Event Notification Report for April 03, 2002

AGREEMENT STATE REPORT REGARDING YTTRIUM-90 CONTAMINATION OF THE HARRISON MEMORIAL HOSPITAL NUCLEAR MEDICINE HOT LAB DUE TO RECEIPT OF AN IMPROPERLY SEALED OR PACKAGED INNER CONTAINER SENT FROM TACOMA CENTRAL PHARMACY

The following text is a portion of an e-mail received from the Washington State Department of Health, Division of Radiation Protection:

"Licensee: Harrison Memorial Hospital
City & State: Bremerton, Washington
License #: WN-M0168-1
Type license: Nuclear Medicine"

"Date of event: April 3, 2002
Event Location: Nuclear Medicine Hot Lab"

"Abstract: Harrison Memorial (licensee) reported that they had received a nuclear medicine shipment, at about noon on April 3. It went directly into the hot lab after going through preliminary receipt procedures at the licensee's receiving department. The shipper was Tacoma Central Pharmacy, License Number WN-NP005-1. The licensee reported that the shipment had checked in normal including negative dose-rate and wipe receipt surveys. The shipper indicated the activity and isotope to be 24.8 millicuries of yttrium-90. The dose was unpackaged and placed into the dose calibrator for activity verification. At that time, it measured 18.5 millicuries."

"The CNMT realized there was a problem and began to look for the remainder of the dose. Extensive wipe and direct surveys of the hot lab and other areas were performed. The majority of the dose had spilled and remained inside the transportation box (ammo can). Contamination was also found in the hot lab. Prior to being cleaned, the CNMT found between 1700 to 3500 counts per minute on the hot lab counter top and 1700 cpm at the 'L' shield block. The CNMT had used gloves and wore usual hot lab clothing so was not personally contaminated. The CNMT decontaminated the affected areas. A large trash bag of waste was collected. The CNMT was the only person involved in the incident. All activity was contained within the nuclear medicine hot lab. The pharmacy will be responsible for disposal of the waste."

"The CNMT discovered and cleaned up prior to notifying the department. A report with surveys from the licensee is forthcoming. The apparent cause of the incident was an improperly sealed or improperly packaged inner container (syringe) sent from the pharmacy. Both the licensee (Harrison Memorial) and Tacoma Central Pharmacy are due for routine inspections. The incident will be investigated during each of those inspections. The investigation will remain open until on site inspections are complete."

(Call the NRC operations officer for state contact information.)

FITNESS FOR DUTY REPORT INVOLVING CONTRACT SUPERVISOR

A non-licensed contractor supervisor tested positive for alcohol during a for-cause fitness for duty test. The individual's site unescorted access has been removed. Contact the Headquarters Operations Officer for additional information.

The NRC Resident Inspector was notified of the event by the licensee.

The licensee also notified NRC Region 4 (Dennis Schaefer) of the event.

24-HOUR NRC BULLETIN 91-01 (CRITICALITY CONTROLS) ISSUE AT FRAMATONE ANP RICHLAND

"Background: FRA-ANP routinely uses 45-gallon drums that contain a neutron absorbing spider assembly for processing and storing unmoderated urania powder. The spider assembly is inserted into the drum and bolted to the drum bottom. This spider assembly is designed such that it will prevent criticality in a single drum even if the drum is accidentally filled with an optimum mixture of UO2 and water and is also fully reflected by water. Accidental disassembly is prevented by the spider assembly design. However, when a drum reaches the end of useful service, or if the drum will no longer be used for dirty or Gd contaminated powder, the neutron absorbing spider assembly is removed and reused with a new 45-gallon drum. The old drum sans insert is then destroyed.

"Event Description: On swing shift April 2, 2002 process operators removed the neutron absorbing spider assemblies from three 45-gallon drums per standard operating procedure (SOP). Operators moved these three drums to the old waste area.

"Around midnight, a process operator retrieved one of the 45-gallon drums in the old waste area instead of going to the powder storage area to retrieve a 45-gallon drum. He transferred it to a nearby utility hood and used it to prepare a blend of unmoderated dirty urania powder for subsequent dissolution. The process operator failed to perform a required visual inspection of the interior of the 45-gallon drum prior to transferring 250 kg of urania powder enriched to 2.7 wt.% U-235 into it. The same process operator secured the lid and transferred it per SOP to another process enclosure where the drum lid is removed and a drum tumbling lid is installed. When the process operator removed the drum lid at about 0230, he noticed the drum did not have a neutron absorbing spider assembly and contacted supervision. Supervision immediately contacted Criticality Safety.

"Safety Significance of Event: The safety significance of this event is low. The urania powder placed in this drum was known in advance to contain less than 1 wt.% moisture equivalent hydrogen. Two process operators had previously verified the material had acceptable laboratory analysis results and that the correct material had been selected for the blend.

"A sphere of 250 kg UO2 powder enriched to 5 wt.% U-235, with a bulk density of 4 g/cc, and containing 10 wt.% water that is fully reflected by water has a keff of 0.95. Therefore, the material in the drum would have to have more than 10 times the limit before criticality could occur in the drum.

"Potential Criticality Pathways Involved (Brief Scenario(s) Of How Criticality Could Occur): Criticality could only occur if moderation control on the material placed in the drum is lost. This could hypothetically occur if powder containing over 10 times the allowed limit were placed into the drum or if a similar amount liquid water entered a drum from an external source.

"Controlled Parameters (Mass, Moderation, Geometry, Concentration, Etc.): The process parameter controlled in this portion of the process is moderation. An additional design control is the neutron absorbing insert. When installed, this insert will keep the drum sub-critical even if moderation control is completely lost in a single drum.

"Estimated Amount, Enrichment, Form of Licensed Material ( Include Process Limit and % Worst Case Critical Mass): The amount of material involved is 250 kg of urania powder enriched to 2.7 wt.% U-235. The material contained <0.2 wt.% moisture. The process limit is 1.0 wt.% moisture. More than 10 wt.% water and a full water reflector is required for keff to exceed 0.95 at 5.0 wt.% U-235.

"The minimum critical mass for optimally moderated urania powder enriched to 2.75 wt.% U-235 with full water reflection is about 124 kg.

"Nuclear Criticality Safety Control(s) or Control System(s) and Description of the Failures or Deficiencies:
The moderator control system requires that any material placed into a 45-gallon drum have at least on assurance that the material contains less than 1.0 wt.% moisture. The moderation control system includes two operators verifying that acceptable lab analysis results have been obtained and that the correct material has been selected for being dumping into a 45-gallon drum. These operators are also aided by a computer controlled inventory system that also checks for acceptable moisture results on each item being placed on a blend make up list.

"In addition to moderation control, the neutron adsorbing spider assemblies will keep the drum subcritical even if it is filled with optimally moderated UO2. This control failed because a drum without the required insert was inadvertently used in the process. This occurred because the process operator failed to perform a required visual inspection prior to filling the drum. Also, the operating procedure for disassembling 45-gallon drums with neutron absorbing spider assemblies did not require an out of service sign to be posted on the drum.

"Corrective Actions To Restore Safety Systems and When Each Was Implemented: Manager of Criticality Safety convened an Incident Investigation Board at 0330.

"The material involved was transferred to a drum containing a neutron absorbing spider assembly and handled per standard operating procedures. The transfer was completed by 0615.

"All drums that do not contain neutron absorbing spider assemblies were tagged with out-of-service signs and then removed from the area and smashed.

"Drum disassembly, and blend make-up operations have been placed on hold pending completion of procedure revisions and training.

"Additional corrective actions are being evaluated."

Framatome notified Region 4 (B. SPITZBERG).

24-HOUR NRC BULLETIN 91-01 (CRITICALITY CONTROLS) ISSUE AT PORTSMOUTH GASEOUS DIFFUSION PLANT

"At 1159 hours today after Nuclear Materials Engineering completed a review of their databases for batched items stored in 55 gal. drums, it was discovered that 26 drums with questionable Segmented Gamma Scanner (SGS) values were located in the XT-847. The concern about the SGS not correctly counting the U-235 mass was identified earlier but at that time no drums were identified in the United States Enrichment Corporation (USEC) leased spaces. The mass counting error identified between the SCS and the Low Density Waste Assay Monitor (LDWAM) was at times off by a factor of 10 or more. Because of the questionable SGS measurements it could not be assured the 350 gram U-235 limit per batched drum was maintained. The governing NSCA X-0847_ 001. A04 Operation of the XT-847 Facility in it's NCSE accounted for an error of a factor of two in mass calculations, as a bounding condition. Thus with the loss of the bounding calculations and the potential error in mass calculations, this resulted in the loss of both legs of the double contingency basis (mass & the factor of two bounding error) for NCSA X-847_001.A04. At the present time Waste Material handlers in the XT-847 are moving all 26 drums from their storage area to another storage location within the building to allow for remeasurement of the drums. The guidance for moving and relocating these drums for remeasurement is covered by existing procedures and NCSAs.

"SAFETY SIGNIFICANCE OF EVENTS: The safety significance of this event is low because the actual uranium mass content of the drums in question would not be expected to contain more than a safe amount of uranium bearing material. Other similar drums of trapping material batched during the same period using LDWAM measurements contain considerably less than a safe mass of U-235. The uranium mass limits assume optimum moderation and 100% enrichment. The drums in question are known to contain less than 10% enrichment (based upon process knowledge or sampling) and the material stored in the XT-847 is dry trapping material (alumina, etc). Even with the maximum potential error in the SGS measurements, the total mass in any drum (or group) would be less than the safe mass of uranium at an H/U of 4 (wet air moderation of approximately 7.9 kg of U-235 (100% enrichment)

"POTENTIAL CRITICALITY PATHWAYS INVOLVED (BRIEF SCENARIO[S] OF HOW CRITICALITY COULD OCCUR):
For a criticality to occur, the following events would be required: One or more drums must contain greater than a minimum critical mass of uranium (at this time, the measurement results are in question, but greater than a safe mass has not actually been measured in any drum), the contents of the drums would need to be moderated by water or oil (the material is dry trapping material), and some amount of reflection would be required (for the drums, or groups of drums, currently spaced 2 feet edge-to-edge apart).

"CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY. CONCENTRATION, ETC.): The drums were filled by batching small diameter containers of trapping material based upon NDA or sample measurements of the uranium mass present. The batching limits are 43.5% of the minimum critical mass assuming optimum moderation, concentration, geometry, reflection, etc. In the applicable NCSE, credit is taken for a double batch scenario bounding potential uranium mass upsets; however, the potential error in the SGS measurements may be greater than a factor of two. Spacing is controlled for drums, or groups of drums, unless categorized as containing less than 15 grams U-235.

"ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED MATERIAL (INCLUDE PROCESS LIMIT AND % WORST CASE OF CRITICAL MASS): The contents of the drums are dry trapping material from the cascade buildings, and are known to be enriched to 10% or less. At the time they were filled, the total mass was calculated to be less than 350 grams U-235. However, the SGS used to measure source containers has been questioned. The variability of the SGS results indicate that the total uranium mass in containers batched into a drum could be non-conservative by a factor of 10 or more.

"NUCLEAR CRITICALITY SAFETY CONTROL(S) OR CONTROL SYSTEM(S) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES: Recent NDA measurements performed on the Low Density Waste Assay Monitor (LDWAM) have identified discrepancies in the gram quantity of U-235 when compared to the Segmented Gamma Scanner (SGS) measured values (see PR-PTS-02-01398). The SGS values are biased low which could have resulted in underestimatlng the total batch quantity for previously batched drums. Until confirmatory measurements of the drums are obtained, the potential mass content represents a loss of both legs of double contingency as described in the applicable NCSE.

"CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEM AND WHEN EACH WAS IMPLEMENTED: These drums are not safety systems but corrective actions to regain compliance was started at 1530 hours 4/2/02."

The NRC Resident Inspector was notified by the certificate holder.

****UPDATE 4/19/02 at 1533, J. McCleery to R. Laura****

"Update 1: There is no safety significance for this event because all 21 drums have now been confirmed to contain less than a safe mass for the enrichment of material. While one drum was found to exceed the 350 grams U-235 control limit. The actual U-235 mass is less than a safe mass and the process conditions credited for double contingency were maintained. All potential drum groups that could have exceeded 350 gram U-235 were examined, the maximum mass for a drum group would have been approximately 620 grams U-235, at a maximum of 5% enrichment. Therefore, all drum groups would have been below safe mass at process conditions. Criticality was determined noncredible given the new measurements for these drums."

Notified R3DO (J. Madera) and NMSS (F. Brown) of this update.

5 LOST AIR NOZZLE SOURCES

Licensee reports that 5 static eliminator Po-210 sources are missing. All of the sources are 10 micro-curie, with the following serial numbers and dates: #119686 19 Apr 00, #104160 28 Jul 98, #108071 18 Jan 99, #108072 Jan 18 99, and #111277 10 May 99. The Licensee is still looking for the missing sources and has contacted the vendor which has indicated that the sources were never shipped back to the vendor.

OCCUPATIONAL RADIATION EXPOSURE EXCEEDED ANNUAL LIMIT

On April 3, 2002, it was identified that a radiographer had received a total occupational exposure of 5.227 Rem Total Effective Dose Equivalent for the monitoring period of January 1, 2001 through December 31, 2001.

While compiling Occupational Exposure Reports it was determined that the dose received by a radiographer was in excess of the limits allowed by RH 4.6.1.1.1. The Corporate Radiation Safety Department then notified the Denver Lab Manager of the findings. Exposure records have been reviewed to verify the accuracy of the reported exposure. It has been determined that the reported total is accurate as stated.

The radiographer received an exposure of 5.227 Rem Deep Dose Equivalent, and 5.157 Rem Shallow Dose Equivalent for the period of January 1, 2001 through December 31, 2001.

Throughout the monitoring period the radiographer worked at various jobsites. The isotope utilized to perform the radiography was Iridium 192. Varying curie strengths from 10 curies to 100 curies were used throughout the year.

The root cause of the excessive exposure was due to a lack of attention paid to the cumulative exposure total by the Radiation Safety personnel and by the Radiographer. On August 1, 2001 CONAM Inspection switched to a new dosimetry processor. The result was two dosimetry reports, neither having a cumulative total for the year. The radiographer failed to notify his Radiation Safety Officer of the amount of his total exposure and his proximity to the annual limit. Additionally, the Radiation Safety Officer and the Corporate Radiation Safety Department failed to identify the radiographers proximity to the annual limit and remove him from radiographic activities.

The following corrective actions and program enhancements have been made. The Corporate Radiation Safety Department has added a staff member to assist with the oversight of the radiation safety program All monthly exposures in excess of 420 mR now require an ALARA review. All monthly dosimetry reports are reviewed by the lab and by the corporate radiation safety departments to prevent this type of incident. CONAM Inspection intends to utilize our current dosimetry company for the remainder of the monitoring period eliminating the dual reports. The entire radiography staff has been informed of this incident. They have also been instructed of their responsibility to prevent this type of incident. The Radiation Safety Officer has been retrained on his responsibility to ensure that all employees are maintaining their exposure ALARA. When the results from the June monitoring period become available, any employee in excess of 2.5 Rem TEDE will be removed from radiographic activities. Additionally, an employee receiving in excess of 4 Rem will be removed from radiographic activities for the remainder of the monitoring year. The corrective actions are in place as of the date of this letter.