 1
CLARK 30 --
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Table 2.2 Aerially Transported Gamma Activity (fCi m E-3)
NUCLIDES SAMPLING PERIOD Co-57 Co-60 Nb-95 Zr-95 Ru-103 Ru-106 Cs-137 Ce-141 Ce-144 1994 06/28 - 07/05 0.18 0.25 0.30 0.54 0.28 2.30 0.25 0.45 1.41 07/05- 07/12 0.26 0.42 0.39 0.60 0.33 3.10 0.39 0.46 1.96 07/12 - 07/20 0.27 0.45 0.38 0.63 0.34 3.10 0.42 0.49 2.14 07/20- 07/26 0.17 0.40 0.33 0.59 0.30 2.80 0.29 0.37 1.43 07/26 - 08/02 0.19 0.39 0.33 0.59 0.30 3.10 0.32 0.36 1.47 08/02- 08/09 0.30 0.58 0.51 0.85 0.46 4.50 0.50 0.53 2.24 08/09- 08/17 0.19 0.39 0.35 0.65 0.35 3.30 0.33 0.44 1.52 08/17 - 08/23 0.19 0.37 0.35 0.58 0.33 3.10 0.38 0.39 1.58 08/23 - 08/30 0.20 0.38 0.34 0.57 0.31 3.10 0.34 0.37 1.58 08/30 - 09/06 0.18 0.32 0.30 0.50 0.29 2.70 0.31 0.33 1.39 09/06- 09/13 0.19
'O.39 0.34 0.54 0.29 2.80 0.35 0.35 1.45 09/13 - 09/20 0.17 0.33 0.28 0.53 0.28 2.70 0.29 0.33 1.33 09/20- 09/27 0.16 0.32 0.29 0.47 0.28 2.40 0.27 0.35 1.26 09/27-10/06 0.15 0.28 0.28 0.40 0.23 2.30 0.26 0.28 1.17 10/06-10/12 0.15 0.31 0.26 0.48 0.26 2.40 0.26 0.33 1.16 10/12-10/19 0.15 0.30 0.23 0.43 0.22 2.30 0.28 0.28 1.16 10/19-10/25 0.18 0.36 0.28 0.49 0.23 2.60 0.29 0.29 1.51 10/25 - 11/01 0.16 0.29 0.23 0.40 0.23 2.30 0.25 0.28 1.27 11/01 - 11/08 0.16 0.30 0.24 0.46 0.27 2.20 0.24 0.31 1.29 11/08 -11/15 0.16 0.29 0.25 0.43 0.29 2.30 0.26 0.31 1.31 11/15-11/22 0.18 0.31 0.26 0.44 0.29 2.40 0.27 0.33 1.38 11/22 - 11/29 0.19 0.32 0.28 0.43 0.28 2.60 0.29 0.30 1.46 11/29 - 12/06 0.17 0.31 0.36 0.66 0.49 2.30 0.24 0.34 1.32 12/06 -12/13 0.17 0.27 0.34 0.63 0.43 2.40 0.25 0.33 1.29 12/13 -12/20 0.17 0.29 0.25 0.53 0.36 2.10 0.24 0.31 1.29 12/20-12/29 0.13 0.22 0.23 0.43 0.26 1.90 0.20 0.37 0.96 12/29- 01/04 0.18 0.36 0.31 0.54 0.33 2.5 0.3 0.43 1.41 9
Table 2.2 Aerially Transported Gamma Activity (fCi m E-3)
~
NUCLIDES SAMPLING PERIOD CO-57 Co-60 Nb-95 Zr-95 Ru-103 Ru-106 Cs-137 Ce-141 Ce-144 1995 01/04 - 01/11 0.16 0.31 0.29 0.47 0.27 2.2 0.24 0.38 1.22 01/11 - 01/19 0.17 0.32 0.28 0.48 0.28 2.5 0.29 0.34 1.28 01/19-01/26 0.19 0.34 0.30 0.50 0.29 2.50 0.29 0.33 1.26 01/26 - 02/02 0.17 0.33 0.29 0.48 0.28 2.50 0.29 0.32 1.30 02/02- 02/09 0.18 0.32 0.31 0.46 0.29 2.6 0.27 0.31 1.29 02/09 - 02/16 0.16 0.31 0.3 0.45 0.28 2.5 0.26 0.3 1.33 02/16 - 02/23 0.19 0.35 0.33 0.47 0.31 2.6 0.25 0.36 1.38 02/23 - 03/02 0.18 0.32 0.34 0.49 0.32 2.5 0.27 0.35 1.31 1
03/02 - 03/09 0.16 0.31 0.33 0.48 0.35 2.6 0.28 0.38 1.29 03/09 - 03/16 0.17 0.3 0.32 0.49 0.33 2.5 0.26 0.33 1.28 '
03/16 - 03/23 0.18 0.29 0.3 0.47 0.31 2.5 0.27 0.32 1.29 03/23 - 03/30 0.16 0.3 0.3 0.48 0.3 2.6 0.29 0.34 1.3'.
03/30 - 04/06 0.18 0.31 0.33 0.50 0.31 2.60 0.31 0.33 1.27 j
04/06-04/13 0.16 0.33 0.35 0.43 0.30 2.50 0.30 0.30 1.26 04/13 - 04/20 0.17 0.34 0.38 0.41 0.33 2.60 0.31 0.31 1.35 04/20 - 04/27 0.19 0.31 0.35 0.39 0.36 2.50 0.33 0.30 1.29 04/27 - 05/04 0.18 0.30 0.34 0.38 0.35 2.50 0.34 0.29 1.31 05/04 - 05/11 0.16 0.30 0.28 0.44 0.28 2.30 0.25 0.35 1.24 05/11 -05/18 0.18 0.33 0.32 0.45 0.26 2.40 0.27 0.29 1.23 05/18-05/25 0.17 0.32 0.35 0.41 0.27 2.50 0.29 0.31 1.30 05/25 - 06/01 0.18 0.26 0.30 0.47 0.28 2.40 0.26 0.41 1.39 06/01 - 06/08 0.19 0.36 0.34 0.46 0.29 2.40 0.27 0.38 1.35 06/08-06/15 0.17 0.34 0.33 0.45 0.30 2.50 0.28 0.36 1.33 06/15 -06/22 0.17 0.33 0.39 0.40 0.31 2.50 0.29 0.37 1.35 06/22 - 06/29 0.18 0.34 O.38 0.37 0.30 2.50 0.28 0.36 1.33 O
TABLE 2.3 REGULATORY LIMITS, ALERT LEVELS, AND BACKGROUND LEVELS FOR AIRBORNE-RADIOACTIVITY (fCi m')
REGULATORY ALERT AVERAGE N.C.
NUCUDE LIMIT LEVEL BACKGROUND LEVEL GROSS ALPHA 20 10 4
GROSS BETA 1000 500 100 Cs-137 5 X 10 JO 2
8 Ce-144 2 X 10 100 0
5 Ru-106 2 X 10 30 0
5 1-131 1 X 10 10 0
5
Reference:
Environmental Radiation Surveillance Report 1986-88, State of N.C. Radiation Protection Section s
9
3.
MILK (TABLE 3.1)
Milk samples are collected each month from the Campus Creamery and the Lake Wheeler Road Dairy. Previously, samples were obtained from the Randleigh Dairy Farm but it is no longer operational.
TABLE 3.1 1-131 IN COWS' MILK (pCi liter 12 a) LLD ~ 3 pCl liter-'
4 pCi liter' DATE CAMPUS CREAMERY LAKE WHEELER JULY 1994 s 3.0 s 3.0 AUGUST 1994 s 3.0 s 3.0 SEPTEMBER 1994 s 3.0 s 3.0 OCTOBER 1994 s 3.0 s 3.0 NOVEMBER 1994 s 3.0 s 3.0 DECEMBER 1994 s 3.0 s 3.0 JANUARY 1995 s 3.0 s 3.0 FEBRUARY 1995 s 3.0 s 3.0 MARCH 1995 s 3.0 s 3.0 APRIL 1995 s 3.0 s 3.0 MAY 1995 s 3.0 s 3.0 JUNE 1995 s 3.0 s 3.0 t
4 10
~ 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 values for gross alpha and beta i
activities are - 0.4 pCl liter' and - 0.4 pCi liter', respectively. For gross alpha activity the Alert Levelis 5 pCi liter' and the Regulatory Limit is 15 pCiliter'.
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. The LLD values in Table 4.2 are for the second quarter of 1995.
TABLE 4.1 GROSS ALPHA AND BETA ACTIVITY IN SURFACE WATER (pCi liter' i 2a)
- LLDa - 0.4 pCl liter' LLD# ~ 0.4 pCi liter' pCi liter' GROSS GROSS DATE LOCATION ALPHA BETA THIRD QUARTER 1994 ON
< 0.4
< 0.4 OFF
< 0.4
< 0.4 FOURTH QUARTER 1994 ON
< 0.4
< 0.4 OFF
< 0.4
< 0.4 FIRST QUARTER 1995 ON
< 0.4
< 0.4 OFF
< 0.4
< 0.4 SECOND QUARTER 1995 ON
< 0.4
< 0.4 OFF
< 0.4
< 0.4
- LLD VALUES ARE DETERMINED QUARTERLY l
i l
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TABLE 4.2 'LLD VALUES.FOR GAMMA EMITTERS IN SURFACE WATER
.)
l NUCLIDE -
LLD (pCi liter')*
Co-60 0.4 I
Zn 0.7 Cs-137 0.3 Cs-134 0.4 E-Sr-85 0.4 l
Ru-103 0.3 Ru-106 3.0 s
Nb-95 0.4 Zr-95 0.5
- LLD VALUES ARE FOR THE 2ND QUARTER OF 1995 l
4 1
4
~
12-i i
.I
l 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. 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
SAMPLE DATE SAMPLE LOCATION (oCi a +2a)
DECEMBER 1994 NORTH CAMPUS 3.6 i 0.1 DECEMBER 1994 SOUTH CAMPUS 2.6 i 0.1 DECEMBER 1994 EAST CAMPUS 2.5 i 0.1 DECEMBER 1994 WEST CAMPUS 2.5 i 0.2 APRIL 1995 NORTH CAMPUS 2.8 i 0.1 APRIL 1995 SOUTH CAMPUS 2.6 i 0.1 APRIL 1995 EAST CAMPUS 2.7 0.1 i
APRIL 1995 WEST CAMPUS 2.8 0.1 l
- LLD values are determined semiannually 13
\\
.. ~
TABLE 5.2 LLD VALUES FOR GAMMA EMITTERS IN VEGETATION
' NUCLIDE LLD (pCl gram)* -
i Co-60 0.01 j
Zn-65 0.02 Cs-137 0.01 Cs-134 0.01 Sr-85 0.01 t
Ru-103 0.01 Nb-95 0.01-Zr-95 0.02 i
- LLD VALUES ARE FOR THE 2ND QUARTER OF 1995 i
i i
i 14
O 6.
THERMOLUMINESCENT DOSIMETERS (TLDs)
(TABLE 6.1)
TLD analysis is contracted to Teledyne isotopes for determination of ambient gamma exposures. The dosimeters are CaSO doped with dysprosium and have a manufacturer-4 stated sensitivity of 0.5 i 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 was located in 214 David Clark Laboratories during July, August, September, October 1994 and in Room 107 of the Environmental Safety Center during the remainder of this report period. A high exposure of 77.9 i 9.4 mR was recorded for the control station during the period 01/05/95 to 04/25/95. An explanation for this elevated exposure is not available, but may have been due to a defective TLD. Table 6.1 gives the data for these seven (7) monitoring 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 l
exposure rate of 20 mR per quarter year.
1 l
l t
l l
15
~.... -... -..... -.. -.
- - ~. - - - -------_____ - - --
TABLE 6.1.
ENVIRONMENTAL TLD EXPOSURES (mR/ QUARTER YEAR i 2s)
DATE
' WITHERS RIDDICK BROUGHTON LIBRARY DAVID CLARK PULSTAR STACK CONTROL
- 04/04/94 - 06/30/94 10.6 i 1.8 16.312.6 11.9 1.9 11.6 i 3.0 10.0 i O.6 10.4 1.1 11.4 i 2.8 06/30/94 - 09/28/94.
17.512.1 25.0 1.9 18.6 i.1.8 20.5 i 4.0 19.6 i 3.1 14.7 i O.5 17.6 i 1.3 09/28/94 - 01/11/95-15.6 i O 7 22.3'i 2.3 17.111.3 17.2 i O.6 22.7-i 8.4 13.9 0.2 17.0 i 1.4 01/05/95 - 04/25/95 13.6 i 2.6 18.0:13.7 15.5 i-5.0 16.2 i 6.3 26.8 i 8.8 12.1 i 2.8 77.9 i 9.4 04/25/95-06/30/95 DATA NOT YET AVAILABLE FOR THESE DATES e
- THIS DATA WAS UNAVAILABLE FOR INCLUSION IN THE 1993-1994 REPORT.
~
l h
w
.,w.
m,
7.
QUALITY CONTROL INTERCOMPARISON PROGRAM 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 unknowns to :est 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.
TABLE 7.1a GROSS ALPHA ACTIVITY IN WATER -INTERCOMPARISON STUDY 22 JULY 1994 The known value for gross alpha activity is 32.0 pCi/ liter with an expected laboratory precision of 8.0 (1s,1 determination).
NCSU - ENVIRONMENTAL LABORATORY RESULTS GROSS ALPHA 1
Exper.
Rng anal Normalized deviation Res.1 Res.2 Res.3 Siama (R + SR)
Averaae (arand-ava) (known) t 29.0 33.0 30.0 2.09 0.295 30.66 0.20
-0.29 STATISTICAL
SUMMARY
OF 241 PARTICIPANTS i
Statistic Respondents Non-outliers Mean 30.33 29.74 Std. Dev.
11.61 10.11 Variance 134.79 102.31
% Coei, of Var.
38.28 34.01
% deviation of mean from known value
-5.21
-7.07 Nor. dev. of mean from known value
-0.14
-0.22 Median 29.33 29.33
% deviation
-8.33
-8.33 Nor, dev. of median from known value
-0.23
-0.26 17
TABLE 7.1b GROSS BETA ACTIVITY IN WATER -INTERCOMPARISON STUDY 22 JULY 1994 The known value gross beta activity is 10.0 pCi/ liter with an expected laboratory precision of 5.0 (1s,1 determination).
NCSU - ENVIRONMENTAL LABORATORY RESULTS GROSS BETA Exper. Rng anal Normalized deviation Res.1 Res.2 Res.3 Slama (R + SR) Averaae (arand-ava) (known) 10.0 13.0 12.0 0.58 0.118 11.67
-1.12 0.58 STATISTICAL
SUMMARY
OF 241 PARTICIPANTS Statistic Respondents Non-outliers Mean 18.02 Grand Avg 14.91 Std. Dev.
31.47 3.74 Variance 990.10 13.96'
% Coef. of Var.
174.64 25.06
% deviation of mean from known value 80.17 49.06 Norm. dev. of mean from known value 0.25 1.31 Median 15.00 15.00
% deviation of median from known value 50.00 50.00 Nor dev. of median from known value 0.16 1.34 j
18
o e
TABLE 7.1c TRITIUM IN WATER -INTERCOMPARISON STUDY 5 AUGUST 1994 The known value for tritium activity is 0951 pCi/ liter with an expected laboratory precision of 995 (1s,1 determination).
5 NCSU - ENVIRONMENTAL LABORATORY RESULTS
'H
~
Exper.
Rng anal Normalized deviation Res.1 Res.2 Res.3 Siama (R + SR)
Averaae (arand-avo) (known) 10894.0 10630.0 10422.0 303.53 0.339 10648.7 1.74 1.22 STATISTICAL
SUMMARY
OF 214 PARTICIPANTS l
Statistic Respondents Non-outliers Mean 9389.64 Grand Avg 9651.86 Std. Dev 1581 38 696.62 Variance 2500775.46 485284.69
% Coef. of Var.
16.84 7.22
% deviation of mean from known value
-5.64
-3.01 Norm. dev, of mean from known value
-0.35
-0.43 Median 9683.33 9710.00
% deviation of median from known value
-2.69
-2.42 Nor, dev. of median from known value
-0.17
-0.35 19
l TABLE 7.1d GROSS ALPHA ACTIVITY AIR FILTER -INTERCOMPARISON STUDY 26 AUGUST 1994 The known value for gross alpha activity is 35.0 pCi/ filter with an expected laboratory preci.sion of 9.0 (1s,1 determination).
l NCSU - ENVIRONMENTAL LABORATORY RESULTS GROSS ALPHA Exper.
Rng anal Normalized deviation Res.1 Res.2 Res.3 Siama (R + SR)
Averaoe (arand-ava) (known) 35.0 35.0 35.0 0.00 0.000 35.00
-0.36 0.00 STATISTICAL
SUMMARY
OF 214 PARTICIPANTS Statistic Respondents Non-outliers Mean 39.50 Grand Avg 36.89 Std. Dev.
17.30 6.62 Variance 299.45 43.78
% Coef. of Var.
43.81 17.94
% deviation of mean from known value 12.85 5.40 Norm. dev. of mean from known value 0.26 0.29 Median 36.00 36.00
% deviation of median from known value 2.86 2.86 Nor. dev. of median from known value 0.06 0.15 20
TABLE 7.1e GROSS BETA ACTIVITY AIR FILTER -INTERCOMPARISON STUDY 26 AUGUST -1994 The known value for gross beta activity is 56.0 pCi/ filter with an expected laboratory precision of
- 10.0 (1s,1 determination).
NCSU - ENVIRONMENTAL LABORATORY RESULTS GROSS BETA' Exper.
Rng anal Normalized deviation Res.1 Res.2 Res.3 Siama (R + SR)
Averaae (arand-avo) (known) 60.0 59.0 60.0 0.58 0.059 59.67 0.10 0.64 STATISTICAL
SUMMARY
OF 214 PARTICIPANTS Statistic Resoondents Non-outliers Mean 60.65 Grand Avg 59.08 Std. Dev.
14.97 7.23 Variance 224.13 52.21
% Coef. of Var.
24.68 12.23
% deviation of mean from known value 8.30 5.50 Norm, dev. of mean from known value 0.31 0.43 Median 58.33 58.33
% deviation of median from known value -
4.17 4.17 Nor, dev. of median from known value 0.16 0.32
)
j 21
TABLE 7.1f Cs ACTIVITY AIR FILTER -INTERCOMPARISON STUDY "7
26 AUGUST 1994 The known value for Cesium-137 activity is 15.0 pCi/ filter with an expected laboratory precision of 5.0 (1s,1 determination).
NCSU - ENVIRONMENTAL LABORATORY RESULTS "7 Cs Exper.
Rng anal Normalized deviation Res.1 Res.2 Res.3 Siama (R + SR)
Averaae (arand-ava) (known) 18.0 18.0 18.0 0.00 0.000 18.00 0.49 1.04 I
1 STATISTICAL
SUMMARY
OF 214 PARTICIPANTS l
Statistic -
Respondents Non-outfiers Mean 17.17 Grand Avg 16.59 Std. Dev.
4.10 2.42 Variance 16.83 5.87
% Coef. of Var.
23.90 14.61 i
% deviation of mean from known value 14.40 10.59 Norm. dev. of mean from known value 0.53 0.66 Median 16.33 16.33
% deviation of median from known value 8.89 8.89 Nor. dev. of median from known value 0.33 0.55 l
I l
1 Q
TABLE 7.1g TRITIUM IN WATER -INTERCOMPARISON STUDY 10 MARCH 1995 The known value for tritium activity is 7435.0 pCi/ liter with an expected laboratory prec!sion of 774.0 (1s,1 determination).
l NCSU - ENVIRONMENTAL LABORATORY RESULTS N
Exper.
Rng anal Normalized deviation Res.1 Res.2 Res.3 Sioma (R + SR)
Averaoe (orand-avo) (known) 7134.0 7357.0 7219.0 41.46 0.060 7236.67
-0.15
-0.46 STATISTICAL
SUMMARY
OF 186 PARTICIPANTS Statistic Respondents Non-outliers l
Mean 7223.50 Grand Avg 7299.15 Std. Dev.
1020.24 682.97 Variance 1040885.03 466446.40
% Coef. of Var.
14.12 9.36
% deviation of mean from known value
-2.84
-1.83 Norm. dev. of mean from known value
-0.21
-0.20 Median 7236.67 7244.67
% deviation of median from known value
-2.67
-2.56 i
Nor. dev. of median from known value
-0.19
-0.28 23 i
i a
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.
A comparison of this reporting period to previous years indicates low levels of naturally occurring radioactivity, and there seems to have been a general decline in ambient levels during the past five years. However, the magnitude of this apparent decrease is not large and should not be regarded as a substantiated trend. -
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.
j The graphs and arrangement of this report are available due to the assistance of Ms. Jerilin E.
Paith.
2 4
2 24
i APPENDIX 1 The vertical columns in Tables 7 are identified as columns 1-8 from left to right.
Column 1,2,3:
Laboratory results given in triplicate.
Column 4:
Standard deviation (1s) of the experimental results.
Column 5:
Normalized range value in "mean range + standard error of the range".
Column 6:
Average value of the triplicate analysis.
. Column 7:
Normalized deviation from the grand average value of alllaboratories expressed in a units.
m Column 8:
Normalized deviation from the known value expressed in a, 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, a. The normalized range measures the dispersion of the data n
(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, a.. 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 waming 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.
I s
25
[.
EXAMPLE CALCULATIONS Experimental Datai Known.value = p = 3273 pCi 'H/ liter on September 24,1974 Expected laboratory precision = a = 357 pCi/ liter Samole
- Result X,
3060 pCi/ liter X
3060 pCl/ liter 2
-- X
- 3240 pCi/ liter 3
i
~ Mean = x 1
N
[ Xj 9360 3120 pCi/ liter
=
x
=
x-1
=
3 N
l where N = number of results = 3 Experimental sigma = s i
f N
([ X )3 y
i (X )'-
J s
=
g h
N-1 (l-(3060) 2+ (306 0) 2+ (3240) 8- (306 0 +3060+3240) 2 3
s
=
103.9 pCl/ liter s'
=
' Range.=
r l maximum result - minimum result l r
=
l 3240 - 3060 l r
=
180 pCl/ liter r
=
26
^
l Range Analysis (RNG ANLY)*
I 1
1 M'
j
' Mean. range
=
'R
_=
da where d " = 1.693 for N = 3 a
2 -
-(1.693) (357).
=-
R' 604.4 pCl/ liter -
=
CL Control limit
=-
R + 3a CL
=
n DR where D," = 2.575 for N = 3
=
(2.575) (604.4)
=
1556 pCilliter CL
=
Standard error of the range
=
an (R + 3a - R) + 3
=
an n
(D R - R) + 3
=
4 (1556 - 604.4) + 3
=
317.2 pCi/ liter
=
an Let Range = r = wM + xan = 180 pCl/ liter Define normalized range = w + x.
for r > M, w = 1 then.
. r = wR + xan = R + xag r '- R or X=
ER r-R therefore w+x=1+x=1+
- Rosenteln, M., and A. S. Goldin, " Statistical Techniques for Quality Control of Environmental Radioassay,"
AOCS 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 n
Edition, The Chemical Rubber Co., Cleveland, Ohio,1968, p. 454.
27 i,
,e for r s R, x = 0 then -
- r = wR + xan = wR r.
' o' r 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 -p
= 3120 - 3273 D = -153 pCi/ liter
- Standard error of the mean = a, c
a "
m VN 357
=
3 V3 a, = 206.1 pCi/ liter D
ND =
- m
-153
=
-206.1 N D = ' -0.7 -
Control limit = CL CL = (p i 3a.)
28'
ij g
-p
.)
'..Waming limit = W1..
'j
- WL = - (p i 2a.) '
Experimental l sigma (all laboratories)'. = ; s, :
n
. x
([1 X )' '
2
.x.
a xj _
N.
's
=
e-3
=N-1 0162639133.'- (49345):
'15
,=
14' l
l s
s:
= :149 pCilliter.
i.
Grand Average; =. GA
.x I
g, :-
GA
=
N 49345 15 i
'GA
= 3290 pCi/ liter
' Normalized deviation from the grand' average = ND' Deviation of the mean from the grand average = D' -
D' = li - GA
= 3120
. 3290 i
D' = -170 pCl/ liter l
r I
lgi~
[,
fa' l
'170 i
=
j-
'206.1' ND' -
-=+-O8 ~
i, 29 i
'l
..t
-