ML20217R370
| ML20217R370 | |
| Person / Time | |
|---|---|
| Issue date: | 07/25/1997 |
| From: | Cool D NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Bangart R NRC OFFICE OF STATE PROGRAMS (OSP) |
| Shared Package | |
| ML20217Q380 | List: |
| References | |
| NUDOCS 9709050109 | |
| Download: ML20217R370 (6) | |
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July 25, 1997 MEMORANDUM TO:
Richard L. Bangart, Director Office of State Programs FROM:
Donald A. Cool, Director DMslon of Industrial and Medical Nuclear Safety, NMSS
SUBJECT:
EVENT INVOLVING UNAUTHORIZED REPAIR OF HIGH DOSE RATE REMOTE AFTERLOADER AT PIEDMONT HOSPITAL, ATLANTA, GEORGIA On December 18,1990, a hospital physicist at Piedmont Hospital, an Agreement State licensee in Atlanta, Georgia, conducted an unauthorized repair to a GammaMed High Dose Rate (HDR) unit that contained 7.5 curies of Iridium 102. Specifically, the physicist attempted to repair a limit switch which was disconnected. However, during the attempt, the starter motor was enargized causing the source to move out of the device to an unshielded position. The physicist exited the room, obtained a self reading dosimeter, and then reentered the room with a survey meter. He subsequently handled the cold end of the source cable to place the source in the manufacturer supplied emergency storage container, Following the repair, the self-reading dosimeter recorded 14 mrem and the physicist film badge was sent for emergency
- analysis, in a recent discussion with my staff concerning this case, a concern was raised that the State of Georgia may not have adequately followed up on this event for the unauthorized repair of the HDR unit. While the actual safety consequence of the case may have been limited, the potential safety consequence and regulatory significance are high. Therefore, it appears that this issue warrants examination dunng the next Integrated Materials Performance Evaluation Program review of response to incic' ants and allegations.
cc: C. Paperiello CONTACT: Nader L. Mamish,IMNS/NMSS (301)415-6316 w
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PRICRITY ATTENTION REQUIRED NORNIN3 REPORT - RE3 ION II D C.
19, 1996
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Licensee / Facility:
Notificattegu Piedmont Hospital, Atlanta, Ga MR Number 2-96-0123 Piedmont Hospital, Atlanta, Ga Date: 12/19/96 Atlanta, Georgia subiect: HIGH DOSE RATE (HDR) BRACHYTHERAPY AFTERLOADER WITH LIMIT SWITCH FAULT ReRortable Event N"=her 31476 Discussiont Georgia, an A notified the NRC on December 18, 1996, that the licensee'greement State, i
s Physicistihad reported a malfunction of a return limit I
switch in a GammaMed HDR unit containing 7.5 curies of iridium-192.
During an unauthorized attempt to repair the switch, the source was backed out of the device, to an unshielded position.
The physicist p
recovered the source, secured the device, performed surveys, and determined that there was no source leakage.
Exposure to the physicist was estimated to be less than 50 millirem whole body.
The State is continuing to follow the incident and the mechanical cause of the malfunction will bc determined by the device manufacturer and reported to the State.
Region II will follow up with the State regarding any generic-issues related to the event.
-contact 1 R. Woodruff (404)331-5545
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%,#lN Mra W@ i ?!WWM%idgN;N$ N knMM hWphjWin Licensee!: Piedmont Hospital License No. GA 292 2 i
Location pf Event : 1968 Peachtree Road, NW Atlanta, Georgia 30309, Atlanta, GA 30606 Tel #
(404)-605 3319 Descripti6n of Event :Just before 8:00 a.m. the hospital physicist attempted to repair a HDR limit switch th6t was giving a fault signal. When the switch was disconnected the starter motor was cnergize$ and backed the source cable and source out of shielded storage. When the motor was cnergized the physicist stated that he turned to observe the PrimeAlert and it started flashing. He' exited the room, obtained self reading dosimetry, using a radiation survey instrument he reentered the room ' nd handling the ' cold' end of the cable placed the source in the manufacturer supplied a
emergency storage container. The physicist checked the unit for contamination as an indicator of the source having been breached upon exit of the unit. No contamination was found. The supplier has been contacted to repair the unit, load a new source, and retrieve the old source.
These ac) ion are expected to occur on Friday Dec. 20,1996. The source in the emergency storage container is stored in a secure location.
The Physicist estimates his radiation exposure cs less than 50 mrem. The self reading dosimeter recorded 14 mrem while placing the source in the shielded container. Film badge to be sent for emergency analysis. Report received from Hospital 1/8/97.
lsotope : lr-192 Amount of Activity : - 7.5 Ci Date of Event : 12/18/96 8:00 am Date of Report to RCP ' 12/18/96 - 10.00 am Were any other licensees involved, if so identify below : None Licensee License No. -
Describe clean up actions taken by RCP None List radialion measurements taken by Licensee : one meter from storage container - 15 mrem; at maze entrance to room with source unshielded - 15 mrem, at door (door open) to maze with source unshielded 0.04 mrem, and at door (door closed) to maze - background.
List any other actions required of RCP : None List any actions taken to notify the NRC, other Agreement States of Licensees (reference of All Agreement States Letter dated July 22,1986, entitled " Exchange of Information on incidents involving Radioactive Materials" found in NRC Reportable Events - Criteria and Forms noiebook to determine items which require notification) : NRC notified by phone and copy of this surimary.
Case Closed : Yes_X No_
Date Closed : 1/8/97 Record ofilncident in RAM files : Yes X No _
Report file created? Yes)L Date 12/19/93_
Enforcement Action Taken : None
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To B 301 415 35o2 P.03 l
From:
Garry Nixon /FBA <Garry Nixon /FBA@barkemet.com>
To:
henry _copeland < henry _copeland@ mall.dnr. state.ga.u...
Date:
Tuesday, January 28,1997 2:33 pm
Subject:
Response to our phone conversation of Monday, Jan. 27 This is the l ecord of Service at Piedmont Hospital, Atlanta, GA regarding Improper, untrained and l
unauthorizod service performed by the hospital physicist and repair by a GAMMAMED Service Engineer.
Dato completed: 12/20/96 Description of Problem: Received con sole error message "ESRQ defective" during QA.
Hospital Physicist Action Taken:
He attemptod to address what he perceived as the cause of the error message himself by removing the assembly containing the mechanical micro. switches ESRQ and ESRD, Not being a factory trained technician authorized by the both the manufacturer and the NRC to perform maintenance on Gammamed HDR units, he neglected to remove AC and DC power from the HDR unit, which caused the Source wire to be driven backward into the machine (due purely to his actions, not to any design defect of tha machine.) To say that the source was inadvertently exposed due to a design defect in the machina would be like saying that there is a design,defect in a toaster because someone who had not been properly trained in its repair was shocked by not unplugging it prior to attempting servicing it.
GAMMAMED Service Engineer Action Taken:
1: Replaced micro switches ESRQ and ESRD to resolve "ESRO defective" error received during QA.
Date completed: 12/26/96 Description of Problem:
Returned to replace source GAMMAMED Service Engineer Action Taken:
1: Did normal source exchange.
2: Re. surveyed room; all within limits.
- 3. Adjusted park position ancl step position, All OK.
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From:
Henry Copeland l
To:
internet:Garry, Nixon /FBA@barkernet.com l
Datz Thursday, January 30,199710:28 am l
Subject:
Your message of 1/28/97 l
Thank you ior the information that you sent. Tom Hill, our Program Manager, has reviewed it and he requests that you please include in your message a description of the micro switch design featuras, 1.0., how they are designed to work normally, and also the rationale for the design, in other words, include the operation sequence of the switches prior to an actual treatment, and why the source wire j
retracts in the absence of the micro switch, if you have any questions, please call me at (404) 362 2675,or send me an E-mail message. Thanks again for your help.
CC:
Tom Hill kl
,,,,,AuG-01-1997 li nC DRoM EPD RADI AT10tl PFCORAf15 To e 301 413 3302 P. 0".
From:
Garry Nixon /FBA <Garry,_ Nixon /FBA@barkernet.com>
Tc:
henry _,copeland < henry,_copeland@ mail.dnr. state go.u...
Data:
2/10/97 4:09pm
Subject:
Response to your message of 1/30/97 C:mponent Definitions:
ESRD - Me&anical limit switch which indicates the condition DUMMY IN IDLE POSITION ESUD - Op1 1 cal Sensor indicating the condition DUMMY IN IRRADIATION POS.1 ESRQ - Me::hanical limit switch indicating the condition SOURCE IN SHIELDING ESOQ - Op:ical Sensor indicating the start of the source extension A Description of The Micro switch Features and Operation Sequence: When all limit switches are functioning'and the programmed probes are locked into the indexer, the dummy wire is driven out in the guide it be up to the lower stop position ESUD. In case of failure the error reports concerning the limit switches appear.
After a successful probe and dummy test the source can drive out. However, before the source drives out to the first treatment position, the emergency-drive is tested in order to do this, the source wire is driven away from the limit switch ESRO (source retracted) up to the limit switch ESOQ.
Subsequently it is drawn back by the emergency drive of the GAMPW circuit board. This is done to check whet ier the mechanicallimit switch ESRO has changed state after the optical limit switch ESOQhas signaled the position DRIVEN OUT. In case ESRO did not react the error message ESRO DEFECTIV 5 follows and the program is terminated.
The Ration ile for This Design:
This is a closed tube system - the guide tube that the source wire is located in is completely closed.
Normally Wien the source is completely retracted into the depleted Uranium shielding, the proximal cnd of the wire is pressing against the actuating lever of the mechanical Micro switch called ESRO.
The wire CANNOT retract any further because this is a closed tubel The way that this source wire was driven out of this tube was that the switch which is at the end of this closed tube, was removed.
Since the switch assembly was then no longer being actuated by the end of the source wire, the Emergencf Retract sequence was initiated. This happened because the switch assembly was removed from the end of the guide tube without removing power from the machine! All Manufacturer Trcined Se vice Engineers know this will happen, but the user (who is not Manufacturer Trained) attempted to replace this switch, the proper procedure of removing power from the HDR unit was not adhered to, thus resulting in an exposed source.
Garry F. Ni<on l Voice: 1-800-2-BARKER ext.607 l Fax: 1-201-3351225 N;tional Service Manager l E MAIL: GNixon@BARKERNET.com Frcnk Bark 3r Associates, Inc. l WWW: http://ww.BARKERNET.com CC:
Jeff Stickler /FBA <Jeff,_ Stickler /FBA%FBA@notesgw.c...
t l
TOTAL P.o'.