ML20132C235
| ML20132C235 | |
| Person / Time | |
|---|---|
| Site: | 07000133 |
| Issue date: | 11/27/1996 |
| From: | SEVENSON ENVIRONMENTAL SERVICES, INC. |
| To: | |
| Shared Package | |
| ML20132C220 | List: |
| References | |
| PROC-961127, NUDOCS 9612180236 | |
| Download: ML20132C235 (62) | |
Text
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1 Site Characterization, l
Remediation and IIealth and Safety Plan i
For Former CLEVITE CORPORATION SITE East 105 Street, Cleveland, Ohio Submitted To:
l GOULD INC.
Eastlake, Ohio Submitted By:
SEVENSON ENVIRONMENTAL SERVICES, INC.
2749 Lockport Road Niagara Falls, NY 14302 Revised November 27,1996 9612180236 961127 PDR ADOCK 07000133 C
PDR 1
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Former CLEVITE CORPORATION Site l
Table of Contents l
l Section Descriotion fage i
i 1.0 Int rod uct ion........................................
1 2.0 Site Description / Background
............................3 3.0 Characterization / Termination Survey Plan................... 4 4.0 Survey Plan & Procedure............................... 14 5.0 Interpretation of Survey Results.........................
29 6.0 Report 48 7.0 Remediation Plan...................................
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Appendix A -
Health and Safety Plan Appendix B -
NRC May 27,1993 Report Appendix C -
NRC correspondence of:
December 30,1993 January 13,1994 Appendix D -
Applied Health Equipment Calibration Criteria Appendix E -
Survey Data Summaries Appendix F-QC/QA Procedures
1.0.
INTRODUCTION -
The intent of this plan is to present the methods and general sequencing of the activities Sevenson Environmental Services, Inc. proposes to employ in order to remediate the former Clevite Corporation Facility at East 105th Street.
The primary objective of this plan is to provide a site characterization plan, termination survey plan and remediation plan for NRC approval. Once the characterization plan is approved by the NRC, the sequencing of subsequent operations is as follows:
a.
Performance of the site characterization survey; b.
Submittal of the site characterization survey report for NRC approval; c.
Submittal of a revised remedial plan for NRC approval, if amendment of this Plan is required; d.
Site remediation; e.
Submittal of a final survey report; f.
Performance of a confirmatory survey by the NRC; and 1
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g.
Release of the site when confirmatory survey verifies that release requirements have been satisfied.
The remedial action will be performed in a safe, efficient, and economical manner to minimize the potential of human contact with potentially contaminated material by removing this i
material and transporting it to a Low Level Radioactive Disposal Facility. Upon completion of l
this remediation, Sevenson will perform a termination survey employing the protocols of i
j NUREG/CR 5849, " Manual for Conducting Radiological Surveys in Support of License i
i Termination", to show that the site meets the criteria for release for unrestricted use.
It is Sevenson's intent to have the termination survey approved before starting the j
characterization survey so that information obtained during the characterization survey may be used for release and to prevent duplication of survey efforts. Sevenson realizes that data from the characterization survey can be used in the termination survey report only if the area remains undisturbed.
Approval of the characterization and remediation plan by the NRC will operate in lieu of obtaining NRC permits for the remedial work.
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I 2.0.
SITE DESCRIPTION / BACKGROUND i,
2 The former Clevite Corporation Facility is located at 540 East 105th Street, Cleveland, j_
Ohio. This site is presently owned by Neighborhood Progress, Inc.
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Clevite Corporation was a manufacturer of nuclear fuel under an Atomic Energy i
Commission license, including high-enriched uranium fuel for the U.S. Navy and AEC research i
reactors, as well as Thorium products. The company ceased fuel manufacturing in the 1960's.
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/. closecut radiation survey by the licensee was accepted by the AEC, and the license was terminated. The 160,000 square foot building was sold in 1991 to Neighborhood Progress, Inc.,
and has been divided into smaller sections for lease.
On May 27,1993, a Region III (Chicago) radiation specialist performed a radiation survey at the site which had been identified as a potentially contaminated site in an Oak Ridge j
National Laboratory review of former AEC and NRC licenses.
l The survey identified low-level radioactive contamination in some cracks and crevices in the concrete floor of one portion of the building now occupied by a machine shop.
The machine shop area was surveyed because blueprints in the AEC license file identified it as a fuel manufacturing area. Other areas of the building were surveyed on a 3
1 sampling basis, and no contamination was identified. Selected areas outside the building were also i
surveyed, and no contamination was identified.
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i The area of thorium use was never identified. As a consequence all areas of the 1
Nilding and environs will have to be assumed to be contaminated with natural thorium. All areas l
where thorium is present will be decontaminated to thorium guidelines and all other areas will be j
decontaminated to uranium guideline values.
l Based upon its May 27,1993 survey, the NRC concluded that the first floor machine shop and a few assembly areas were not decontaminated to a residual radiation level consistent L
with NRC Guidelines. However, the NRC also concluded these radiation levels do not constitute l
an immediate health and safety problem. Although the NRC believes there is no immediate danger, the NRC believes its measurements exceed NRC limits for unrestricted use.
f 3.0.
CHARACTERIZATION / TERMINATION SURVEY PLAN j
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3.1 Survey Objectives i
The purpose of the final status survey is to demonstrate that the radiological I
cond! tans at the former Clevite Site satisfy the NRC guidelines and that the plant site can be released for unrestricted use. The specific objectives of the survey are to show that:
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A.. Surface Activity of Buildings & Structures l
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Average surface contamination levels are within the allowed levels.
'2.
Small areas of residual activity, known as " hot spots" do not exceed three times the average value. The " hot spot" limit applies to areas I
2 up to 100 cm. The average activity level within the 1 ni area i
containing a " hot spot" must be within the guidehnes.
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3.
Reasonable efforts have been made to clean up removable activity and the removable activity does not exceed 20% of the average surface activity guidelines.
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Exposure rates in occupiable locations are less than 5 R/hr above background. Exposure levels are measured at 1 m from floor and j
2 lower wall surfaces and are averaged over floor areas of 10 m,
c B.
Volume Activity of Soil & Building Materials j
1.
Average radionuclide concentrations are within the authorized 2
value. Averaging is based on a 100 m grid area.
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Reasonable efforts will be made to identify and remove " hot spots" that exceed the average guideline by greater than a factor of the l
square root of (100/A) where A is the area of the hot spot in m l
l squared.
3.
Exposure rates do not exceed 5 R/hr above background at one meter from the surface. Exposure rates may be averaged over 1
2 100m Brid areas. Maximum exposure rates over any discrete area 2
of < 100 m may not exceed 10 R/hr above background.
The above conditions will be demonstrated at a 95% confidence level for each i
survey unit as a whole. The survey data will be used to calculate the total l
l inventory of isotopes on the site.
l 3.2.
Identity of contaminates Based on known licensed operations at the site the isotopes have been identified to be:
U-234 U-235 l
U-238 l
Th-Nat or Th-232 1
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Based on the mixture ofisotopes that may be present, the following guideline values will be used:
3.2.a.
If Thorium is present, i
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average:
1000 dpm/100 cm averaged over 1 m 2
2 maximum:
3000 dpm/100 cm appiied to < 100 cm 2
removable:
200 dpm/100 cm soil contamination 10pCi/gm 3.2.b.
If Uranium only is present:
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average:
5000 dpm/100 cm averaged over 1 m 2
2 maximum:
15,000 dpm/100 cm applied to area < 100 cm removable:
1000 dpm/100 cm 2
i soil contamination guidelines for Enriched uranium is 30 pCi/gm and for.
natural Uranium is 10 pCi/gm Alpha spectroscopy will be used to determine the isotopic ratios for U-234/U-235/U-238.
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.e The thorium limits will be used as the guideline limits for this project. If it is l
determined through isotopic analysis that no thorium exists in a given survey l
area then the uranium limits will be used.
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3.3.
Organization and Resoonsibilities l
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The survey will be performed by a qualified team of Sevenson Environmental l
employees.
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1 hir. Anthony Certo, Site Superintendent.
-l His duties are overall responsibility for work operations.
l Afr. Rory Grube, Radiological Safety Officer / Health Physicist.
e His duties are to supervise and perform radiological monitoring and analysis, review and evaluate radiological surveys, prepare reports.
Afr. Scott Wasmer, Health Physics Technician.
His duties are to perform radiological monitoring, collect environmental samples, assist in report preparation, enforce site safety and health plan.
Alr. Paul Hitcho, CIH, Health and Safety Officer.
His duties are to develop implement and update as appropriate, and enforce the site specific safety health and emergency response plan.
hir. John Davis, CHP, QA/QC.
His duties will be to coordinate all interface requirements during the survey process, ensure that all aspects of the QA is adhered to. In performance of his QA/QC duties, Mr. Davis will be completely independent of other site duties.
Site Supv
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I H&S Rad Safety QA/QC HP Tech i
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3.4.
Training Reauirements l
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i The primary purpose of maintaining training requirements is to ensure that all j
i personnel know and understand radiological controls and that all personnel i
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working on the site are aware of their responsibilities in the area of radiation i
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protection to ensure the safe operation of the site and general safety of the j
l public. The best protective measure available to the site is a highly trained and capable work force that employs proper radiological controls in their work i
environment. Training will meet or exceed all requirements of 10 CFR 19.
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Specific details of the training requirements are presented in Section 10 of the l
Health and Safety Plan. All provided training will be documented by Sevenson l
and certified by recipient.
3.5 Laboratories Analytical services for smears and air work zone air samples will be performed on site by Sevenson. Soil samples and environmental air samples will be analyzed by Controls for Environmental Pollution, Inc., Santa Fe, NM. The QA coordinator will monitor in-house and contractors laboratory services.
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3.6 General Survey Plan This survey plan consists of systematic processes and procedures that have been deemed acceptable by industry standards and the NRC. Table 1 provides a breakdown of activities.
3.7.
Tentative Schedule Upon receipt of notice to proceed, Sevenson shall initiate on-site mobDization, training, etc., as aforementioned. Approximate times for completion are as follows:
Mobilization - 2 days.
Training - all workers will be trained prior to arriving on site with the exception of site specifics. This will take approximately I week.
Radiological surveys for site characterization / termination survey - 3 weeks.
Site remediation - 2 months l
Final survey report - 3 weeks j
s' Demobilization - 2 days 11
r 3.8.
Survey Reoort A report describing the survey procedures and findings will be prepared and 1
submitted to the NRC. The report format and content will follow the recommendations contained in NUREG/CR 5849.
l Appendix E contains the survey data summaries and statistical analysis of the l
data, tables E-1 through E-9 and F-1 and F-2.
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I TABLE 1 OVERVIEW OF MAJOR TASKS AND ACTIVITIES Evaluate contamination potential l
1.
Review operating history with respect to facility use, spills, releases etc.
2.
Identify radionuclides of concern and determine guidelines, j
3.
Classify areas as to "affected" and " unaffected".
Establish grid reference system 1.
Install grids.
2.
Prepare facility survey maps.
l Determine background levels 1.
Measure indoor exposure rates and ambient beta-gamma levels.
2.
Measure outdoor exposure rates.
3.
Collect background soil samples.
Perform direct measurements 1.
Conduct surface scans.
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Determine frequency and locations of measurements to meet criteria.
3.
Conduct surface activity measurements.
4.
Measure exposure rates.
Collect Samples 1.
Determine frequency and locations of sampling to meet criteria.
2.
Collect systematic and special samples.
Analyze Samples l
1.
Count smears and swabs.
2.
Analyze soil, paint, residue and other solid samples for uranium / thorium activity.
Interpret data 1.
Convert data to standard units.
2.
Calculate average levels.
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Compare data with criteria.
4.
Compute total residue activity inventory.
i Prepare report 1.
Construct data tables.
2.
Develop graphics.
3.
Prepare text.
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Submit report to NRC.
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j 4.0 SURVEY PLAN & PROCEDURE 4.1 General Due to the nature of operations conducted at the site, the entire building and surrounding area must be surveyed including the roof of the building. The a
number of samples taken will be determined by the use and previous assessment. The data for areas not disturbed as a result of this survey will be used to support the termination survey of the site.
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4.2 Instrumentation l
Table 2 lists the instrumentation to be used for the survey activities, along with typical parameters and detection sensitivities for the instrumentation and survey technique. The combination ofinstrumentation and technique were chosen to provide a detection sensitivity of 25% or less of the guideline levels.
Sensitivities for scanning techniques are based on movement of the detector over the surface at I detector width per second and use of audible indicators to sense changes in instrument count rate. Experience demonstrates that 1
qualified surveyors can detect the levels listed in Table 2 with a 90%
confidence level. Allinstruments will be calibrated a minimum of once every 6 months, using NIST-traceable standards. Calibration will be for the specific uranium radiation energies expected to be present at the site. Operational and 14
l background checks will be performed at least once each 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> on instrument l
l use. The check source will be Tc99 for Beta and Th-230 for Alpha.
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The basic equations for determining field instrument detection limits are:
Surface Activity Measurement for an integrated measurement over a preset time l
MDA = 2.71 + 4.65 MDA = Activity levelin dpm/100 cm2 A
B=
Background cpm t E.
100; t=
count time in minutes
(
A=
Active probe area in cm j
2 E=
Detector efficiency (1) MDA Surface Activity Measurement of a Ratemeter Instrument 4.65 E-MDA = Activity levelin dpm/100 cm 2
$ 2t, B=
Background cpm A'
t, =
meter time constant l
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E-2 A=
Active probe area in cm
'100' E=
Detector efficiency (2) MDA Spenning MDA l
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2 MDA = Activity level in dpm/100 cm Br =
Background rate l
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- Br E=
Detector efficiency l
MDA =
E
- A/100 A=
Area of probe (3) MDA Scanning i
l Laboratory Analvsis of Wines l
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2.71 + 4.65 /B, t MDA = Activity levelin dpm/100 cm l
2 3fgj _
(t) - (E)
Bg =
Background cpm l
t=
count time in minutes l
E=
Detector efficiency l
(4) MDA l
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Table 2 INSTRUMENTATION FOR RADIOLOGICAL SURVEYS Type of Detector Meter
Background
4n Eff Detector Sensitivity Measurement Surface Activity Ludlum 43-68 Ludlum 2221 4 - 5 cpm 20 %
100 dpm alpha 100 cm2 Window Gas Proportional Surface Activity Beta Ludlum 43-68 Ludlum 2221 150 cpm 48 %
Scan 1250 dpm 100 cm2 Window Direct 165 dpm Gas Proportional Surface Scan Alpha Ludlum 43-65 Ludlum 3 1 - 2 cpm 15 %
80 dpm 50 cm2 Window Ludlum 4 Scintillation Surface Scan Ludlum 44-9 Ludlum 3 20 - 40 cpm 19 %
2000-4000 dpm Beta / Gamma 15.5 cm2 Window Ludlum 4 Pancake Surface Activity Ludlum 43-65 Ludlum 3 1 - 2 cpm 15 %
200 dpm Alpha 50 cm2 Window Ludlum 4 Scintillatior i
Surface Activity Ludlum 44-9 Ludlum 3 20 - 40 cpm 19 %
400-800 dpm Beta / Gamma 15.5 cm2 Window Ludlum 4 Pancake Surface Activity 43-1-1 Ludlum 2224-1 0.2 - 2 cpm a 27%a 14 - 26 dpm a Alpha / Beta / Gamma 140 - 160 cpm py 47%py 163 - 175 dpm py 4
Surface Scan 43-1-1 Ludlum 2224-1 0.2 - 2 cpm a 27%a 2 - 17 dpm a Alpha / Beta / Gamma 140 - 160 cpm py 47%py 1191 - 1361 dpm py Surface Scan Gamma 1 X 1 Nai Ludlum 3-97 7 - 10 uR N/A 4uR t
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Table 2 INSTRUMENTATION FOR RADIOLOGICAL SURVEYS Exposure Rates 1 X 1 Organic Crystal W.B. Johnson 4-5 R N/A 3R Model GSM160 R Meter i
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DETECTOR SENSITIVITY COMPUTATIONS Surface Scan Alpha B = 2 cpm E = 0.15 A = 50 MDA =
3x2 E*
0.15 x 50/100 Static Surface Alpha: B=2 E = 0.15 t, = 0.16 ypj, _4.65 x /2/2 x 0.16 0.15 x 0.5
155 dpm Surface Scan Beta B = 300 E = 0.19 A = 100 MDA
3 x 300 0.19 x 100/100 Pm Static Surface Activity Beta:
yog = 4.65 x V300/2 x 0.016
- 0. i? x 100/100
= 749.35 dpm Surface Activity Integrated Time: B = 300 t=1 MDA = 2.71 + 4.65 /300 x 1 1 x 0.19 x 100/100
= 438 dpm 19
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1 DETECTOR SENSITIVITY COMPUTATIONS Surface Scan Alpha B = 2 cpm E = 0.15 A = 50 MDA =
3x2
= 80 dpm i
0.15 x 50/100 l
l Static Surface Alpha: B=2 E = 0.15 t, = 0.16 ggj _4.65 7/2/2 x 0.16
{
0.15x0.5 PS l
l Surface Scan Beta B = 300 E = 0.19 A = 100 i
MDA =
3 x 300
= 4736.84 dpm 0.19 x 100/100 l
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Static Surface Activity Beta:
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MDA 4.65 x /300/2 x 0.016
= 749.35 dpm 0.19 x 100/100 1
Surface Activity Integrated Time: B = 300 t=1 MDA = 2.71 + 4.65 /300 x 1
= 438 dpm 1 x 0.19 x 100/100 t
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Fisw Diagr m cf STRUCTURAL Fin:1 Status S:rvey 5
- Figure 4.1
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Sec 4.3.1...
Classify Area Reclassify Sec 4.3.3..
o Prepare Surfaces Sec 4.3.1 1
Sec 4'3'*7 Establish Grids 4
1 Prepare Reference Sec 4.3.2...
Drawings 1
Sec 4~'" "
Select Instrumentation
,L.
f Sec 4.3.4"*
l Conduct Surface Scans I
Perform Direct Measurements Sec 4.3.5...
a y Activity y Exposure Rates i
Sec 4.3.5...
".rf rm Removable Actmty Measurements 2
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Perform AdditionalDirect Measurements Furniture, i
Sec 4.3.5...
Ducts, Piping, etc.
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1 Perform Special Sampling.
Sec 4.3.5" Pipes, Ducts, Cracks, Wall i
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Coatings. etc.
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F13w Dirgram cf STRUCTURAL Final Status Survey Figurs 4.1 g
o Evaluate Results Relative Remediate As Necessary Sec 5.5"'"
to Guidlines n
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Guideline values and e
Is Reclassification Sec 5'5"
- YES Conditions Satisfied?
~4 Necessary ?
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$YES Sec5.7"
. Calculate Site Inventory d
I Document Results in Final Status Report l
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Fl:;w Dir: gram cf Sit) Grourds Final Status SIry y-Figure 4.2 Sec 4.3.l...
Classify Area Reclassify L
Sec 4.3.3...
n Prepare Surfaces Sec 4.3.1 e
i Sec 4.3.2"'
Establish Grids 1-1 1
Papam Refemnce l
Sec 4.3.2...
Drawings Sec 4.2...
1 Select Instrumentation 2
L e
i Sec 4.3.4'"
i Conduct Surface Scans l
l Perform Direct Measumments Sec 4.3.5...
1 apy Actmty i
y Exposure Rates 4
a
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Subsurface Activity VE5 Coduct Subsurface
' Possible Surveys if j
Appropriate Ho s
Evaluate Results Relative Remediate As Necessary Sec 5.5....
to Guidlines j
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Guideline values and Is Reclassification vfs
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Se 5.5....
Conditions Satisfied?
Necessary ?
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d WS j'
Sec 5.7""'
Calculate Site Inventory 1
Document Results in Final Sec5.4...
Status Report 22
4.3 Survey Plan 3
4.3.1 Classification By Contamination Potential l
(Refer to Figure 4.1 & 4.2) l i
All areas will not have the same potential for contamination and will not require the same degree of attention to achieve an acceptable degree of confidence that the site satisfies the established release criteria. The two classifications used are affected and unaffected.
Classification will be accomplished by examining records of building use. In general, affected areas will include areas where radioactive material was used or stored or where records indicate spills or other unusual events took place. Included in this classification are adjacent areas to the area of use. A preliminary analysis j
based on prior surveys indicate that the machine shop, including the upper walls and ceiling and hallway adjacent to the machine shop, are affected areas, and all other areas will be unaffected.
Areas identified by scans or direct measurements as exceeding guidelines will l
be reclassified as affected areas and gridded and resurveyed accordingly.
l Refer to figures 4.1 and 4.2 for the decision making process. Those areas l
where the elevated activity is due to fluctuations in background levels will not l
be reclassified. These areas are identified room by room in section 5. This l
decision was based on the type of material and the fact that no alpha l
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contamination existed. It thould be noted that both uranium and thorium are l
i alpha emitters.
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4.3.2.
Gridding and Survey Unit Designation l
l Affected areas will be divided into 100 m' survey units. The flocr l
surfaces and wall surfaces up to 2m in height will be marked offin Im grids.
Ifit is believed that contamination > 25% of the guideline value exists, then upper walls and ceiling will be gridded, i
Unaffected areas will be divided into larger survey units.
Due to the l
complexity of the physical layout of the interior of the building, an on-site i
determination will have to be made as to size. It is planned to limit the survey units to a maximum of 1000 m2. Thirty survey points will be established in each unit.
If necessary, a grid system will be established to facilitate the identification of survey points.
Land areas around the building will be gridded at 10m intervals.
4.3.3.
Surface Preparation 24
The radiations from Th-232 are predominately alpha and beta radiations. Tile and carpet on the floor can shield out all the alpha and a majority of the beta. If a floor covering has been installed since operations i
utilizing radioactive material ceased, the tile at the survey point will have to be removed or the carpet lifted in order to conduct a valid survey. In some i
l cases. grease or paint may have to be removed in order to meet the objectives of the survey.
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4.3.4.
Surface Scanning of Structures r
100% of the floor, wall, and ceilings in affected areas will be scanned for alpha, beta, and gamma radiations, including the upper surfaces of exposed duct work and piping. Activity levels will be recorded on prepared diagrams i
or maps. Scanning speeds will be 1 detector width per second for alpha and i
beta detection and.5m per second for gamma detection. Residual alpha and t
beta activity in excess of 3x the guideline value or external radiation in excess of 2x the guideline value above background at I meter from the surface will be remediated.
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1 In unaffected areas,10% of the floor and lower wall surfaces will be scanned l
and results logged in a prepared diagram or survey map. Scanning speeds will be 1 detector width per second for alpha and beta detection and.5m per second for gamma detection. Grid lines or permanent fixtures will be used for locations. If residual activity in excess of 25% of the guideline values is i
detected, the unit will be recategorized as affected.
Scans will be made of outdoor areas at im above the surface. Ten meter grids will be established for affected areas and 100% of the area will be scanned.
Areas of suspected elevated activity will be sampled and analyzed, and the activity compared with the guideline values. This area will be remediated as required.
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Surface Activity Measurements 4
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Since our instruments cannot go below 25% of the guideline value for 2
beta, systematic measurements will be made at a spacing of im for alpha and t
l beta radiation, and 2 m for gamma radiation. A one minute reading will be taken and recorded in the field log book.. A smear for removable activity will l
be taken at each direct reading location. Q-tips will be used for cracks and i
i holes in the floor for smear tests. If a survey point is determined to have 1
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residual activity in excess of the guideline values, five additional direct 4
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radiation measurements will be made around the original high reading so as to
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j cover an area of 1m. If the weighted average, as described in Sec. 8.5. of 2
. NUREG/CR-5849 is greater than the guideline values, the area will be marked i
for remediation and resurveyed. Cores of the concrete floor and sub soil will l
be cut and analyzed if indications show activity going through cracks in the i
floor. After all survey points in a survey unit are less than the guideline values, a statistical analysis will be performed to insure that sufficient survey points were included in the unit.
Unaffected areas will have a minimum of 30 survey points in each unit, direct readings will be made for fixed and removable radiation. These points will be on all building surfaces, including upper surfaces of exposed duct work and pipes.
If residual activity in excess of 25% of the guideline values is measured, the survey unit will be made an affected area. When the survey of 27
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the unit is completed, a statistical evaluation will be performed to insure sufficient data exists.
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In affected outdoor areas, when scanning has indicated that guideline values have been met, systematic sampling at 4 equidistant locations between the l
center and each grid block corner will be performed. A minimum of 30 data points will be used. For paved surfaces, a measurement similar to that used j
indoors will be used. If indications point out that the activity is below the i
surface, then cores of the paving and subsoil will have to be taken.
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i In unaffected outdoor areas, 30 random sample points will be selected for soil l
sampling and analysis. For pavement, 30 randomly selected locations will be j
analyzed for surface activity.
4.4.
Background Measurements.
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1 Interior background measurements will be made inside the buildings of the l
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Clevite site, having no history of radionuclide use. A series of 8 to 10 4
1 readings will be made on each meter / detector used. The average and 95%
confidence level will be determined for each instrument. Also, a minimum of l
10 locations for area background measurement and sampling will be selected l
within a 0.5 to 10 km radius of the site. Exposure rate measurements will be l
performed using a micro R meter. A background soil sample will be collected.
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This Section describes methods for converting survey data to appropriate units for comparison with guideline values and evaluating data, relative to conditions, established for termination of the license.
5.1.
Data Conversion s
Radiological suney data is obtained in units, such as counts per unit time, which have no intrinsic meaning relative to the guideline values. Therefore, the survey data from field and laboratory measurements are converted to units which will enable comparisons. Standard units used for expressing final status survey findings are:
2 Surface Contamination dpm (disintegrations per minute per 100 cm )
2 100 cm i
e Soil Radionuclide Concentration pCi/g (picocuries per gram)
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Exposure Rate R/h (microroentgens per hour) e I
In performing the conversions, it is necessary to know several factors; these are:
e total integrated counts recorded by the measurement c/m total countrate from an analog (rate) instrument t
time period (minutes) over which the count was recorded B
count during recording period, due only to background levels of radiation B/m background count rate on an analog instrument E
detection efficiency ofinstrument in counts per disintegration 4
2 A
active surface area of the detector in cm M
mass of sample analyzed in grams 2.22 factor to convert a disintegration rate to activity units of picocuries, i.e.
dpm/pCi.
4 These factors are used in the equations in the remainder of Section 5.1.
5.1.1.
Surface Activity 30 4
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A measurement for surface activity is performed over an area, represented by the sensitive surface area of the detector. If the instrument display is in count rate, i.e.
counts per minute, the conversion to dpm/100 cm' is performed by:
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dom (c/m - B/m) [100',
=
2 L
100 cm E
\\ AI (5-1) l For a technique using an integrated count on a digital instrument, the conversion is:
l dpm (c - B) 100' j
=
j 100 cm t*E A4 (5-2) 2 i
l l
The level of removable activity collected by a smear is calculated in the same manner, except, the detector area correction factor,100. is dropped from the equation because the smear is i
A performed over a 100 cm area and the detector area
-f 2
correction is usually considered when determining the efficiency, leaving:
l dpm (c - B)
=
100 cm2 t*E (5-3) l i
31 l
w a
5.1.2 Soll Radionuclide Concentration To determine the radionuclide concentration in soil in units of pCi/g, the calculation t
performed is:
pCi/g =
(c-B) t
- E
- 2.22
- M (5-4)
If the analytical procedure includes a wet chemistry separation, it will also be necessary to correct for the fractional recovery (R), determined by a spike or tracer added to the sample.
pCi/g =
(c-B) t
- E
- 2.22
- M
- R (5-5) 5.1.3.
Exposure Rate If an instrument such as a pressurized ionization chamber or a " micro-R" meter is used j
for measuring exposure rate, the instrument reading will be directly in the desired exposure rate units of uR/h. A gamma scintillation or GM detector with a count rate or digital scaling instrument provides data in units of counts per minute or per some preset time, respectively. Conversion to R/h is accomplished, using calibration factors developed for the specific instrument and survey site. The background exposure rate is then subtracted from the total to determine the net level, attributed to residual activity from licensed operations. This net level is compared with the guideline value.
R/h =
c/m or c
(5-6) cLa cLm
. pR/h.
. pR/h.
- Site Specific Calibration Factor for Detector 5.2.
Measurement Uncertainty Each reported value will include an assessment of its uncertainty. The rate of radioactive decay is not constant with time and is therefore described by a Poission probability distribution. Based on such a distribution, the best estimate of the standard deviation (s) on a number of counts (c) is the square root of the counts, i.e.
32 l
l l
f s = (c I
.(5-7) l i
and the standard deviation in a count rate over time (t) is therefore:
1 1
O I
- r
- 7 (5-8) l l
l l
For the majority of measurements conducted during a final status survey, the number l
of counts due only to background will be a significant portion of the total count. The background also has an uncertainty associated with it which is taken into consideration by:
c B
(5-9) 3=
3 -+p l
s r
I where to is the time period over which the background count was determined.
The standard deviation or uncertainty in the count or count rate will be converted to the same standard units used to express the measurement value by use of the equations provided in Section 5.1. The uncertainty will be given at the 95% confidence level which requires multiplying the standard deviation value by a factor of 1.96.
5.3.
Minimum Detectable Activity Less than or equal to minimum detectable activity (MDA) levels will be reported but will only be used for averaging site activity levels when the value for (MDA) < 10%
of the guideline value. For all other calculations, actual values will be used.
)
i 33
5.4.
Data Presentation Format All final status survey data will be presented in the format of NUREG/CR-5849 l
APPENDIX D.
l l
l I
j 5.5.
Comparison with Guideline Values l
l 5.5.1 Removable Activity l
l Data for removable activity levels will be compared directly to the guideline values.
l The limit for removable activity is 20% of the guideline value for total surface activity.
l If that level is exceeded, remediation and resurvey will be necessary.
I l
5.5.2.
Elevated Areas of Activity i
Levels of residual activity, i.e. elevated areas, which exceed the guideline value, are initially compared directly with the guideline.
1 Buildings or Structures e
The limit for maximum activity on a building or structure surface is three times 2
the guideline value, when averaged over an area of 100 cm or less. Residual activity exceeding this limit will be remediated and follow-up surveys performed. Areas of elevated activity between one and three times the guideline value will be tested to assure that the average surface activity level 2
within a contiguous 1 m area containing the elevated area is less than the guideline value.
To evaluate whether this averaging condition is satisfied, additional measurements will be performed, and the activity level and areal extent of the 2
elevated area will be determined. The average (weighted average) in the 1 m area will then calculated, taking into consideration the relative fraction of the 2
I m occupied by the elevated area (s), using the relationship:
n n,
n, l
( = 1 {, r, 1 - { A, + { y,A, (5-10) l "si=1 k=1 k=1 l
where l
l x, =
weighted mean including elevated area (s) 34 i
\\.
l '.,
xi =
systematic and random measurements at point i i
n, =
number of systematic and random measurements l
yg =
elevated area activity in area k 2
A, =
fraction of 1 m occupied by elevated area k l
ng ='
number of elevated areas.
e soil The limit for soil activity at any location is three times the average guideline value. Residual activity exceeding this level will be remediated and follow-up survey performed. Areas of elevated activity between one and three times the guideline value will be tested to assure that the average concentration is less that (100/A)"2 times the guideline value, where A is the area of the elevated 2
activity in m. Levels exceeding this limit will be remediated. Ifthis 2
condition is satisfied, the average activity in the 100 m contiguous area
~
containing the region of elevated activity will then be determined to assure that it is within the guideline value. Equation 5-10 is also used for this calculation, 2
1 substituting 100 m for the 1 fn, used when calculating average surface activity.
l 5.5.3 Exposure Rates Exposure rate levels are compared directly with the guideline value. The maximum exposure rate may not exceed two times the guideline value, above background. If the level is above that value, the area will be remediated and resurveyed.
I I
35 I
.c 5.5.4. Calculating Average Levels General surface activity, soil activity, and exposure rate guideline values are average values, above background, established for areas of survey unit surfaces (surface.
2 2
activity),100 m (soil activity and open land exposure rates), and 10 m (indcor exposure rates). To enable comparison of the survey data with those guidelines, the mean (x) of measurements in each of the survey units is calculated using all measurements (n,) within that area:
(5-11) 5.5.5 Comparisons Average levels, calculated following the procedures in Section 5.5.4, are compared with the guideline values and conditions. If the averages exceed the applicable guideline values and/or conditions, further remediation is required and follow-up measurements will be performed to verify the effectiveness of the actions. After the averages satisfy the guideline values and conditions, the results will be further evaluated to determine whether the data each survey unit (i.e. group of contiguous l
grids or regions with the same classification of contamination potential), provides a 95% confidence level that the true mean activity level meets the guidelines.
The test is performed by calculating the average (equation 5-11) and standard deviation of the data for a particular radiological parameter in each survey unit using all measurement locations; the standard deviation is calculated by:
(5-12)
If there are areas of elevated activity in the survey unit, the weighted mean x (equation 2
2 5-10) for each 1 m of building surface, or 100 m ofland, containing an elevated area, will be used as one of the xi s in equations 5-11 and 5-12.
(5-13) where is the 95% confidence level obttined from NUREG/CR-5849 t,,
=
i Appendix B. Table B-1: df (degrees of freedom) is n-1. a is the false positive probability, i.e. the probability that, is less than the guideline value if the true mean activity level is equal to the guideline value.
36
.o is the calculated mean from equation 5-11 x=
i s, =
is the standard deviation from equation (5-12) is the number ofindividual data points used to determine x and s,.
n=
The value of, is compared to the guideline value; if, is less than the guideline, the area being tested meets the guideline at a 95% confidence level. This means that the probability is less than 5% that, will pass the test, when the true mean activity level exceeds the guideline value.
5.6.
Identifying Additional Measurement / Sampling Needs If, calculated in the previous section is greater than Co (NRC guideline value), there are two possibilities. If x.2. Co, a cleanup is required. However, if x < Co, a larger i
sample might be able to demonstrate compliance. The sample mean (x) and standard deviation (s) for a given sample size were calculated in the previous Section using equations 5-11 and 5-12. Using these parameters, the total number of data points (n)
}.
which would be required to demonstrate that the activity level satisfies the guideline value at the desired level of confidence, is determined by:
l 1
j (5-14) where i
number of data points required n
=
I guideline value Co
=
x
=
mean sample standard deviation S,
=
standard normal variables: a is the false positive probability, i.e.
Z, Z.p
=
i i
that, < Co, if the true mean activity is equal to Co, and p is the false negative probability, i.e. that, > Co, if the true mean activity is equal to Co.
NUREG/CR-5849 Table B-2 (Appendix B) has been provided for ease of estimating the total number of data-points required to demonstrate meeting guidelines at a false positive level of 5% and a false negative level of 10%. Subtracting the number of data points already collected (n) from this total calculated number (ni), determines the 37
number of additional measurements or samples which will be required to demonstrate the desired confidence of the data. If this calculation indicates that additional data are needed from a survey unit to demonstrate meeting the guideline, it is recommended that they be collected uniformly over the area, using the same sampling methodology as that used for the first samples. To demonstrate compliance,, is based on all data points; thus additional data are combined with the original data and the acceptance testing repeated. The process of determining additional samples to try to meet the guideline can only be done one time. If the additional samples do not bring p, below the guideline, additional remediation will be required.
5.7.
Calculating Site Inventory l
l The total residual activity is calculated for each radienuclide by determining the mean l
activity for each survey unit, multiplying that mean level by the total surface area or l
soil volume of the unit. The total activity of the site will be determined by summing all l
survey unit activities.
l l
5.8.
Results by Room l
l a.
Basement l
i.
Boiler Room / Entrance - 32 grids greater than or equal to 25% of the l
guideline value of which 7 are greater than or equal to 1000 l
dpm/100cm2 (direct). Elevated readings due to naturally occurring l
radioactive material in structural material. 6 of the seven readings l
greater than 1000 dpm/100cm2 were on brick walls in close areas. These l
readings are due to the natural fluctuations in background. The seventh l
reading greater than 1000 dpm/100cm2 was on a twelve inch tile drain I
pipe. Tile drain pipe has naturally occurring radioactive in it as on site l
sampling has indicated.
l l
b.
South East Wing,1st Floor l
i.
Room # 1 - 118 grids greater than or equal to 25% of the guideline value l
of which 2 are greater than or equal to 1000 dpm/100cm2 (direct). 2 l
grids greater than or equal to 25% of the guideline value of which 1 is l
greater than or equal to 200 dpm/100cm2 (smearable). This room was l
surveyed as an affected area. This room contained four anchor bolt I
holes. The contamination was from a single source and in a limited area.
l The areas above the guideline values will be remediated. The remediated l
areas will be surveyed as well as one adjacent 1 meter grid square.
l ii.
Room # 2 - 219 grids greater than or equal to 25% of the guideline value l
of 1000 dpm/100cm2 (direct).1 grid greater than or equal to 25% of the l
l guideline value of 200 dpm/100cm2 (smearable). This room was l
surveyed as an affected area.
l 38
l l
l iii.
Room # 7-75 grids greater than or equal to 25% of the guideline value l
of which 13 are greater than or equal to 1000 dpm/100cm' (direct).1 l
grid greater than or equal to 25% of the guideline value of 200 l
dpm/100cm2 (smearable). 3 grids were greater than or equal to 3000 l
dpm/100cm2 (direct). This room was surveyed as an affected area. The l
l contamination was under the wall between room # 7 and room # 18. The l
contamination was from a single source and in a limited area. The areas I
above the guideline values will be remediated. The remediated areas will l
be surveyed as well as one adjacent 1 meter grid square.
l iv.
Room # 8 - 15 grids greater than or equal to 25 % of the guideline value l
of 1000 dpm/100cm2 (direct). This is the room where the Dew Pointer l
l was found,20 mrem /hr @ contact with source,2 mrem /hr contact with l
case. This room was surveyed as an affected area. The elevated activity l
l readings are attributed to naturally occurring radioactive materialin the l
structural material. A clay tile pipe contributed to the elevated activity at l
the drain. The Dew Pointer was removed. No further remediation is l
l required.
l v.
Room # 9 - 41 grids greater than or equal to 25% of the guideline value l
of which 11 are greater than or equal to 1000 dpm/100cm2 (direct). 41 l
grids greater than or equal to 25% of the guideline value of which 36 are l
greater than or equal to 200 dpm/100cm2 (smearable).1 grid was greater l
than or equal to 3000 dpm/100cm2 (direct). This room was surveyed as l
an affected area. The contamination in this room was a continuation l
from the hallway. The areas above the guideline values will be l
remediated. The remediated areas will be surveyed as well as one l
adjacent 1 meter grid square.
l vi.
Room # 10 - 7 grids greater than or equal to 25% of the guideline value l
of which 3 are greater than or equal to 1000 dpm/100cm2 (direct). This l
room was surveyed as an affected area. The areas above the guideline l
values will be remediated. The remediated areas will be surveyed as well l
as one adjacent 1 meter grid square.
l vii.
Room # II - 94 grids greater than or equal to 25 % of the guideline value l
of which 3 are greater than or equal to 1000 dpm/100cm2 (direct). This l
room was surveyed as an affected area. TM contamination was found l
under the sliding pocket door from the hah vay. The other elevated l
l activity readings are attributed to naturally occuning radioactive material l
j found in the structural material. The areas above tce guideline values l
will be remediated. The remediated areas will be surveyed as well as one l
adjacent 1 meter grid square.
l viii.
Room # 12 - 24 grids greater than or equal to 25% of the guideline value l
of 1000 dpm/100cm2 (direct). The elevated activity levels are attributed l
l to naturally occurring radioactive material found in the structural l
material. This room was surveyed as an affected area.
l
\\
39 l
ix.
Room # 13 - 47 grids greater than or equal to 25% of the guideline value l
of which 3 are greater than or equal to 1000 dpm/100cm2 (direct). I grid I
was greater than or equal to 3000 dpm/100cm2 (direct). This room was l
surveyed as an affected area. The areas above the guideline values will l
be remediated. The remediated areas will be surveyed as well as one l
adjacent 1 meter grid square.
l Room # 14 - 69 grids greater than or equal to 25% of the guideline value l
x.
of which 2 are greater than or equal to 1000 dpm/100cm2 (direct).1 grid l
was greater than or equal to 3000 dpm/100cm2 (direct). This room was I
surveyed as an affected area. The areas above the guideline values will l
be remediated. The remediated areas will be surveyed as well as one l
adjacent 1 meter grid square.
l xi.
Room # 15 - 1 grid greater than or equal to 25% of the guideline value l
of 1000 dpm/100cm2 (direct). The elevated activity levels are attributed l
to naturally occurring radioactive material found in the structural l
material.
l xii.
Room # 18 - 72 grids greater than or equal to 25% of the guideline value l
of which 28 are greater than or equal to 1000 dpm/100cm2 (direct).1 l
grid greater than or equal to 25% of the guideline value of which 1 is l
greater than or equal to 200 dpm/100cm2 (smearable). 7 grids were l
greater than or equal to 3000 dpm/100cm2 (direct). This room was l
surveyed as an affected area. The contamination in this room was l
isolated to under the wall adjoining room # 7. The areas above the l
guideline values will be remediated. The remediated areas will be j
i surveyed as well as one adjacent 1 meter grid square.
l xiii.
Sections (A. B. C. etcJ - 60 grids greater than or equal to 25% of the l
guideline value of which 15 are greater than or equal to 1000 l
dpm/100cm2 (direct). 5 grids greater than or equal to 25% of the l
guideline value of 200 dpm/100cm2 (smearable). 9 grids were greater l
than or equal to 3000 dpm/100cm2 (direct). The hallway, where it joins l
the west wing, was identified as contaminated above the guideline value l
and was reclassified as affected. The rest of the areas remained l
unaffected and the elevated activity is attributed to naturally occurring i
activity in structural material. The areas above the guideline values will l
be remediated. The remediated areas will be surveyed as well as one l
adjacent 1 meter grid square.
l xiv.
Test Cell-26 grids greater than or equal to 25% of the guideline value l
of which 14 are greater than or equal to 1000 dpm/100cm2 (direct).1 l
grid greater than or equal to 25 % of the guideline value of 200 l
dpm/100cm2 (smearable). 7 grids were greater than or equal to 3000 l
dpm/100cm2 (direct). This room was surveyed as an affected area. This l
room contained contaminated sand. The areas above the guideline values l
will be remediated. The remediated areas will be surveyed as well as one l
40 l
adjacent 1 meter grid square.
l 1
c.
South East Wing,2nd Floor l
i.
Ravf-52 grids greater than or equal to 25% of the guideline value of l
which 1 is greater than or equal to 1000 dpm/100cm2 (direct). All of the i
roof areas exhibited elevated activity levels. Samples from the roof, l
counted on site for informational purposes only, indicated no thorium or l
uranium contamination. A sample sent for uranium and thorium activity l
determination indicated no uranium and thorium. It is therefore believed l
1 that the roof area as a whole is either contaminated with naturally l
occurring radioactive material or from fall out from nuclear testing and l
is beyond the scope of the survey guidelines.
l l
l d.
West Wing,1st Floor l
i.
Weld Shoo - 117 grids greater than or equal to 25% of the guideline l
value of which 8 are greater than or equal to 1000 dpm/100cm2 (direct).
l 3 grids were greater than or equal to 3000 dpm/100cm2 (direct). This l
room was surveyed as an affected area. This room is being used for l
welding with thoriated tungsten rods. This room will be surveyed last l
after clean-up to minimize the time between remediation and final status l
survey. The areas above the guideline values will be remediated. The l
remediated areas will be surveyed as well as one adjacent 1 meter grid l
square.
l ii.
Elevator Entrance - 29 grids greater than or equal to 25 % of the l
guideline value of which 8 are greater than or equal to 1000 l
dpm/100cm2 (direct). The elevated activity levels are attributed to l
naturally occurring radioactive material found in the structural material.
I iii.
Inside Dock Area - 61 grids greater than or equal to 25% of the l
guideline value of which 26 are greater than or equal to 1000 l
dpm/100cm2 (direct). I grid greater than or equal to 25% of the l
guideline value of 200 dpm/100cm2 (smearable). 21 grids were greater l
than or equal to 3000 dpm/100cm2 (direct). This room was surveyed as l
an affected area. The areas above the guideline values will be l
remediated. The remediated areas will be surveyed as well as one l
adjacent I meter grid square.
l iv.
Tin Shed (Outside West Wine) - Found a glass jar of thorium oxide.
l This room was surveyed as an affected area. The jar was removed from l
the area. No further remediation required.
l v.
Hallway - 415 grids greater than or equal to 25% of the guideline value l
of which 82 are greater than or equal to 1000 dpm/100cm2 (direct).11 l
grids greater than or equal to 25% of the guideline value of which 4 are l
greater than or equal to 200 dpm/100cm2 (smearable). 45 grids were l
greater than or equal to 3000 dpm/100cm (direct). This room was l
2 41
s surveyed as an affected area. The areas above the guideline values will l
be remediated. The remediated areas will be surveyed as well as one l
adjacent 1 meter grid square.
l vi.
Stainull-84 grids greater than or equal to 25% of the guideline value l
of which 9 are greater than or equal to 1000 dpm/100cm2 (direct). The l
elevated activity levels are attributed to naturally occurring radioactive l
material found in the structural material.
l vii.
Room # 1 - 28 grids greater than or equal to 25% of the guideline value l
of which 8 are greater than or equal to 1000 dpm/100cm2 (direct). 6 l
grids were greater than or equal to 3000 dpm/100cm2 (direct). This l
room was surveyed as an affected area. The areas above the guideline l
values will be remediated. The remediated areas will be surveyed as well l
l as one adjacent 1 meter grid square.
i viii.
Room # 2 - 46 grids greater than or equal to 25% of the guideline value l
of which 16 are greater than or equal to 1000 dpm/100cm2 (direct).12 l
grids were greater than or equal to 3000 dpm/100.:m2 (direct). This l
j room was surveyed as an affected area. The areas above the guideline l
values will be remediated. The remediated areas will be surveyed as well l
as one adjacent I meter grid square.
l ix.
Room # 3 - 175 grids greater than or equal to 25% of the guideline value l
of which 7 are greater than or equal to 1000 dpm/100cm2 (direct). The l
elevated activity levels are attributed to naturally occurring radioactive l
material found in the structural material.
l x.
Room # 4 - 65 grids greater than or equal to 25% of the guideline value l
of which 8 are greater than or equal to 1000 dpm/100cm2 (direct). The l
4 elevated activity levels are attributed to naturally occurring radioactive l
material found in the structural material.
l xi.
Room # 5 - 30 grids greater than or equal to 25% of the guideline value l
of which 27 are greater than or equal to 1000 dpm/100cm2 (direct). 4 l
grids greater than or equal to 25 % of the guideline value of 200 l
dpm/100cm2 (smearable). 23 grids were greater than or equal to 3000 l
dpm/100cm2 (direct). This room was surveyed as an affected area. The l
areas above the guideline values will be remediated. The remediated l
areas will be surveyed as well as one adjacent 1 meter grid square.
l xii.
Room # 6 - 124 grids greater than or equal to 25% of the guideline value l
~
of which 14 are greater than or equal to 1000 dpm/100cm2 (direct). 6 l
grids were greater than or equal to 3000 dpm/100cm2 (direct). This I
room was surveyed as an affected area. The areas above the guideline l
values will be remediated. The remediated areas will be surveyed as well l
as one adjacent 1 meter grid square.
l xiii.
Room # 7-140 grids greater than or equal to 25% of the guideline value l
of which 25 are greater than or equal to 1000 dpm/100cm2 (direct). 3 l
grids were greater than or equal to 3000 dpm/100cm2 (direct). This l
42
s room was surveyed as an affected area. The areas above the guideline l
values will be remediated. The remediated areas will be surveyed as well l
as one adjacent 1 meter grid square.
l xiv.
Room # 8 - 162 grids greater than or equal to 25% of the guideline value l
of 1000 dpm/100cm2 (direct). The elevated activity levels are attributed l
to naturally occurring radioactive material found in the structural l
material.
l xv.
Room # 9-14 grids greater than or equal to 25% of the guideline value l
of 1000 dpm/100cm2 (direct). The elevated activity levels are attributed l
to naturally occurring radioactive material found in the structural 1
material.
l xvi.
Room # 10 - 39 grids greater than or equal to 25% of the guideline value I
of 1000 dpm/100cm2 (direct). The elevated activity levels are attributed l
to naturally occurring radioactive material found in the structural l
material.
l xvii.
Room # // - 134 grids greater than or equal to 25% of the guideline l
value of 1000 dpm/100cm2 (direct). The elevated activity levels are l
attributed to naturally occurring radioactive material found in the l
structural material.
l xviii. Room # 12 - 25 grids greater than or equal to 25% of the guideline value l
of 1000 dpm/100cm2 (direct). The elevated activity levels are attributed I
to naturally occurring radioactive material found in the structural l
material.
I xix.
Room # 13 - 43 grids greater than or equal to 25% of the guideline value l
of 1000 dpm/100cm2 (direct). The elevated activity levels are attributed l
to naturally occurring radioactive material found in the structural I
material.
l xx.
Room # 14 - 134 grids greater than or equal to 25% of the guideline l
value of which 3 are greater than or equal to 1000 dpm/100cm2 (direct).
l This room was surveyed as an affected area. The areas above the l
guideline values will be remediated. The remediated areas will be l
surveyed as well as one adjacent 1 meter grid square.
l xxi.
Room # 15 - 164 grids greater than or equal to 25% of the guideline l
value of which 61 are greater than or equal to 1000 dpm/100cm2 l
(direct). 27 grids were greater than or equal to 3000 dpm/100cm2 l
(direct). This room was surveyed as an affected area. The areas above l
the guideline values will be remediated. The remediated areas will be l
surveyed as wall as one adjacent I meter grid square.
l xxii.
Room # 16 - 577 grids greater than or equal to 25% of the guideline l
value of which 182 are greater than or equal to 1000 dpm/100cm2 l
(direct). 28 grids greater than or equal to 25% of the guideline value of l
which 16 are greater than or equal to 200 dpm/100cm2 (smearable). 93 l
grids were greater than or equal to 3000 dpm/100cm2 (direct). Furnace l
43
in room was used for smelting depleted uranium. This room was l
surveyed as an affected area. The areas above the guideline values will l
be remediated. The remediated areas will be surveyed as well as one l
adjacent 1 meter grid square.
l xxiii. Room # 17-61 grids greater than or equal to 25% of the guideline value l
of 1000 dpm/100cm2 (direct). The elevated activity levels are attributed l
to naturally occurring radioactive material found in the structural l
material.
I xxiv. Room # 18 - 37 grids greater than or equal to 25% of the guideline value l
of which 1 is greater than or equal to 1000 dpm/100cm2 (direct). I grid l
was greater than or equal to 3000 dpm/100cm2 (direct). This room was l
surveyed as an affected area. The areas above the guideline values will l
be remediated. The remediated areas will be surveyed as well as one l
adjacent 1 meter grid square.
l xxv.
Room # 19 - 23 grids greater than or equal to 25% of the guideline value l
of which 2 are greater than or equal to 1000 dpm/100cm2 (direct). The l
elevated activity levels are attributed to naturally occurring radioactive l
material found in the structural material.
l xxvi. Room # 20 - 100 grids greater than or equal to 25% of the guideline l
value of 1000 dpm/100cm2 (direct). The elevated activity levels are l
attributed to naturally occurring radioactive material found in the l
structural material.
l l
e.
West Wing 2nd Floor l
i.
Sections /A. B. c. etc.1 - 36 grids greater than or equal to 25% of the l
guideline value of which 2 are greater than or equal to 1000 l
dpm/100cm2 (direct). The elevated activity levels are attributed to l
naturally occurring radioactive material found in the structural material.
l l
f.
West Wing 3rd Floor l
i.
Sections /A. B. C. etc.J - 32 grids greater than or equal to 25% of the l
guideline value of which 3 are greater than or equal to 1000 l
dpm/100cm2 (direct). The elevated activity levels are attributed to l
naturally occurring radioactive material found in the structural material.
l Areas of particular interest were the bathrooms. Drain pipes in the l
bathrooms are made of tile pipe. The drains are contained in brick walls l
of which one is covered by glazed tile (glazed tile had the highest l
background).
l l
g.
West Wing 4th Floor l
i.
Roof-115 grids greater than or equal to 25% of the guideline value of l
which 6 are greater than or equal to 1000 dpm/100cm2 (direct). 2 grids l
greater than or equal to 25% of the guideline value of which 1 is greater l
44
than or equal to 200 dpm/100cm2 (smearable). 2 grids were greater than l
or equal to 3000 dpm/100cm2 (direct). All of the roof areas exhibited l
elevated activity levels. Samples from the roof, counted on site for l
informational purposes only, indicated no thorium or uranium l
contamination. A sample sent for uranium and thorium activity l
determination indicated no uranium and thorium. It is therefore believed I
that the roof area as a whole is either contaminated with naturally l
occurring radioactive material or from fall out from nuclear testing and l
is beyond the scope of the survey guidelines. The exhaust duct fan was l
located on the 4th floor roof and was the source of contamination on the l
roof. The location where the fan had been was surveyed as affected.
l ii.
Sections /A. B. C. etc. ) - 15 grids greater than or equ2.1 to 25% of the l
guideline value of which 3 are greater than or equal to 1000 l
dpm/100cm2 (direct). The elevated activity levels are attributed to l
naturally occurring radioactive material found in the structural material.
l l
h.
North East Wing ist Floor l
i.
CAMPS Room - 41 grids indicate greater than or equal to 25% of the l
guideline value of 1000 dpm/100cm2 (direct). The elevated activity l
levels are attributed to naturally occurring radioactive material found in l
the structural material. It should be noted that the CAMPS area was l
constructed in the mid sixties. Background fluctuations on construction 1
material were similar to those found through out the rest of the facility l
supporting the argument that many of the areas with elevated readings l
are due to naturally occurring radioactive material found in the structural l
material.
l ii.
Sections (A. B. C. etc.) - 74 grids greater than or equal to 25 % of the l
guideline value of which 5 are greater than or equal to 1000 l
dpm/100cm2 (direct). The elevated activity levels are attributed to l
naturally occurring radioactive material found in the structural material.
l l
i.
North East Wing 2nd Floor l
i.
Grid Seal noraee area. Owner opened a sealed glass case containing l
uranium powder spilling the contents. He then used a standard vacuum l
cleaner to cleanup the spilled powder. Sevenson was requested by the l
owner to survey the area. I grid was greater than or equal to 3000 l
dpm/100cm2 (direct). This room was surveyed as an affected area. The l
areas above the guideline values will be remediated. The remediated l
areas will be surveyed as well as one adjacent 1 meter grid square.
l ii.
CAMPS Room - 27 grids greater than or equal to 25% of the guideline l
value of 1000 dpm/100cm2 (direct). The elevated activity levels are l
attributed to naturally occurring radioactive material found in the l
structural material.
l 45
i iii.
Eccl-62 grids greater than or equal to 25% of the guideline value of l
which 7 are greater than or equal to 1000 dpm/100cm2 (direct). All of l
the roof areas exhibited elevated activity levels. Samples from the roof, l
counted on site for informational purposes only, indicated no thorium or l
uranium contamination. A sample sent for uranium and thorium activity l
determination indicated no uranium and thorium. It is therefore believed l
that the roof area as a whole is either contaminated with naturally l
occurring radioactive material or from fall out from nuclear testing and l
is beyond the scope of the survey guidelines.
l iv.
Sections M. B. C. etel - 66 grids greater than or equal to 25 % of the l
guideline value of which 2 are greater than or equal to 1000 l
dpm/100cm2 (direct). 2 grids greater than or equal to 25% of the l
guideline value of which 1 is greater than or equal to 200 dpm/100cm2 l
(smearable). These areas were primarily in the grid seal room. The l
j elevated activity levels are attributed to naturally occurring radioactive l
material found in the structural material.
l l
.].
North West Wing 1st Floor l
i.
Corner - 18 gr:ds greater than or equal to 25% of the guideline value of l
which 1 is greater than or equal to 1000 dpm/100cm2 (direct). The l
elevated activity levels are attributed to naturally occurring radioactive l
material found in the structural material.
l ii.
Ecef-30 grids greater than or equal to 25% of the guideline value of l
which 5 are greater than or equal to 1000 dpm/100cm2 (direct). All of l
the roof areas exhibited elevated activity levels. Samples from the roof, l
counted on site for informational purposes only, indicated no thorium or l
uranium contamination. A sample sent for uranium and thorium activity l
determination indicated no uranium and thorium. It is therefore believed l
that the roof area as a whole is either contaminated with naturally l
occurring radioactive material or from fall out from nuclear testing and l
is beyond the scope of the survey guidelines.
l l
5.9.
Characterization / Final Status Survey Results l
l Characterization survey information will be used with final status survey information to l
complete a Final Status Survey. Characterization survey results from areas that were l
not remediated and were not treated as affected will be added to survey results from l
areas that were treated as affected and remediated. Areas that were treated as affected l
but contained no activity above the guideline values due to other than naturally l
occurring radioactive material will be added to the final status survey information.
l Areas where the averaging survey proved no activity above the guideline values will be l
added to the final status survey. Where the final survey data overlaps the l
characterization survey data the final survey data taken after remediation will be used, l
46
~..--_
a however, all of the data will be presented. The Characterization Survey Data will be l
resubmitted with the Final Status Survey taken after remediation to complete one l
document that shows all areas of the site are remediated below the guideline values.
l The same format as used in the Characterization Report will be used for statistical l
interpretation and evaluation. This information was submitted in the format suggested l
l l
i 5.10. QC/QA
[
l i
See Appendix F for the procedures used to ensure the validity of the characterization l
and final survey data.
l l
5.11. Determining Number of Background Data Points l
l For the purposes of this manual, if the average of air background is < 10% of the l
guideline value, then background will be considered to be insignificant relative to the l
l guideline. If the average is > 10% of the guideline values, then additional l
1 measurements will have to be made to insure that the average value is representative.
The number of measurement required is calculated in the followmg manner:
(5-15) where number of background measurements required n
=
a mean ofinitial background measurements x3
=
Standard deviation of initial background measurements s,
=
til
,5.5 5,,
t statistic for 95.5% confidence at df=n-1 degrees of freedom, where n is the
=
number of initial background data points.
NUREG/CR-5849, Table B-1 (Appendix B) contains a list of values for the t u tatistic 9
s at various degrees of freedom. Subtracting the number of data points already collected (n) from this total calculated number (n ) determines the number of additional a
measurements or samples which will be required to demonstrate the desired confidence of the data. If this calculation indicates that additional background data are needed, the measurements will be collected uniformly over the area, using the same sampling methodology as that used for the initial samples. The average background is then recalculated using all data points.
I 47
If the value of the upper bound is < 10% of the guideline value, it can be assumed that variations in background will be insignificant. If this value is greater than 10%, then additional samples for background will have to be taken to insure that the average mean represents the true mean value within 20 %
at the 95% confidence level. The number of samples needed to demonstrate acceptance will be determined using sec. 8.7 of NUREG/CR-5849.
4.5 Samole Analysis Smears and swabs for removable contamination will be analyzed for gross J
alpha, gross beta activity. Soil, sediment, gravel, roofing material, and other large volume samples will be analyzed for Thorium / Uranium by Alpha spectroscopy; total thorium will be calculated on the basis of previously determined (Section 3.2) isotopic activity ratios for this site. Activity will be calculated for each specific isotope.
Samples of paint, residue, and other samples of small volume will be analyzed for Thorium / Uranium by wet chemical separation and alpha spectroscopy.
Laboratory chain-of-custody procedures will be observed for all sample analyses.
5.0 INTERPRETATION OF SURVEY RESULTS 29
-. _.... - - - -... ~ -.
6.0 REPORT i
i j
A report characterizing the site will be submitted to the NRC before remediation work 4
j commences. This report will summarize all data in tables. Measurement and sample locations will be shown on scaled drawings. Detailed remediation plans will be
.(
submitted based on the characterization survey.
,l A report, describing the procedures and finding of the final status survey will be j
prepared and submitted to the NRC. Data will be summarized in tables. Measurement t
3 and sampling locations will be shown on scale drawings.
i S
7.0 REMEDIATION PLAN i
7.1, Premobilization Prior to mobilization, the characterization and remediation plans presented herein will require approval by the NRC. Once approval is granted, Sevenson will commence mobilization activities.
48
e 7.2.
Mobilization Upon receipt of the Notice to Proceed, Sevenson will mobilize to the site. Site mobilization includes moving men and equipment to the site in preparation of performing the characterization surveys. All workmen who will perform remedial activities will have undergone baseline physicals and OSHA and site-specific training.
7.3.
Site Remediation After authorization to proceed has been given by NRC the remediation phase of the contract will begin.
Work will consist of " hand" excavation / chipping methods. Identified areas will be chipped using hammers, chisels, small electrically operated chipping guns or l
walk behind floor scabblers. Reasonable effort will be made to identify, l
evaluate, and remove areas of residual activity exceeding the guideline values.
Reasonable efforts will be made to clean up removable activity and removable 2
activity in any 100 cm area will not exceed 20% of the average surface activity guideline value. During all chipping operations, HEPA vacuums will be utilized to collect all dust and particles. The Health Physicist Technician will be present during all remedial activities to insure dust migration does not occur as 49
e well as determining remedial limits by radiological survey. Contaminated materials collected in the HEPA vacuum will be placed in DOT-approved 55-gallon drums in preparation for transport to a licensed disposal facility.
Remediation will occur after normal working hours (e.g. second shift) so that normal plant operation will not be affected. When remediation is completed and the NRC has performed a confirmatory survey, site restoration will commence. Remediated areas will be cleaned, then restored to their original condition. Restoration will primarily consist of applying " flash patch" concrete to disturbed floor areas and paint " touch-up". Equipment and materials that can be decontaminated will be. Decontamination water will be placed in properly labeled 55-gallon drums for proper filtering or disposal. Personnel and equipment decontamination procedures are discussed in the Health and Safety Plan. Sevenson acknowledges that the NRC reserves comments on this section.
7.4.
ALARA l
a.
Man-Rem Estimates l
1.
Mobilization - 0.000 man-rem l
2.
Training - 0.000 man-rem l
3.
Characterization / Averaging Survey - 0.030 man-rem l
4.
Site Remediation - 0.040 man-rem l
5.
Final Survey - 0.000 man-rem l
6.
Demobilization - 0.000 man-rem l
b.
Administrative Controls will be implemented via radiation work permits, l
50
~. - _ _
o
]
dosimetry program, air sampling program, radiation surveys, prejob l
briefings, and man-rem estimates. Additional controls may be l
implemented if exposure estimates are exceeded.
l l
l c.
Engineering Controls will consist of but are not limited to HEPA l
ventilation, containment enclosures with HEPA ventilation, protective l
l clothing, and postings. Containment enclosures will be seal, inspected l
1 and negative pressure tested prior to commencing any work within the l
l enclosure. Additional controls may be implemented.
l i
7.5.
Iransoortation and Disoosal l
I Sevenson anticipates approximately two (2) 55-gallon drums of material may be l
collected (15 Cubic Feet t) from the remedial activities dependent upon results l
of the site characterization surveys. The centrolled material will be placed in l
DOT-approved containers (drums) in preparation of transportation and disposal.
l A licensed hauler will be utilized to transport this material to a facility permitted i
to accept this material.
Wastes shipped to the Low-Level Radioactive Waste Disposal Facility (LLWDF) will meet all of the waste acceptance criteria (WAC) established to achieve conformance with the license of the facility. Sevenson will determine in advance how to package, mark, store, manifest and ship the wastes. Wastes being shipped will meet or exceed federal regulations and requirements.
51
e i
4 l
The waste will be properly manifested, then shipped to the disposal facility.
I-1 The selected disposal facility will be submitted to Gould Inc. prior to disposal.
l 7.6.
Demobilization
[
t Once all remedial activities are complete, Sevenson will demobilize. All men and equipment will be removed from the site. The site will be left in its original, or better, condition.
1 i
j 1
1 l
52
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t APPENDIX F QC/QA PROCEDURES 1
)
,o e
BACKGROUND AND SOURCE CHECKS 1.
Initial background levels will be established before work commences per section 5.8 of the manual.
l 2.
A daily background reading should be made. This reading should fall with in the limits l
established for background. Ifit is higher there is a possibility the detector may be contaminated or meter is not functioning properly.
J 3.
The detection efficiency of the detector should be established initially by taking a series of ten counts and determining the average and the standard deviation at the 95% confidence l
level.
4.
A daily source check should be made of the instrument. The value should fall within the l
established limits. Ifit doesn't, check counting gas, high voltage. Compare against similar j
detector. If comparison fails, send off for repair.
i l
l
BUILDING SCAN SURVEY 1.
Select the proper instrument from those listed in Table 2.
2.
Obtain the proper data sheets.
3.
Fillin the heading on the data sheet.
- 4. A. Affected Areas Scan 100% of the floor and lower walls in affected areas. Ifit is believed that contamination levels on the upper walls and ceilings are less than 25% of the guideline a minimum of 30 measurement locations on each surface should be selected. If contamination levels are greater than 25% of the guideline value all surfaces shall receive a 100% survey. Record elevated locations of radioactivity.
1 B. Unaffected Areas Scan 10% of the floor and lower wall surfaces of unaffected areas using a grid system.
5.
Scan speeds will be one detector width per second for beta and alpha particles and 0.5m/sec for gamma radiation. The detector should be no more than 2 cm off the floor for beta detection and no more than I cm for alpha detection. The gamma probe will be held at the waist.
6.
Locations of elevated radiation will be noted for further investigation.
~
,o e
AVERAGING SURVEY 1.
Select the proper instruments from the 'e~ s. Mc ". Ensure that the background and source checks have been done.
2.
Obtain the proper survey sheets.
3.
Fillin the data sheet heading.
4.
Determine the area of the elevated reading and record the average activity contained in the area. Take five direct readings in the one meter area that contains the elevated reading and record on the form.
5.
Repeat for each elevated reading in the survey unit.
6.
Turn in the forms to the survey coordinator.
BUILDING DIRECT MEASUREMENT AND REMOVABLE CONTAMINATION SURVEY 1.
Select the proper instruments from those listed in table 2. Check to see if backgrounds and source checks have been done.
2.
Obtain the proper survey data sheets.
3.
Compise the survey information at the top of the form.
- 4. A. Affected Area Since the meter used for the beta scanning sumey has an MDA greater than 25% of the guide line the suwey will be done at one meter intervals on the floor and lower wall surfaces and at all locations determined to have elevated levels of activity from the scan survey. A direct measurement on ceilings and upper wall surfaces should be made for each 20 m: of surface area. A scan of each selected location should be made to identify any locations of elevated activity.
B.
Unaffected Area Thirty or 1 per 50 m direct measurement points, which ever is greater, should be selected 2
in the unaffected area. All surfaces in the survey unit should be included in the total area.
5.
Take a one minute count at each location and record the reading.
6.
Take a 100 cm2 wipe at each location of the direct survey using moderate pressure. Place the wipe in an envelope labeled with the proper location. If cracks or bolt holes are present use a Q-Tip to obtain a wipe.
7.
Insure that the forms have been completed and turn them and the wipes in to the survey coordinator.
l
e DATA EVALUATION, AFFECTED AREAS For each survey unit file fill out the attached data summary sheet and insert it into the front of the file when it is completed.
CHECK affected Area Surveys for:
1, Completeness of data.
2.
Do elevated areas of activity exceed 3 x guideline ? If so tag file with red tag indicating
- remediations is needed.
3.
If elevated areas of activity fall between one and three guideline values tag the file with a blue tag indicating an averaging survey is required.
4.
If external gamma readings are greater than b2 x guidelines tag file with red flag for remediation.
5.
If removable contamination levels are 0.2 x guideline tag with a red tag for remediation.
6 If all the survey points meet the guideline criteria determine the average activity for the survey unit using eq.5.ll from the manual.
l 7.
Compare the calculated average value to the guideline using eqs. 5.12 & 5.13.
8.
If the value for g is less than the guideline value the survey unit being tested meets the guideline criteria at a 95% C.L. The file will be tagged with a green flag.
9.
If y is greater than the guideline and the average activity level for the survey unit is greater than the guideline tag the file with a red tag.
10.
If the average activity of the survey unit is less than the guideline a larger sample may demonstrate compliance. If a larger sample is required the number of samples to be taken i
may be determined by eq. 5.14. Tag the file with a yellow flag to indicate additional sampling is required. If after sampling the activity levels cannot meet the guideline criteria tag the file with a red tag for remediation.
12.
If the survey unit meets the criteria in step 8 above calculate the radioactive inventory for the survey unit.
1
DATA EVALUATION, UNAFFECTED AREAS For each survey unit file fill out the attached data surnmary sheet and insert it into the front of the file when it is com;'leted.
CHECK unaffected A/ea Surveys for:
1.
Completeness of data.
2.
Do elevated area of activity exceed 0.25 x guideline ? If so reclassify unit as affected.
3.
If all the survey points meet the guideline criteria determine the average activity for the survey unit using eq.5.11 from the manual.
l 4.
Compare the calculated average value to the guideline using eqs. 5.12 & 5.13.
l 5.
If the value for g is less than the guideline value the survey unit being tested meets the guideline criteria at a 95% C.L. The file will be tagged with a green flag.
i 6.
Ify is greater than the guideline a larger sample may demonstrate compliance. If a larger sample is needed the number of samples needed can be calculated using eq.5.14. Tag the file with a yellow flag to indicate additional sampling.
7.
If upon additional sampling g is still greater than the guideline reclassify the survey unit as affected.
'.g-DATA
SUMMARY
SHEET l
l.
DATE l
2.
SURVEY UNIT 3.
INITIAL CLASSIFICATION i
4.
NUMBER OF SURVEY POINTS > GUIDELINES A. SCANS B. DIRECT SURVEYS i
C. EXTERNAL RADIATION D. REMOVABLE CONTAMINATION 5.
NUMBER OF SURVEY POINTS >l AND <3X GUIDELINES 6.
ARE ALL DATA POINTS LESS THAN THE GUIDELINE VALUES IF THE ANSWER TO 6 IS YES i
7.
WHAT IS THE AVERAGE LEVEL OF CONTAMINATION FOR THE SURVEY i
UNIT 8.
STANDARD DEVIATION FOR SURVEY UNIT 9.
y=
10.
y > GUIDELINE
)
11.
IS THE AVERAGE VALUE > THAN THE GUIDELINE (REMEDIATE).
12.
IS THE AVERAGE VALUE < THAN GUIDELINE (TAKE MORE SAMPLES).
1 13.
HOW MANY MORE SAMPLES MUST BE TAKEN
.