doc_fn: draftord/441/g4417-1.html
DocType: Draft
ID: DOE G 441.7-1
Title: Instrument Calibration for Portable Survey Instruments
Summary:
Org: EH-51
Date_Issue: 01/1997
Date_Close:
VdkVgwKey: draftord-1
Directive: 441.7
Text:
DOE G 441.7-1
(formerly G-10 CFR 835/E1)
January 1997
IMPLEMENTATION GUIDE
For Use With
Title 10, Code of Federal Regulations, Part 835
OCCUPATIONAL RADIATION PROTECTION
INSTRUMENT CALIBRATION
for
PORTABLE SURVEY INSTRUMENTS
ASSISTANT SECRETARY for ENVIRONMENT,
SAFETY and HEALTH
DRAFT GUIDE - FOR REVIEW WITH PROPOSED 10 CFR 835 AMENDMENT
U.S. Department of Energy
IMPLEMENTATION GUIDE
DOE G 441.7-1
INSTRUMENT CALIBRATION
for
PORTABLE SURVEY INSTRUMENTS
CONTENTS Page
I. PURPOSE AND APPLICABILITY. . . . . . . . . . . . . . . . . .1
II. DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . .2
III. DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . .4
IV. IMPLEMENTATION GUIDANCE . . . . . . . . . . . . . . . . . .5
A. Instrument Selection. . . . . . . . . . . . . . . . . . . .5
1. Physical Inspection . . . . . . . . . . . . . . . . . .6
2. General Operation . . . . . . . . . . . . . . . . . . .6
3. Source Tests. . . . . . . . . . . . . . . . . . . . . .6
B. Instrument Calibration. . . . . . . . . . . . . . . . . . .7
1. Precalibration Inspection/Test. . . . . . . . . . . . .7
2. Calibration . . . . . . . . . . . . . . . . . . . . . .7
C. Functional Tests. . . . . . . . . . . . . . . . . . . . . .7
D. Maintenance . . . . . . . . . . . . . . . . . . . . . . . .8
E. Accuracy/Quality Assurance. . . . . . . . . . . . . . . . .8
1. Calibration Standards . . . . . . . . . . . . . . . . .9
2. Reference Radiation Field Requirements. . . . . . . . .9
3. Maintenance of Standards. . . . . . . . . . . . . . . .9
4. Assessments . . . . . . . . . . . . . . . . . . . . . 10
F. Laboratory Documentation. . . . . . . . . . . . . . . . . 10
1. Laboratory Protocol . . . . . . . . . . . . . . . . . 10
2. Laboratory Records. . . . . . . . . . . . . . . . . . 10
3. Instrument Calibration Records. . . . . . . . . . . . 11
4. Instrument Location . . . . . . . . . . . . . . . . . 11
G. Laboratory, Equipment, and Staff. . . . . . . . . . . . . 11
1. Laboratory. . . . . . . . . . . . . . . . . . . . . . 11
2. Instrument Calibration Equipment. . . . . . . . . . . 12
3. Calibration Staff Qualifications. . . . . . . . . . . 13
4. Calibration Staff Training. . . . . . . . . . . . . . 13
V. REFERENCES. . . . . . . . . . . . . . . . . . . . . . . . . 13
VI. SUPPORTING DOCUMENTS. . . . . . . . . . . . . . . . . . . 15
Appendix A
Reference Sources for Calibration . . . . . . . . . . . . . 16
U.S. Department of Energy
IMPLEMENTATION GUIDE
DOE G 441.7-1
INSTRUMENT CALIBRATION
for
PORTABLE SURVEY INSTRUMENTS
I. PURPOSE AND APPLICABILITY
This Implementation Guide (IG) provides an acceptable methodology for establishing and operating a program for
calibrating portable radiological survey instruments that will comply with U.S. Department of Energy (DOE)
requirements specified in Title 10 of the Code of Federal Regulations (CFR), Part 835, Occupational Radiation
Protection (DOE, 1996); hereinafter referred to as 10 CFR 835. For completeness, this IG also identifies
applicable requirements and recommendations contained in secondary documents (American National Standards
Institute (ANSI) Standards, etc.)concerning instrument calibration.
This IG amplifies the regulatory requirements of 10 CFR 835, and provides explanations of the basic requirements
for the calibration of portable survey instrumentation, which are enforceable under the provisions of Sections
223(c) and 234A of the Atomic Energy Act of 1954, as amended (AEC, 1954).
Except for requirements mandated by regulation, contract, or administrative means, the provisions in this IG are
DOE's views on acceptable methods of program implementation and are not mandatory. Conformance with this
guide will, however, create an inference of compliance with the related regulatory requirements. Alternate
methods that are demonstrated to provide an equivalent or better level of protection are acceptable. Contractors are
encouraged to go beyond the minimum requirements and to pursue excellence in their programs.
The word "shall" is used in this IG to designate requirements from 10 CFR 835, DOE Orders, and secondary
documents invoked by them. The requirements of 10 CFR 835 are mandatory except to the extent an exemption
has been granted pursuant to 10 CFR 820, Procedural Rules for DOE Nuclear Activities (DOE, 1993). The words
"should" and "may" are used to represent optional program recommendations and permissible alternatives,
respectively.
This IG does not specifically provide guidance for calibration of installed instruments or low dose rate instruments
(<0.1 mrad/h(1 æGy/hr)); however, some of the included guidance may be applicable to such instrumentation.
This IG also does not provide information on outside interactions (accreditation activities) to maintain
measurement quality.
This IG is applicable to all DOE activities involving occupational exposure to ionizing radiation of DOE
employees and/or DOE-contractor/subcontractor employees.
II. DEFINITIONS
Terms defined in 10 CFR 835 are used in this IG consistent with their regulatory definitions.
acceptance testing: Evaluation or measurement of performance characteristics to verify that certain stated
specifications and contractual requirements are met.
accuracy: The closeness of agreement between the result of a measurement and the true value of the measurand.
adjust: To alter the response by means of a variable, built-in control, such as a potentiometer.
check source: A radioactive source, not necessarily calibrated, used to confirm an acceptable level of instrument
response to radiation exposure.
consistency: Agreement of a measurement's result with the appropriate standard to within a specified level.
consistency demonstration: Use of a comparative device to directly obtain measurement results that are
demonstrated to be sufficiently in agreement with the appropriate standard.
control chart: A plot of the results of a quality control action to record and demonstrate that control is being
maintained within expected statistical variation or to indicate when control is or will be lost without intervention.
decade: A range of values for which the upper value is a power of ten above the lower value.
demonstrated consistency: See "consistency demonstration."
detector: A device or component that produces a measurable response to ionizing radiation.
free-space geometry: A calibration geometry in which the radiation emitted from a bare or collimated source in
air reaches the instrument under calibration with minimal scatter from nearby structures.
functional tests: Tests (often qualitative) to determine that an instrument is operational and capable of performing
its intended function. Such tests include examination of voltage settings, zero settings, response to radiation, etc.
geotropism: A change in the instrument's reading, as its orientation changes, due to gravitational effects.
instrument (radiation detection): A complete system consisting of one or more subassemblies (e.g., detector,
readout, etc.) designed to quantify, when exposed to radiation, one or more characteristics of ionizing radiation or
radioactive material.
instrument calibration: (1) Adjustment of the response of a given instrument to agree with the response of a
standard instrument when both are used to measure the same quantity under the same conditions; or (2)
determination of the response of a given instrument when measuring a physical standard under well-defined
conditions.
laboratory, secondary: A laboratory that maintains and uses a secondary standard as its reference standard.
laboratory, tertiary: A laboratory that maintains and uses a tertiary standard as its reference standard.
portable survey instrument: An instrument intended to be operated while being carried by an individual.
proficiency test: A test of laboratory performance by intercomparison of results obtained from calibration of a
common instrument or radiation source by both the laboratory under evaluation and a reference laboratory.
quality control: Quality assurance actions that achieve and sustain attributes of the material, process, component,
system, or facility in accordance with predetermined requirements.
range: All values between the lower detection limit and the upper measurement limit.
reading: The indicated value of the readout.
readout: The device that conveys visual information regarding the measurement results to the user.
reference field: Radiation fields in which reference values for the field intensity have been established.
reference value: The value of a particular quantity (e.g., exposure rate) that characterizes a laboratory's radiation
field. It is the value to which the reading of an instrument under calibration is compared.
response: The instrument indication produced as a result of some influence.
scale: A sub-range of the total range of measurement.
sensitivity: For a given value of the measured quantity, the ratio of the variation of the observed variable to the
corresponding variation of the measured quantity.
standard (instrument or source):
-- primary (or national) standard: An instrument, source, or other system or device maintained by the
National Institute of Standards and Technology (NIST) (formerly the U.S. National Bureau of Standards).
-- secondary standard: An instrument, source, or other system or device that has been compared directly with a
national standard. Generally reserved for use as a laboratory standard.
-- transfer standard: A physical measurement device, typically a measurement instrument or a radiation source
specifically designed for transport, that has been compared directly or indirectly with a national standard.
This standard may be used as a laboratory standard.
-- tertiary standard: An instrument, source, or other system or device that has been compared directly with a
secondary standard. Generally reserved for use as a laboratory standard.
-- working standard: An instrument, source, or other system or device calibrated by comparison with a
standard other than a National Standard.
test: A procedure whereby the instrument, component, or circuit is evaluated against certain criteria for
satisfactory operation.
traceability: The ability to show, through documentation, that a particular instrument or radiation source has
either been calibrated using the national standard or has been calibrated using a transfer standard in a chain or
echelon of calibrations, ultimately leading to a comparison with the national standard.
type test: A test of one or more production instruments, of the same design, to verify the actual operational
performance characteristics against the expected or advertised performance specifications.
III. DISCUSSION
Neither an emergency response program, nor the ALARA program required by 10 CFR 835.101(c), can be
operated effectively without the appropriate quantity of properly functioning instruments that are appropriate for
measuring the radiation(s) of interest and for operation in the facility's physical environment. In addition to
measuring dose or dose rate to control direct personnel exposure, instruments are used: (1) to control the spread of
contamination (e.g., surface-contamination monitors); and (2) to assess the adequacy of radiological controls (e.g.,
survey meters or environmental monitors).
10 CFR 835.401 requires, in part, that "appropriate" instruments be used to control exposure to radiation and that
these instruments be routinely calibrated, maintained, and tested. American National Standards Institute (ANSI)
Standard N323, Radiation Protection Instrumentation Test and Calibrations (ANSI, 1983) is cited as a mandatory
environment, safety, and health standard in DOE Order 5480.4, Environmental Protection, Safety, and Health
Protection Standards (DOE, 1993). 10 CFR 835 does not address the accuracy of calibrations or measurements.
ANSI N323 requires an accuracy of ñ2% for sources used in calibrations and an accuracy of ñ10% for the
calibrated instruments.
This IG provides guidance for an instrument calibration program that addresses selection (acceptance testing),
calibration, functional testing, maintenance, accuracy/quality assurance, laboratory documentation, facilities,
equipment and staff.
IV. IMPLEMENTATION GUIDANCE
This section describes the basic requirements for conducting an instrument calibration program for the selection,
calibration, routine testing and maintenance of appropriate portable radiation protection instrumentation in support
of DOE operations.
The essential elements of an acceptable portable instrument calibration program are shown below with reference to
10 CFR 835, with additional elements provided in ANSI N323:
-- An instrument calibration program that assures that calibration shall be performed on each instrument at least
annually (10 CFR 835.401 (c)(1) & ANSI N323 (4.7.1));
-- an internal audit program shall be conducted no less frequently than every 36 months (10 CFR 835.102); and
-- a records program shall be established that documents results of maintenance and calibration performed on
instruments used for area monitoring and contamination control (10 CFR 835.703(d)(1)), includes the
maintenance of training records (10 CFR 835.704(a)), documents the type of instrument and changes to the
instrument (10 CFR 835.704(e)), and documents the results of internal audits (10 CFR 835.704(c)).
Further, the following elements should be in place:
-- Detailed procedures covering the calibration of reference sources, support instruments, and field instruments;
-- a method to determine when instruments have been returned out-of-calibration and a method to notify users of
out-of-calibration instruments;
-- properly trained staff with an adequate technical background in instrument calibration; and
-- a dedicated facility that permits calibrations without outside physical interference.
DOE facilities that do not calibrate or test their own portable radiation protection instruments but use such
instruments should establish requirements in their Radiation Protection Program (RPP) with appropriate
Memorandums of Agreement (MOAs) for calibration contractors.
A. Instrument Selection
Instruments shall be selected to measure the types and energies of radiation and the range of radiation dose rates or
surface contamination activities present within the facility (10 CFR 835.401(c)(2)). The instruments shall also be
selected to perform adequately under the environmental and physical conditions that prevail within the facility (10
CFR 835.401(c)(3)). Initial instrument selection shall be made using knowledge of facility radiation types,
energies, anticipated or known ranges, and results of available instrument performance and testing data (vendor or
independent) (10 CFR 835.401(c)(2)). The selection process includes type testing and acceptance testing.
Type Testing
Implementation of a formal instrument qualification (type testing) process in accordance with the relevant
portions of ANSI N42.17A, Performance Specifications for Health Physics Instrumentation - Portable
Instruments for Use In Normal Environmental Conditions (ANSI, 1989a), and ANSI N42.17C, Performance
Specifications for Health Physics Instrumentation - Portable Instruments for Use In Extreme Environmental
Conditions (ANSI, 1989b) is encouraged.
Acceptance Testing
Prior to use, new instruments should be tested against selected specifications of ANSI N42.17A as well as
other specifications as set forth in the purchase agreement. Instruments which do not meet the selected
specifications should not be accepted or used by the facility. Acceptance testing may be based on only a
sample of the instruments purchased for the more difficult-to-test specifications (temperature, energy response,
etc.) but should involve 100% testing for basic specifications.
An acceptance test should consist of: (1) physical inspection; (2) general operations tests; and (3) source tests, and
should precede the instrument calibration. The physical inspections and general operations tests should be
performed on each instrument. The source tests should be performed on a random selection of 10% of the
instrument batch or four instruments, whichever is larger. If one instrument in a sample of a large quantity fails
the test, an additional 10% should be tested. An additional failure would require testing of the entire batch. It
should be noted that temperature response of instruments can vary with components and that large changes can be
observed at temperature extremes that may be in the recommended range for an acceptance test. If operation in
temperature extremes or humidity extremes is anticipated, tests should be performed at the extreme conditions
using an appropriate temperature/humidity chamber.
1. Physical Inspection
This consists of an inspection of instruments for broken parts, loose or missing screws, loose or misaligned knobs,
calibration potentiometers not aligned with access holes, circuit boards not secured, loose wires, loose connectors,
loose components, testing of moving parts and making sure that batteries are fresh and properly installed.
2. General Operation
This consists of switching to check battery condition, verifying the set of the mechanical zero on the meter, testing
the meter zero potentiometer, checking for switching transients, checking for zero drift on the meter, and checking
for light sensitivity, if applicable.
3. Source Tests
These consist of checking source response, geotropism, variability of readings, stability, temperature response,
humidity response, and photon energy response.
B. Instrument Calibration
ANSI N323 and NIST Special Publication 812, Criteria for the Operation of Federally-Owned Secondary
Calibration Laboratories (Ionizing Radiation) (NIST, 1991), have set forth criteria for proper calibration.
A formal instrument calibration (ANSI N323 (4.7.1), 10 CFR 835.401(c)(1)) shall be performed on each instru-
ment at least once every 12 months. The calibration shall (ANSI N323(4)) include a precalibration inspection/test
normally followed by a documented calibration over the entire range of the instrument. Calibration for ranges
where the instrument is not intended to be used need not be conducted, as long as the specific limitations on
instrument use are clearly marked on the instrument. The frequency of calibration should be adjusted to the use of
the instrument and its durability. The National Conference of Standards Laboratories (NCSL), Recommended
Practice RP-1, Establishment and Adjustment of Calibration Intervals (NCSL, 1989) indicates that more frequent
calibrations should be performed when greater than 15% of instruments are returned out of calibration at the
selected calibration frequency (a minimum of annually). This should include all returned instruments that fail a
source check in the field. NCSL/RP-1 also indicates that if, for those instruments for which the calibration cycle
had been more frequent than annual, fewer than 5% are out of calibration, then the cycle may be lengthened but
should not exceed one year.
1. Precalibration Inspection/Test
Upon receipt and prior to any adjustments, instruments should be tested on each scale to determine the present
state of instrument calibration. This is often referred to as an "as found" calibration and should cover the ranges
for which the instrument is expected to be used. If any of the readings are greater than +20% or less than -20% of
the true value, the Radiological Control Organization should be notified. The users of the instrument and their
supervisors should also be notified.
Prior to formal calibration, inspections and tests shall be performed in accordance with ANSI N323(4.1).
2. Calibration
ANSI N323(4) specifies appropriate guidance for calibration under normal and special conditions.
Instruments consisting of separate detectors and count-rate meters/scalers may be calibrated using a suitable pulser
to test/adjust the rate meter/scaler over its entire range. This should be followed by testing the detector at several
selected reference values with an appropriate source or sources. Calibration with the sources should be performed
on the scales most commonly used in the field. In the case of contamination monitors or other energy-dependent
detectors, the calibration should include several sources covering an energy range typical of field conditions. If
existing documentation shows that detectors will operate independently of a specific readout (interchangeability)
and will not cause measurements to exceed the accuracy goal of 10% (recommended goal ñ5%), the detectors and
count-rate meters/scalers may be calibrated independently.
C. Functional Tests
As part of maintaining instrument calibration, instruments shall be routinely tested for operability (e.g., source
checks, battery tests, etc.) (10 CFR 835.401(c)(4)). This may require detailed ANSI N42.17 testing or simple
functional tests performed during routine calibrations (ANSI N323(3)). During use in the field, instruments shall
be tested frequently with a check source to ensure that the readings remain within prescribed limits, as required by
10 CFR 835.401(c)(4) and ANSI N323(4.6).
The routine functional tests should be detailed in the instrument-use procedures and should include, as a
minimum: general condition; battery condition; verification of calibration; background readings; and other tests
(high voltage, zero setting, alarm functions, etc.) as applicable to the instrument. Functional tests also include the
response check and source check. The performance of field tests should be appropriately documented.
Instrument response should be checked prior to each use when they are used on an intermittent basis and daily
during continuous use. Readings should be taken on each scale or decade used during normal operations (ANSI
N323(4.6)). The operator should establish a reference reading for the check source immediately after calibration or
upon receipt in the field. If reference sources are at fixed locations in the field, the reference readings should be
established immediately after the instrument is delivered to the field. The test readings for the check source shall
(ANSI N323(4.6)) be within ñ20% of the reference reading. If the reading is outside of this range, the instrument
should be taken out of service and returned for recalibration and testing.
D. Maintenance
Preventive maintenance shall be performed periodically (at least annually) to ensure that the instruments continue
to meet the required accuracy for field measurements (10 CFR 835.401(c)(1)). Certain tests should be repeated
because aging or replacement of components may affect the instrument's performance. Tests that should be
repeated at a frequency determined by the facility, or after maintenance that may affect performance, are identified
in ANSI N323(3).
All preventive and corrective maintenance should be performed using components and procedural recommenda-
tions at least as stringent as those specified by the manufacturer of the instrument. If the manufacturer does not
provide routine maintenance procedures, a procedure should be written and approved by staff and management in
the organization performing the maintenance. Replacement components should be manufacturer-approved or
equivalent. Repairs made using components which are not technically equivalent constitute an instrument
modification and should be considered to render invalid any type tests made on the instrument model as applied to
the specific instrument. Instruments that have been modified for special purposes should have their performance
tested and documented following methods in ANSI N42.17A prior to their calibration and issuance for field use. If
the user can document that the modifications or substituted components will not affect the instrument performance,
additional ANSI N42.17A testing is not required.
E. Accuracy/Quality Assurance
Quality assurance and quality control activities in a radiation calibration laboratory include specific activities to
establish and maintain the reference radiation field to assure accurate instrument calibration. Requirements for
the possession and maintenance of calibration standards, accuracy of reference radiation fields, and for assessments
of calibration quality are given in this section.
1. Calibration Standards
The calibration laboratory should possess and maintain appropriate radiation and non-radiation standards to
achieve reliable operation. This will involve the use of standards with both implied and demonstrated consistency
to national standards, as well as a laboratory hierarchy of standards and system of constancy checks. The
calibration laboratory should participate in a program to demonstrate consistency for all of its reference radiation
standards through calibrations with NIST or an intercomparison program with other DOE, national or
international laboratories.
The laboratory should have and maintain secondary or tertiary radiation measurement standards (laboratory
standards) to cover the range of calibrations performed. For tertiary laboratories, calibration standards must
themselves be calibrated against a secondary or primary standard. The laboratory standards should be used only
for calibration of working standards. A working standard should be used in lieu of a laboratory standard for
routine calibration operations. For example, if a laboratory sends an ion chamber to the NIST and uses the NIST-
calibrated ion chamber to calibrate the laboratory's calibration source, the NIST-calibrated ion chamber is
considered to be the laboratory standard. The laboratory should then calibrate a second ion chamber using their
calibration source. This second ion chamber is the working standard and should be used for routine calibrations
and the ion chamber calibrated at NIST should be set aside and maintained as the laboratory standard.
The laboratory radiation standards are used to establish the reference radiation fields. Radioactive sources used as
radiation standards should be corrected for radioactive decay. For non-radiation quantities (e.g., temperature,
humidity, pressure, voltage, current, etc.), the facility may use standards based on traceability to NIST.
A secondary laboratory should have a barometer and thermometer capable of ñ1% accuracy (NIST 812 (Part A,
4.2)). For secondary laboratories, these (barometer and thermometer) may be calibrated by comparison with a
tertiary or higher level standard. A calibrated hygrometer capable of monitoring the full range of relative humidity
within which the laboratory operates should also be available.
2. Reference Radiation Field Requirements
The calibration laboratory should establish its reference radiation fields in a manner that provides demonstrated
consistency with national standards. Methods of demonstrating the consistency of reference radiation fields with
national standards may be found in NIST 812 (Part B1, 5.4; Part B2, 5.4; Part B3, 5.5; Part B4, 5.3; Part B5, 5.2).
Stated accuracy for the reference radiation field should include an analysis of all uncertainties, including uncer-
tainties in positioning of standards, uncertainties in environmental corrections, etc.
3. Maintenance of Standards
The laboratory's quality control procedures should be designed to discover undesired changes in equipment
performance, upon which the quality of calibrations depends. The procedures should also be designed to detect
changes in the quality of the services performed. The quality control methods and their frequency of use should be
specified in the laboratory's procedures. The uses of redundant instrumentation, constancy checks, control charts,
detailed procedures, and redundant calibrations are the major quality assurance/quality control activities.
All reference fields and measurement standards should be subjected to a system of constancy checks. This includes
not only the reference radiation standards but also thermometers, timers, voltmeters, barometers, pressure gauges,
and other measuring devices used during the calibration process. For instrument testing, constancy checks should
extend to radio frequency field intensity and other parameters.
Constancy checks are performed by comparing indications between two or more measuring standards. The results
of these measurements should be documented on control charts, and the quality control program should indicate
when such comparisons will require additional investigation. The required investigation or other activity should
also be indicated.
4. Assessments
The activities within the calibration laboratory shall be audited such that, over a three year period, all functional
elements are assessed, including program content and implementation (10 CFR 835.102). All records, calibration
reports, constancy checks, procedures, and other facility documents should be audited at least every two years by an
independent group and documented. The audit should ensure that procedures are current and that actual practices
are consistent with the procedures. The facility should also participate in a periodic proficiency test or an
intercomparison program.
Instrument calibration quality should be audited by supervisory personnel periodically (not less than quarterly) and
documented. Audits should consist of randomly selected instrument recalibrations and observations of
calibrations.
F. Laboratory Documentation
The calibration laboratory should maintain three important sets of documentation: (1) the laboratory protocol; (2)
the laboratory records; and (3) the calibration records. Historical records should be maintained which detail any
changes or revisions in procedures or protocols. The laboratory protocol describes the laboratory operations, i.e.,
what the laboratory is expected to do and how it is expected to do it. This documentation should also include the
detailed calibration procedures for each instrument routinely calibrated. The laboratory records, on the other hand,
is that set of records which documents the actual activities of the laboratory. Finally, the calibration records is that
set of records which documents the maintenance, calibration, and testing of each instrument and source used.
1. Laboratory Protocol
Each DOE laboratory should have a written protocol for calibration of portable survey instruments. Components
that should be included in the protocol are listed in NIST 812 (Part 5.1).
2. Laboratory Records
Guidance for record-keeping can be found in ANSI N13.6, American National Standard Radiation Protection
Practice for Occupational Radiation Exposure Records Systems (ANSI, 1989c), and additional guidance may be
found in Implementation Guide DOE G 441.11-1, Occupational Radiation Protection Record-Keeping and
Reporting (DOE, 1997a).
3. Instrument Calibration Records
A record shall (10 CFR 835.703(d)(1)) be maintained for results of calibration and maintenance performed for
each instrument. This should include:
-- Records of functional tests (operational checks);
-- repair and modification data;
-- both as-found data and data on the final calibration results for the instrument;
-- dates and identity the individual performing the work on the instrument;
-- the uncertainty of the calibration;
-- a generic analysis of uncertainty which should include an analysis based on random checks of calibrated
instruments.
Records related to a particular instrument should be filed with previous records on the same instrument in
accordance with ANSI N13.6.
4. Instrument Location
A system for tracking the location of portable survey instruments and for recalling those instruments for
recalibration shall be established (ANSI N323). The location of portable survey instruments should be known by
the calibration staff or by some identifiable group assigned with that responsibility. Because instruments may
incorporate or be accompanied by an accountable source, instrument tracking may be required as part of the
source-control program.
G. Laboratory, Equipment, and Staff
The location, design, and use of the laboratory for calibrations should ensure that conditions within the laboratory
will not affect calibration quality. In addition, the laboratory shall be designed to keep worker exposures ALARA
in compliance with 10 CFR 835.1001, 10 CFR 835.1003, and DOE Order 420.1, Facility Safety (DOE, 1995). The
laboratory should also have an appropriate selection of calibration equipment and should be operated with a
properly organized and trained staff. Additional guidance may be found in Implementation Guide DOE G 441.2-1,
Occupational ALARA Program (DOE, 1997b), and Chapter 3 of the DOE Radiological Control Standard (DOE,
1997c).
1. Laboratory
The effect of external conditions on the internal environment of the calibration laboratory should be considered in
selecting the facility site. The laboratory should be sited away from, or otherwise isolated from, sources of
mechanical vibration and shock, sources of electrical and electromagnetic interference, and other potential sources
of interference with the proper calibration of instrumentation. If such potential sources exist, the laboratory should
have documentation that demonstrates an absence of adverse effects on calibration accuracy.
The electrical power should be appropriate for the equipment used, suitably stable, and free of switching surges and
significant line noise. When necessary, local auxiliary voltage stabilizers, filters, and uninterruptable power
supplies should be provided.
The laboratory environment should be controlled to ensure that environmental conditions do not affect the
calibration quality. Table 1 in ANSI N42.17A shows the standard conditions that should be established for the
laboratory.
Calibration areas should not be used for storage of instruments, equipment, or sources. Such storage may lead to
variable scatter or abnormal ambiant radiation conditions.
For secondary laboratories, free-space geometry should be achieved for photon and neutron instrument calibration.
The distance to scattering objects from the source and from the detector should be at least twice the distance
between the detector and source. The scattering conditions in the laboratory should be known, and where
scattering contributes significantly to instrument readings, the conditions should be included in stating the value of
the radiation field for all detector positions used for calibration purposes. For routine calibrations at tertiary
laboratories, it may not be necessary to establish free-space calibration conditions. Calibration wells or calibration
boxes may be suitable. For all calibration geometries the effect of scattering and attenuators on calibration
accuracy should be evaluated and documented.
Instrument calibration assemblies shall (ANSI N323(5.2)) be mechanically precise to ensure that positioning
uncertainties of either instruments or radiation sources do not affect the radiation field values by more than ñ2%.
A sufficient range of radiation fields should be available to satisfy instrument calibration requirements.
ALARA processes as described in the RPP should be applied to calibration activities. To meet this condition,
personnel shielding, remote instrument reading and positioning facilities, automatic source handling mechanisms,
and other mechanical or remote operations are recommended. All areas in the laboratory shall be properly posted
in accordance with 10 CFR 835.601.
2. Instrument Calibration Equipment
Instruments should be calibrated with appropriate standards of known hierarchy derived from national standards.
Working standards derived from secondary or tertiary standards should be used for all routine operations.
Calibrations shall be conducted in accordance with ANSI N323(5.1).
A calibration source (or sources, preferably) should emit radiation at a rate sufficient to reach the full scale of any
instrument to be calibrated. If the source is a radionuclide, the half-life should be long, preferably greater than
several years, to minimize corrections and uncertainties. Appendix A lists recommended reference sources for
calibration and standards, or publications where they are described in more detail.
3. Calibration Staff Qualifications
The calibration laboratory manager should have the authority to conduct operations free from any influence that
could adversely affect the quality or impartiality of the services offered. This individual should have a minimum of
a bachelor's degree in physics, engineering, health physics, or radiological physics; a graduate degree in one of
these or a closely related scientific field is highly desirable. This individual should understand the laboratory
protocol, ensure it is followed, and should, at least annually, evaluate staff competence and the need for training.
The individual(s) in charge of day-to-day operation of the laboratory should have at least three years of practical
experience in radiation measurement, including calibration of radiation instrumentation. In smaller operations,
the manager may also be in charge of day-to-day operations.
4. Calibration Staff Training
All staff employed in calibration work shall be trained in radiation safety prior to receiving occupational exposure
(10 CFR 835.901(a)). Additional guidance may be found in Implementation Guide DOE G 441.12-1, Radiation
Safety Training (DOE, 1997d).
Staff should receive Radiological Worker I training. In some facilities Radiological Worker II training or a
combination of Radiological Worker I training with supplemental High Radiation Area training will be required
because of the need to enter high radiation areas (10 CFR 835.901). Key staff members should receive
Radiological Worker II training so that they can participate in possible recovery operations (e.g., a stuck source)
where their knowledge may be critical. Although radiation protection personnel will be responsible for performing
such recovery operations, it may be beneficial for a member of the calibration staff who is fully familiar with the
layout of the laboratory and the types, characteristics, and locations of sources within the laboratory, to assist in
the recovery operations. Refer to DOE STD-1107-97, Knowledge, Skills, and Abilities for Key Radiation
Protection Positions at DOE Facilities (DOE 1997e).
Apart from radiation safety training, the staff should receive training on the theory of radiation detectors,
interaction of radiation with matter, basic statistics, maintenance of records, quality assurance, and other topics
related to the safe and efficient operation of calibration equipment.
V. REFERENCES
(AEC, 1954) Atomic Energy Act of 1954, as amended. Public Law 83-703 (68 Stat. 919), Title 42 U.S.C. sec.
2011.
(ANSI, 1983) American National Standards Institute. 1983. American National Standard Radiation Protection
Instrumentation Test and Calibration. ANSI N323-R1983. New York, New York.
(ANSI, 1989a) American National Standards Institute. 1989. Performance Specifications for Health Physics
Instrumentation - Portable Instrumentation for Use in Normal Environmental Conditions. ANSI N42.17A-1989.
New York, New York.
(ANSI, 1989b) American National Standards Institute. 1989. Performance Specifications for Health Physics
Instrumentation - Portable Instrumentation for Use in Extreme Environmental Conditions. ANSI N42.17C-1989.
New York, New York.
(ANSI, 1989c) American National Standards Institute. 1989. American National Standard Radiation Practice for
Occupational Radiation Exposure Records Systems. ANSI N13.6-R1989. New York, New York.
(DOE, 1993) U.S. Department of Energy. 1993. Environmental Protection, Safety, and Health Protection
Standards. DOE Order 5480.4. Washington, D.C.
(DOE, 1993) U.S. Department of Energy. 1993. Procedural Rules for DOE Nuclear Activities. 10 CFR 820, 58
FR 43680, Federal Register, Vol. 58, No. 157: August 17, 1993. Washington, D.C.
(DOE, 1995) U.S. Department of Energy. 1995. Facility Safety. DOE Order 420.1. Washington, D.C.
(DOE, 1996) U.S. Department of Energy. 1996. Occupational Radiation Protection. 10 CFR 835, 61 FR 67600. Federal Register Vol. 61, No. 247: December 23, 1996. Washington, D.C.
(DOE, 1997a) U.S. Department of Energy. 1997. Occupational Radiation Protection Record-Keeping and
Reporting. DOE G 441.11-1. January 1997, Washington, D.C.
(DOE, 1997b) U.S. Department of Energy. 1997. Occupational ALARA Program. DOE G 441.2-1. January
1997, Washington, D.C.
(DOE, 1997c) U.S. Department of Energy. 1997. Radiological Control Standard. DOE-STD-XXXX-97.
Washington, D.C.
(DOE, 1997d) U.S. Department of Energy. 1997. Radiation Safety Training. DOE G 441.12-1. January 1997,
Washington, D.C.
(DOE, 1997e) U.S. Department of Energy. 1997. Knowledge, Skills, and Abilities for Key Radiation Protection
Positions at DOE Facilities. DOE-STD-1107-97, Washington, D.C.
(NCSL, 1989) National Conference of Standards Laboratories. 1989. Recommended Practice RP-1,
Establishment and Adjustment of Calibration Intervals. Boulder, Colorado.
(NIST, 1991) Eisenhower, E. H., editor. 1991. Criteria for the Operation of Federally-Owned Secondary
Calibration Laboratories (Ionizing Radiation). National Institute of Standards and Technology, Special Publication
812. U.S. Department of Commerce. Washington, D.C.
VI. SUPPORTING DOCUMENTS
Heaton, II, H. T., and G. T. Lalos. 1983. Calibration Handbook: Ionizing Radiation Measuring Instruments.
Naval Surface Weapons Center. White Oak, Maryland.
International Atomic Energy Agency. 1971. Handbook on Calibration of Radiation Protection Monitoring
Instruments. IAEA Technical Report 133. Vienna, Austria.
U.S. National Bureau of Standards. 1981. Requirements for an Effective National Ionizing Radiation
Measurements Program. NBS Special Publication 603. U.S. Department of Commerce. Washington, D.C.
Appendix A
Reference Sources for Calibration
Radiation Type
Reference Source
Reference
DOSE RATE
Gamma
X-ray
X-ray (K fluorescence)
Neutron
Beta
137Cs(a), 60Co(a) and 241Am
M30(a), H50(a), H150(a),
H200(a), H250(a), H300(a), M150, and S60
16, 24, 34, 43, 58, 78 and 100 keV
252Cf(a), 241Am-Be(a),
and 252Cf+D2O moderator
90Sr-90Y(a) and 204Tl(a)
ISO-4037-1979(E)
NBS Spec. Pub. 250-1989
ISO-4037-1979(E)
ISO-8529-1989
ISO-6980-1985
SURFACE
CONTAMINATION
Alpha
Beta
241Am, 230Th(a) and 239Pu(a)
90Sr- 90Y(a), 14C, 147Pm, 36Cl,
204Tl(a), 106Ru-106Rh, U-Nat and U-Dep
3H
ISO-8769-1991
ISO-7503-1-1988a
ISO-7503-2-1988b
_______________________
(a) ANSI N42.17A-1989
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