United States Nuclear Regulatory Commission - Protecting People and the Environment

Bulletin 97-01: Potential For Erroneous Calibration, Dose Rate, or Radiation Exposure Measurements With Certain Victoreen Model 530 and 530SI Electrometer/dosemeters

                                                              OMB No. 3150-0012
                                                              NMED No. 970255
                                                              NRCB:  97-01

                                   UNITED STATES
                           NUCLEAR REGULATORY COMMISSION
                 OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS
                              WASHINGTON, D.C. 20555

                                  April 30, 1997


NRC BULLETIN 97-01:  POTENTIAL FOR ERRONEOUS CALIBRATION, DOSE RATE, OR        
                     RADIATION EXPOSURE MEASUREMENTS WITH CERTAIN VICTOREEN    
                     MODEL 530 AND 530SI ELECTROMETER/DOSEMETERS


Addressees

        For Action -      Nonreactor licensees that possess one of the Victoreen
                          Electrometer/Dosemeters specified in this bulletin

        For Information - Other medical institution licensees, irradiator
                          licensees, manufacturing and distribution licensees,
                          and calibration service licensees


Purpose

The U.S. Nuclear Regulatory Commission is issuing this bulletin to:  (1)
notify addressees about the potential for erroneous calibration, dose rate,
and radiation exposure measurements with certain Victoreen Electro-
meter/Dosimeters; (2) request that all action addressees take the actions
specified below; and (3) require that all action addressees provide NRC with a
written response to this bulletin.

Description of Circumstances

On March 26, 1997, Victoreen notified NRC that some of its Model 530 and 530SI
Electrometer/Dosimeter instruments are susceptible to developing cracks in
internal resistor networks (see Attachment 1).  Victoreen submitted a more
detailed written report on April 11, 1997 (see Attachment 2).  In this latter
report, the affected models and corresponding serial numbers were specified as
follows:

        Model 530         Serial numbers 101 though 250; and

        Model 530SI       Serial numbers 101 through 128.



9704300128.                                                              NRCB 97-01
                                                              April 30, 1997
                                                              Page 2 of 4


Affected models may have, or may develop, a cracked resistor network that
could cause erroneous radiation exposure readings either above or below the
actual values.  Furthermore, if a defective instrument is used as a
calibration standard or in determining a calibration standard, any such errors
will be propagated in all subsequent measurements made with the erroneously
calibrated devices or standards.  Various measurements routinely made by NRC
licensees could be affected, such as, medical therapy device exposure rates,
radiation surveys, and personal dosimetry. 

Discussion

The Victoreen Models 530 and 530SI Electrometer/Dosemeters are high-precision
electrometers designed to accept various commercially available ionization
chambers.  These instruments can be used to either measure electrical charge
or current, or, through the use of customer-supplied calibration factors,
display these values directly as total exposure (Roentgens or Grays) or
exposure rates (Roentgens/minute or Grays/minute).  The defective resistor
networks comprise part of the calibration factor selection circuitry.  If one
of these resistor networks cracks, the instrument may actually use a
calibration factor other than the one selected by the user, producing
erroneous values for exposure and exposure rate measurements.

When operated as an electrometer, performing traditional charge or current
measurements, the manufacturer indicates that such measurements do not use the
problem resistor networks and the charge and current measurements obtained
will not be affected by any failures in these resistor networks.  Similarly,
the manufacturer indicates that if a user does not have any calibration
factors stored in the instrument, a cracked resistor network cannot affect the
radiation exposure measurement results because there are no calibration
factors to select.

The potential for a substantial safety hazard exists because measurements made
with a defective instrument may result in radiation exposure readings that can
be either above or below the actual values by an unknown amount.  Furthermore,
if an instrument with this fault is used as a calibration standard, all
subsequent devices calibrated with reference to the faulty instrument may be
in error.  If used to calibrate medical therapy exposure rates, patients may
be administered radiation over or under the prescribed dose, resulting in
potentially significant misadministrations.  If used to calibrate survey
instruments or personal dosimeters, users may be exposed to radiation levels
exceeding allowable limits.

Requested Actions

Licensees possessing an instrument with a model number and serial number
within the range specified above should immediately implement the following
actions before any further use of the instrument in performing exposure or
exposure rate measurements:

1.      Perform the "Customer Corrective Action" recommended by Victoreen to
        determine if your instrument contains the type of resistor network shown
        in Figure 2 of Victoreen's report (Attachment 2).
.                                                              NRCB 97-01
                                                              April 30, 1997
                                                              Page 3 of 4

2.      If the resistor networks are of the type shown in Figure 2 --

        a.  immediately cease all exposure or exposure rate measurements until
            the resistor networks are replaced and functionally tested; and

        b.  investigate the operational history of the instrument and identify
            the activities that may have been affected by erroneous exposure or
            exposure rate measurements including calibration services provided
            to other facilities.

Required Responses

1.      Within 15 days of the date of this bulletin, each action addressee is
        required to submit a response indicating whether the addressee will
        implement the actions requested above.  If the addressee intends to
        implement the actions, provide a schedule for completing the actions. 
        If an addressee chooses not to take the requested actions, provide a
        description of any proposed alternative course of action, the schedule
        for completing the alternate actions (if applicable), and the safety
        basis for determining the acceptability of the planned alternative
        actions.

2.      Within 30 days of completing the requested actions, each action
        addressee is required to submit a report confirming completion of the
        actions and documenting the results of the investigation specified in
        Action 2.b.

Address the required written responses to the U.S. Nuclear Regulatory
Commission, ATTN: Document Control Desk, Washington, D.C. 20555, under oath or
affirmation, under the provisions of Section 182a, of the Atomic Energy Act of
1954, as amended.  In addition, submit a copy to the appropriate NRC Regional
Administrator.

Licensees should also be aware that electrometers are regulated as medical
devices by the U.S. Food and Drug Administration (FDA) if they are used for
the calibration of radiation therapy systems that administer patient
treatments.  Under FDA regulations, Medical Device User Facilities are now
subject to mandatory FDA adverse event reporting requirements for medical
devices.  Information concerning FDA's mandatory reporting requirements can be
obtained by contacting the Center for Devices and Radiological Health, Office
of Surveillance and Biometrics, Division of Surveillance Systems, at 301-594-
2735.  Since the FDA mandatory reporting requirements may not be applicable to
all medical device events, FDA also depends on information voluntarily
provided by device users because they are often the first to recognize medical
device-related hazards.  Any concerns that licensees may have regarding safety
or quality problems associated with medical devices can be voluntarily
reported to the FDA by calling MedWatch at 1-800-FDA-1088.  Voluntary reports
can be submitted anonymously.

Paperwork Reduction Act Statement

The information collections contained in this request are covered by Office of
Management and Budget clearance number 3150-0012, which expires June 30, 1997. 
The public reporting burden for collecting this information is estimated to
average 40 person-hours per response.  This estimate includes the time for
reviewing instructions, searching existing data sources, .                                                              NRCB 97-01
                                                              April 30, 1997
                                                              Page 4 of 4


gathering and maintaining the data, and completing and reviewing the
collection of information.  Send comments about this burden estimate or any
other aspect of this collection of information, including suggestions for
reducing this burden, to the Information and Records Management Branch,
Division of Information Support Services, Office of Information Resources
Management, U.S. Nuclear Regulatory Commission, Washington, D.C.  20555, and
to the Office of Information and Regulatory Affairs, (3150-0012) NEOB-3019,
Office of Management and Budget, Washington, DC 20503.

Information Addressees

NRC is issuing this bulletin to information addressees to alert them to the
potential for erroneous radiation exposure measurements with certain Victoreen
Electrometer/Dosemeters.  It is expected that recipients will review this
information for applicability to their  facilities and consider actions as
appropriate, to avoid similar problems.  However, the requested actions and
required responses are applicable to action addressees only; therefore, no
specific action nor written response is required from information addressees.

If you have any questions about this matter, please contact one of the
technical contacts listed below or the appropriate NRC regional office.


                                            signed by F. C. Combs for

                                      Donald A. Cool, Director
                                      Division of Industrial and 
                                         Medical Nuclear Safety
                                      Office of Nuclear Material Safety 
                                         and Safeguards

Technical contacts:  Robert L. Ayres, NMSS        
                       (301) 415-5746       
                       E-mail:  rxa1@nrc.gov

                       Kevin M. Ramsey, NMSS
                       (301) 415-7887
                       E-mail:  kmr@nrc.gov

Attachments:
1.  Initial Part 21 Report
2.  Followup Part 21 Report.                                                              Attachment 1
                                                              NRCB 97-01
                                                              April 30, 1997
                                                              Page 1 of 2
                                  Victoreen, Inc.
------------------------------------------------------------------------------
VICTOREEN@
Document Control Desk
US Nuclear Regulatory Commission
Washington, DC 20555

Subject:    Notification of a noncompliance, Model 530 Resistor Network

Reference:  10 CFR Section 21.21
            Notification to the NRC by fax (301) 816-5151
            NRC Operations Center

Date of Notification:  March 26, 1997

Individual Notifying Commission:
Linda S Nash
Corporate Director, Regulatory Affairs

Bill Zimmerman
R&D Engineer

Name and address of company notifying the Commission:
Victoreen, Inc.
6000 Cochran Road,
Cleveland, Ohio 44139-3395
(216) 248-9300

Facility Containing the defect:
Victoreen, Inc.
6000 Cochran Road,
Solon, Ohio 44139

Date on which the condition was identified:  April 15, 1996

Nature of the condition:
Resistor network can crack, causing portions of it or all of it to become
non-functional.

Why we think "this component has caused a substantial safety hazard"
This device has not caused a substantial safety hazard 

                                      6000 Cochran Road,
                                      Cleveland, Ohio 44139-3395
                                      (216) 248-9300
                                      FAX (216) 248-9301
                                      DATA (216) 248-9043
9704010595 970326
PDR PT21 EMVVICTN
97             PDR.                                                              Attachment 1
                                                              NRCB 97-01
                                                              April 30, 1997
                                                              Page 2 of 2

Continuation of notification of Model 530

Why we think "this component could cause a substantial safety hazard":
Measurements made with a defective instrument may result in radiation exposure
readings which are above or below the actual radiation exposure. In the event
that the measured readings are below the actual exposure, the actual exposure
will be more than the measured exposure. In the event that the readings are
above the actual exposure, the actual exposure will be less than the measured
exposure.  If a faulty instrument is used as a primary calibration standard,
all devices calibrated with reference to the faulty device may be in error. 
If used to calibrate survey meters or personal dosimeters, the users of these
devices may be exposed to radiation levels exceeding allowable limits for
radiation workers and others.

Customers/Utilities Affected:
To be determined































                                                                          2.                                                              Attachment 2
                                                              NRCB 97-01
                                                              April 30, 1997
                                                              Page 1 of 4
                                  Victoreen, Inc.
------------------------------------------------------------------------------
VICTOREEN@                        April 11, 1997
US Nuclear Regulatory Commission
Document Control Center
Washington, DC 20555

Reference:  1.  10 CFR 21 Report of Noncompliance dated March 26, 1997
                Model 530 Electrometer
                2.  NRC Fax (301) 816-5151
                3.  Customer list (see attached)

Subject:    Corrective Action and Closeout, 10 CFR Part 21 Report of Noncompliance 
            Model 530 Electrometer

To Whom It May Concern:
Further to our notification dated March 26, 1997, this letter has been prepared to
provide formal notification of the corrective action performed and to close out
the subject 10 CFR Part 21 Report of Noncompliance

General Description:
The Victoreen Model 530 Electrometer/Dosemeter is a high precision, dual polarity
electrometer designed to accept Victoreen and many commercially available
ionization chambers. As an electrometer, it displays charge in nC and current in
pA. As a dosemeter it displays exposure in Roentgens (S.I. version - Gy) and
Exposure Rate in Rmin (Gy/min). Ion chamber calibration factors can be stored in
the model 530 via a computer hookup, but are not required for operation in the
charge or current modes.

This notification identifies the potential for a component failure in some of the
Victoreen Model 530 Electrometer/Dosemeter's (serial numbers 101-250 only)
which under very specific circumstances may cause the Model 530 to calculate
radiation exposures or rates incorrectly. The component that may fail is a
resistor network in the Model 530's calibration select switch circuit. In rare
cases these resistors networks have been observed to crack which causes them to
open and become nonfunctional. If this occurs, the calibration select switch
settings may be read incorrectly by the 530 and one of two things can happen.

1. An -E4- error message is displayed in the Rate and Exposure modes. When this
error message is displayed, no measurements may be made.

2. If multiple ion chamber calibration factors have been stored in the 530, an ion
chamber calibration factor other than the factor indicated by the calibration
select switch may be selected. If this occurs, measurements made in the rate and
exposure modes may be in error. In most circumstances, the user would immediately
identify the problem. If the unit being calibrated experienced a failure of the
same magnitude as the calibration factor error, a substantial safety hazard could
occur. The probability of this occurrence is extremely remote. Although the defect
was originally discovered in April of 1996, the possibility of a substantial
safety hazard was not presented until February 11, 1997. Measurements made in the
charge or current modes are not affected.
                                            6000 Cochran Road,
9704240045 970411                           Cleveland, Ohio 44139-3395
PDR PT21 EMVVICTN                           (216) 248-9300
97            PDR                           FAX (216) 248-9301
                                            DATA (216) 248-9043.                                                              Attachment 2
                                                              NRCB 97-01
                                                              April 30, 1997
                                                              Page 2 of 4
April 9, 1997 - Page 2 of 4

If the user has not stored any calibration factors in the 530, a cracked resistor
network has no effect because the 530 cannot be used in the rate or exposure mode
unless calibration factors have been stored in the 530.

This notification applies to Model 530's with serial numbers between 101 and 250,
and all Model 530SI's with serial numbers between 101 and 128.

.                                                              Attachment 2
                                                              NRCB 97-01
                                                              April 30, 1997
April 9, 1997 - Page 3 of 4                                   Page 3 of 4

Victoreen Corrective Action:
All Victoreen corrective action has been completed.

To correct this problem, the original epoxy coated thick film resistor networks
(Victoreen 185-3994-1) have been replaced with more durable, molded thick film
resistor networks (Victoreen 351041) in all 530's. To implement this change,
Victoreen has taken the following action:

1. Replaced all 185-3994-1 resistor networks with 351041 resistor networks in all
Model 530's that were returned for repair or calibration since April 16, 1996.
(via internal memo)

2. Replaced all 185-3994-1 resistor networks with 351041 resistor networks in all
Model 530's and Model 530 main printed circuit boards that were in stock or in
process since May 15, 1996. (Ref. DCR 4CR25-96).

3. Changed resistor networks on the Bill of Material for the Model 530-100-10 main
printed circuit board from 185-3994-1 to 351041. (Ref. DCR 4CR25-96) since May 15,
1996.

Customer Corrective Action:

Perform the following visual inspection or call Victoreen Customer Service for
assistance.

1. Verify that the Model 530 is turned off and is disconnected from it's AC        
   adaptor.

2. Remove the four Phillips head screws from the front bezel.

3. Lift the front of the top cover to clear the front panel and remove the panel   
   by pulling it forward.

4. Locate resistor networks RN1 and RN4 on the Model 530 printed circuit board per 
   drawing below. (See file BL97001.WP1 for figures).                                                              Attachment 2
                                                              NRCB 97-01
                                                              April 30, 1997
                                                              Page 4 of 4

April 9, 1997 - Page 4 of 4

5. Compare the resistor networks to those pictured below. If they are of the type
shown in Figure 1, (0.35" tall with square corners) no further action is required. 
If they are of the type shown in Figure 2, (0.2" tall with rounded corners)
reassemble the Model 530 and contact Victoreen Customer Service for assistance.
(See file BL97001.WP1 for figures)

Root Cause Analysis:

From our review it has been determined that the cracking of this resistor network
may be the result of manufacturing defects or by mechanical stress, vibration or
thermal shock. In our normal processing of these parts they are not subjected to
any excess stress, vibration or thermal shock. The functionality of these parts
has been tested and is tested on every Model 530 main printed circuit board as
part of Victoreen's standard test procedure for this product (Ref. TP530-100-10).

We thank you for your cooperation in this matter. Please advise if you have any
questions or comments of the information provided here-in.

Best Regards                                            

(signed Linda S Nash)                       (signed Bill Zimmerman)

Linda S Nash                                Bill Zimmerman
Corporate Director                          Senior R&D Engineer
Regulatory Affairs & Q.A.

 

 

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