Event Notification Report for November 08, 2000

MOISTURE DENSITY GAUGE MISSING FROM QORE, INC., IN HUNTSVILLE, ALABAMA.

The following text is a portion of a facsimile received from the Alabama Office of Radiation Control:

"FROM: David Turberville, Radiation Physicist II"

"SUBJECT: Alabama Incident File #00-30 - Lost Moisture Density Gauge."

"On the morning of November 8, 2000, Shane Kirby, Radiation Safety Officer for Qore, Inc., of Huntsville, Alabama, notified the Alabama Office of Radiation Control stating that it appears that they have lost a CPN model MC-1 moisture density gauge, serial number M1310598? or M13105089? containing 10 millicuries of Cs-137 and 50 millicuries of Am-241/Be. Qore, Inc. is authorized to possess and use the device under Alabama Radioactive Material License No. 1022. The missing device is one of sixteen devices on the licensee's inventory."

"Mr. Kirby stated that his records indicate that the device was last used in May of 1999 and was last leak tested on May 16, 1999. Mr. Kirby explained the reason the gauge had not been leak tested or inventoried since May of 1999 was because the file for this device was lost since that time and it did not come to his attention until the file was recently found. Mr. Kirby has no records of transfer since August of 1998."

"The Agency last inspected this licensee on January 26, 2000 [...]."

"The licensee continues to search the facilities, notify other branches and licensees, and review records of accountability in an effort to locate the device."

(Call the NRC operations officer for contact information.)

24-HOUR NRC BULLETIN 91-01 REPORT

Event Description:

On 11/08/00 at about 8:35 a.m., while conducting an accountability audit of waste material transfers, a Siemens Power Corporation (SPC) process operator identified that a single 4-gallon container of uranium-containing waste material with a net weight of 10.73 kg had been transferred to a 30-gallon drum without first being sampled.

Further investigation revealed that the 30-gallon drum contained 40 grams 235U exclusive of the material from the unanalyzed 4-gallon bucket, A high 235U value under normal conditions for a 4-gallon container of this waste weighing 10.73 kg would be 54 grams 235U (waste containing 10% U and assuming 5% 235U enrichment). Based on the highest U content observed in waste from this process (25 %U), the worst case 235U content in this 10.73 kg of waste material would be less than 135 grams.

Safety Significance Of Event:

The safety significance of this event is low. Assuming the material from the unanalyzed single 4-gallon container contained uranium at historic maximum levels from this process, the mass of 235U present in the 30-gallon waste drum would be less than 175 g (40g + 135g), which is less than 10% of a minimum critical mass. A safe mass of 235U (45% of minimum critical) is 792 grams, assuming 5 wt.% enriched material. If one assumes that all of the waste material in the unanalyzed 4-gallon container was UO2 (an unrealistic assumption), the mass of 235U present in the 30 gallon waste drum would still be less than 513 g assuming 5 wt.% enriched material. The material actually present is < 3.5 wt.% enriched.

This waste drum had been stored in a two tier array. However, this type of waste drum is allowed to be stored in a 3 tier array. If this drum, as postulated above to contain 175g 235U, and two additional drums each at SPC's 100 g 235U waste disposal limit were present in a three tier stack, the total mass in the stack would have been approximately 375 g 235U. This is less than 22% of a minimum critical mass.

Potential Criticality Pathways Involved:

For criticality to occur in a single waste drum, a minimum of about 1760 g 235U is required. Current SOPs require that two independent individuals verify that waste container U contents have been determined by three independent means before the waste container contents are tabulated on a load list (as acceptable for incorporation into a single drum) and allowed to be transferred to a waste packaging area. Two independent individuals are then required to verify the selected buckets are on the load list before the individual bucket contents can be placed into a 30-gallon waste drum.

At least 1 3 unanalyzed 4-gallon containers of this type of waste material (at historic high U levels from this process) would have to be placed into a drum before criticality is possible.

Multiple additional failures would be required to reach conditions that approach a critical mass in a single drum or in an allowed 3 tier array of drums.

Controlled Parameters:

For waste drums the controlled criticality parameter mass/allowed surface density

Estimated Amount, Enrichment, and Form Of Licensed Material:

The licensed material is uranium bearing solid waste. The total 235U present in the waste drum in question was calculated at worst case historic process waste conditions to be <125 grams, with an actual enrichment of < 3.5 wt.% 235U. This is < 10% of the minimum critical mass of material enriched to 5 wt.% 235U.

Nuclear Criticality Safety Control(s) Or Control Systems and a Description of the Failures Or Deficiencies:

Nuclear criticality safety controls imposed on this waste generation, packaging, and storage process include:

analysis of uranium content in the initial waste buckets by three independent means; second party verification of drum load lists for compliance with waste drum limits;
second party verification that buckets actually received at the drum loading area match those called for by the drum load list.

The control system failed when an operator selected a 4-gallon waste bucket not on the approved load list and the error was not caught by the waste handler tasked to verify that buckets received in the waste handling area matched those on the approved drum load list.

A number of factors may have contributed to the failure, including but not limited to:

1 Human factors issues related to reading very similar alpha-numeric characters (in this case AA4072 vs. AC4072);

2 The practice of placing waste buckets inside plastic bags for the sake of contamination control, prior to their being stored in an unlit cargo container. This necessitates transcribing the container ID number to a piece of tape on the outside of the plastic bag, allowing for the possibility of transcription errors.

3 The practice of storing unanalyzed waste buckets destined for process recycle with buckets destined for placement into waste drums.

A formal SPC Incident investigation Board (IIB) is investigating the incident.

Corrective Actions To Restore Safety Systems and When Each Was Implemented:

The process operators finding the infraction promptly notified Criticality Safety.

Criticality Safety assembled a multi-disciplinary team to review the infraction and determined the safety significance of the incident to be low but that it met the NRC Bulletin 91-01 Criteria as a 24 hour reportable condition.

This team also recommended the following immediate actions:

1 Stop loading waste drums with this type of material. (completed
2 Account for and label all unanalyzed waste buckets of this type of material to assure that no other buckets intended for process recycle have been, or will be, erroneously placed into waste drums. complete)

The SPC IIB is formally evaluating incident cause(s) and potential corrective actions.

OFFSITE NOTIFICATION REGARDING THE CAPTURE OF AN INJURED GREEN SEA TURTLE IN THE PLANT'S INTAKE NET

The following text is a portion of a facsimile received from the licensee:

"At 1137 on 11/08/00, a notification was made to the Florida Fish and Wildlife Conservation Commission regarding a live green sea turtle found in the plant's intake net. The turtle will be sent to an offsite rehabilitation facility. [...] The notification to a State Government Agency requires a notification to the NRC per 10CFR50.72(b)(2)(vi)."

The licensee stated that the turtle was apparently injured by a boat propeller before entering the plant's intake.

The licensee notified the NRC resident inspector.