ML20059D104
| ML20059D104 | |
| Person / Time | |
|---|---|
| Site: | 07000734 |
| Issue date: | 10/06/1993 |
| From: | Brewer R, Hooker C, Reese J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML20059D096 | List: |
| References | |
| 70-0734-93-06, 70-734-93-6, NUDOCS 9311020136 | |
| Download: ML20059D104 (10) | |
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U. S. NUCLEAR REGULATORY COMMISSION REGION V b
Report No. 70-734/93-06 Docket No.70-734 License No. SNM-696 Licensee: General Atomics P. O. Box 85608 San Diego, California 92186-9784 Facility Name: Torrey Pines Mesa and Sorrento Valley Sites Inspection at:
San Diego, California Inspection Conducted: September 13-17, 1993
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Date Signed Inspector:
C. A. Hgoker, Fuel Facilities Inspector V! (m ;
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Date Si ned 10 Specialist R( s.'E rey /er, R
/# *D Approved by: /
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Dat6 Signed Jges li.Reese, C) fief
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e acilities Radiological Protection Branch Summary:
This was a routine unannounced inspection of criticality Areas Insoected:
safety, operations review, operator training / qualification, maintenance / surveillance testing, and followup on open items from previous The inspection also included a review of the inspection findings.
circumstances surrounding a minor hydrogen explosion in a furnace at the TRIGA Fuel Fabrication Facility.
Inspection procedures 30703, 88015, 88020, 88010, 88025, 93702, 92702, and 92701 were addressed.
In the areas inspected, two non-cited violations (NCVs) were Results:
(1) exceeding an administrative U-235 mass limit identified that involved:
(Section 2.0), and (2) failure to follow operating procedures (Section 2.1),
The licensee's timely actions relative to the NCV's were indicative of managements concern to assure that identified problems were adequately evaluated and corrected to prevent recurrence.
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9311020136 931014 PDR-ADOCK 07000734-
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DETAILS 1.0 Persons Contacted General Atomics (GA)
- R. N. Rademacher, Vice President, Human Resources
- K. E. Asmussen, Director, Licensing, Safety and Nuclear Compliance B. E. Thurgood, Director TRIGA Group V. Malakhof, Manager, Nuclear Safety
- J. Yi, Deputy Manager, Nuclear Safety
- R. W. Schlicht, Manager, TRIGA Programs
- R. K. Kruger, Manager, TRIGA Fuel Fabrication C. L. Wisham, Manager, Nuclear Materials Accountability J. J. Saurwein, Manager, Fuel Quality Control
- H. Dunlap, Manager, Quality Systems
- L. R. Quintana, Manager, Health Physics
- S. P. Massey, Senior Engineer, Quality Assurance
- W. T. Stowe, Security Chief
- B. Laney, Licensing NRC Personnel R. E. Wilson, Project Manager, Licensing Branch, Fuel Cycle and Safeguards Division, NMSS
- Denotes those attending the exit interview on September 17, 1993.
In addition to the individuals noted above, the inspectors met and held discussions with other members of the licensee's staff.
In the following sections of this report, the singular use of the word
" inspector" indicates that only one inspector was involved in the specific area, and the plural use " inspectors" indicates that more that one inspector shared involvement in the specific area.
2.0 criticality Safety and Operations Review (88015 and 88020)
The licensee's program was reviewed for compliance with the recuirements of 10 CFR Part 70, License Conditions, licensee procedures, anc, recommendations outlined in various industry standards and to verify that operations were being conducted to ensure the safety of the general public and facility workers.
inspection Report No. 70-734/93-01 describes previous inspection activities in this area.
Regarding changes, the inspector noted that the licensee had added a new criticality safety analyst to their staff. This new individual holds the position of Deputy Manager, Nuclear Criticality Safety and was performing criticality safety analyses (CSAs) under the supervision of Criticality Safety.
Based on a review of the new the Manager, Nuclear individuals resume, the inspector did not identify any concerns related to his qualifications for the tasks he was performing.
The inspectors toured selected facilities to observe current operations
2 and criticality controls. There have been no new processing operations involving special nuclear material (SNM) requiring a CSA during the past year.
Revised CSAs related to the licensee's CSA update program are discussed in Section 5.2 below.
Current activities in the Sorrento Valley Building 39 (SVB) involved the use of natural and depleted uranium. This operation was currently limited to a safe batch limit of 350 grams (93 % U-235).
Based on observations of activities in progress and the review of facility inventory records, the inspector observed that no accountable SNM was present.
On September 14, 1993, at about 12:00 pm during a tour of the Fuel Quality Control Laboratory (FQCL) located in SVB, the inspector noted that the SNM inventory record for the D2-112 Station of this facility evidenced the presence-of 407 grams of U-235 which exceeded its administrative mass limit of 350 grams U-235. The inspector brought-this matte to the attention of the laboratory person present who immediatr 3 'aformed the manager of the facility.
Immediately following-veri fica t if the SNM indicated on the inventory record, the facilit.y uanager notified the Manager, Nuclear Safety. Without delay, the licensee made arrangements to reduced the Station D2-112 inventory to less than 350 grams U-235 and initiated an investigation of the matter. The licensee transferred 63 grams U-235 from the D2-112 station to other authorized locations which reduced D2-112 station's SNM inventory to 344 grams U-235. The licensee's investigation determined that:
(1)
Due to a lack of 6dequate communication, at about 10:00 am on September 14, 1993, more SNM than requested by the FQCL was transferred from the licensee's main storage vault to the D2-112 station. The FQCL had requested specific samples of a known SNM -
quanti ty. The samples were stored in more than one storage container which Liso contained other samples not involved in the request. When the transfer was made, the containers and total contents (more samples than requested with a total of 99 grams U-235) were transferred to the FQCL D2-112 station which contained 308 grams U-235.
(2)
The incident was not reportable to the NRC Operations Officer in accordance with GA's procedures submitted to the NRC in response to NRC Bulletin 91-01, dated October 18, 1991.
The licensee initiated the following corrective actions to prevent recurrence:
(1) the attendance of all FQCL personnel at a criticality annual refresher training on September 15, 1993, (2) mandatory review of GA's SNM material transfer manual by the SNM custodians,
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' revision of.the FQCL WA procedures to include the requirements (3) contained in GA's material transfer manual, and revise the FQCL SNM inventory sheets to include station limits at (4) the top of the page.
Condition No. 9 of License No. SNM-696 authorizes the use of license r
materials in accordance with the statements, representations, and conditions contained in Part II, " License Specifications," dated July 24, 1981, and supplements dated March IE, 1982, through June 15, 1992.
Section 3.2.1, " Operating Groups," Part II of the license specifications requires that the manager or designee shall ensure that' conduct of activities within the area is in compliance with all applicable criteria, rules and practices as set forth in Werk Authorizations (WAs).
Section 3.4.1, " Procedure for Approval of Work Authorizations," Part II of the license specifications requires compliance with all procedures for radiological safety, criticality, material accountability and Also, it requires that control, and physical protection requirements.
other safety related features of the work, such as structural integrity, potential of fire or explosion and the like, are adequately considered and suitable provisions have been incorporated.
Section 4.1.1 of procedure No. F0QI-23-16, "SNM Control Within the Fuel Quality Control Laboratory," approved with the FQCL's WA No. 2971, limits the D2-112 station to 350 grams U-235.
Exceeding the SNM mass limit of the D2-112 station was identified as a violation of License Condition No. 9.
However, this NRC identified violation will not be cited because the criteria in Section VII.B. of the Enforcement Policy were satisfied (NCV 70-734/93-06-01).
s 2.1 Hydride Furnace Event - TFFF The inspector toured the facility, interviewed cognizant licensee personnel, and reviewed the licensee's investigation of thecir explosion that occurred in the hydride furnace at the TFFF on Augm 16, 1993.
2.1.1 Summary of Event The manufacture of TRIGA fuel involves the mixing of uranium metal with 1
zirconium metal using melting, casting, and standard machining Alloyed (U/Zr) castings are machined to the desired fuel size and then processed through a hydride furnace to obtain a specified processes.
The furnace has an inside diameter of about 6 inches with H/Zr ratio.
an overall length of about 12 feet and the effective fuel loading length TRIGA fuel normally fabricated at this facility is of about 9 feet.
The criticality safety analyses and j
slightly less than 20% U-235.
limits for operations in the facility are based on uranium enriched to
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1 93% U-235.
The operating staff at this facility consists of a-facility manager, two fabrication technicians, and a quality control (QC) inspector. The QC inspector verifies certain process steps and inspects product quality.
All of these individuals have several years experience at this facility.
At about 3:00 pm on August 13, 1993, a fuel hydriding process had been completed and the furnace was left on an automatic shutoff cooling cycle over the weekend. The U/Zr fuel inside of the furnace contained about 1.3 kilograms of U-235. At approximately 7:00 am on August 16, 1993, with the furnace cooled down to about 30 degrees celsius, an operator prepared to unload the hydrided fuel. The operator observed that there was a residual pressure of 5 to 7 pounds per square inch gauge (p.s.i.g.) inside the furnace. The operator then evacuated the furnace to O p.s.i.g., removed the furnace chamber flange and left the area to obtain equipment to remove the fuel boats from the furnace.
Approximately 30 seconds from the time the operator opened the furnace, an explosion occurred within the furnace.
Immediately following the explosion, the operator who had opened the furnace and the other TFFF personnel in the facility assembled near the furnace and observed that the fuel (0.5 inch U/Zr machined rods) in the
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furnace boats were sparking. No physical daniage to the inside or outside of the furnace or water leakage from the external cooling system of the furnace were observed by the TFFF personnel. The operators immediately sealed the furnace by re-installing the flange and pressurized the furnace to about 10 p.s.i.g. with helium. No further disturbances occurred.
Also immediately following the explosion, the TFFF personnel made several calls to summon a health physics technician (HPT) to survey the facility. Due to the time of day and personnel being on vacation, a HPT did not arrive at the facility until about 9:00 am. The TFFF's manager arrived at the facility at about 9:30 am (normal work schedule start time). The Manager, Nuclear Safety who was informed of the event by the Health Physics manager at 9:45 am arrived at the TFFF at approximately 9:50 am to evaluate the criticality safety consequences of the event.
At approximately 10:35 am the licensee informed an NRC inspector who was onsite conducting a non-related inspection. Additionally, the event was discussed with the NRC Region V office.
2.1.2 Licensee's Investiaation Based on a physical inspection of the furnace and contents (fuel), the Manager, Nuclear Criticality Safety determined that no criticality controls had been lost or significantly degraded as there was no flooding of the furnace, or loss of geometry, and the fuel remained intact. The licensee determined, in accordance with procedures established in response to NRC Bulletin 91-01, that the event was not reportable to the NRC Operations Officer. The licensee's investigation also deterniined that:
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5 (1)
The residual hydrogen mixed with air when the furnace was opened, and that the surface of this particular fuel was uncharacteristically hydrided which made it unstable and prone to spontaneous sparking. The sparking fuel supplied the ignition source for the hydrogen gas mixture inside of the furnace.
(2)
Prior to opening the furnace, the operator failed to recognize that the residual pressure was hydrogen and this individual also failed to follow established operating procedures for opening the furnace following hydriding.
Sections 5.0 through 5.2 of operating procedure No. 8, "Hydriding," approved January 26, 1993, with the TRIGA Fuel Fabrication Facility's (TFFF) WA, No. 2962 require that the hydrogen control system be checked to ensure that all valves are closed to the hydriding furnace and that the furnace be pumped down to 30 inches of vacuum and back-filled to atmospheric pressure (0 p.s.i.g.) with helium before opening the furnace for fuel unloading.
(3)
Internal reporting of the event to the Nuclear Safety department was not timely in accordance with established internal guidance.
However, had the event been reportable to the NRC Operations Officer, the notification would have been within the required reporting time frame.
(4)
No personnel contamination was detected and nasal smears of the personnel involved indicated no potential for intakes of radioactive materials. The licensee collected urine samples from these individuals and sont them to their offsite contract laboratory for analysis. Lung counts were also schedule daring the next (late September 1993) routine vendor supplied mobile lung counting service.
The radiological surveys indicated that the explosion rouited in local floor contamination of 100 - 150 disintegrations per minute per 100 square centimeters alpha. A fixed air sample located above the furnace opening also indicated that the air activity from the event was at about 60% of the 10 CFR Part 20, Appendix B, Table I limit for insoluble uranium.
2.1.3 Licensee's Corrective Actions The inspector verified the following corrective actions taken by the licensee:
(1)
Radiation safety / nuclear safety refresher training were given to all of the TFFF personnel on August 18, 1993, with particular emphasis given on prompt reporting of all upset conditions involving SNM.
(2)
Although the operating procedure for the hydride furnace
6 delineated the necessary steps to be taken when opening the furnace, the licensee believed that more explicit step by step details were needed to assure that a similar' event would not occur in the future. The operating procedure was revised to include more detailed step by step safety instructions and notification of the supervisor / manager of the facility when upset conditions occur.
(3)
The working hours of the TFFF's manger were changed to coincide with the working hours of the operating staff.
(4)
The licensee took what they deemed to be appropriate disciplinary action for the operator who failed to follow proper procedures when he opened the furnace.
Based on the review of the licensee's investigation and licensee procedures, discussions with cognizant licensee personnel and observations of the furnace during facility tours, the inspector determined that the licensee had adequately evaluated and implemented corrective actions to prevent recurrence of a similar event. The inspector also determined that failure of the operator to follow the operating procedure for opening the furnace was a violation of License Condition No. 9.
However, this violation will not be cited because the criteria in Section VII.B. of the Enforcement Policy were satisfied (NCV -
70-734/93-06-02).
The licensee's performance in this area indicated that operating personnel need to pay more attention to detail when operating equipment-that can result in upset conditions, and during transfers and receipt of SNM. The licensee's actions related to the hydride furnace event and the SNM over limit in the FQCL D2-112 station were indicative of
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managements concern to assure that identified problems were adequately evaluated and corrected to prevent recurrence.
Two NCVs were identified.
3.0 Operator Trainino/0ualification (88010) i Section 2.1.5 of NRC Inspection Report No. 70-734/93-01 describes previous inspection efforts of this area. During this inspection (70-734/93-06), the inspector attended an annual nuclear safety refresher training class that followed the licensee's annual radiological safety refresher training. The class room instructions for the nuclear safety training were given by the Manager, Nuclear Criticality Safety. The class consisted of about 50 employees from various crafts, HP staff, laboratory personnel, and supervisory and management personnel. The instructions included basic nuclear theory, consequences of criticality accidents, controls and limits to prevent criticality accidents, and internal reporting requirements (highly emphasized) when upset conditions involving SNM occur. This-one hour lecture was followed by a test to evaluate the employees knowledge of the training provided. A review of selected graded tests indicated that the employees had an -
adequate understanding of the instructions provided in the class.
Based t
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7 on interviews with personnel during facility tours, the inspector. did not identify any individual that appeared to be unqualified for the tasks being performed.
The licensee's' performance in this area appeared adequate and their program appeared capable of accomplishing its safety objectives.
No violations or deviations were identified.
4.0 Maintenance and Surveillance Testina (88025)
The inspector reviewed _the licensees maintenance and surveillance testing program for compliance with applicable regulations, ' license specifications and licensee procedures. Maintenance and surveillance -
testing of the Hydride and 0xide Fines Burn Furnaces at the TRIGA Fuel Fabrication Facility, and the criticality monitoring system at the Triga Fuel Fabrication Facility and Building 41 Vault were examined. The following licensee procedures were reviewed during this portion of the inspection.
TRIGA Fuel Fabrication Operating Procedure for Hydriding, Operation No. 8, Issue A, December 4,1990.
TRIGA Fuel Fabrication Operating Procedure for Hydriding, Operation No. 8, Issue B, August 30, 1993.
TRIGA Fuel Fabrication Operating Procedure for Oxide Fines Burning Furnace, Operation No.10, Issue B, March 3,1993.
NCP-2-A, Procedure for Criticality Alarm System Testing: Main Site, SVB, and Waste Yard, January 23, 1992.
NCP-219-A, Calibration Procedure for Eberline RMS II Radiation Monitoring System, January 23, 1992.
The inspector noted that the licensee's procedures adequately addressed i
applicable regulatory and license specification requirements. The inspector verified that the licensee was adequately performing the required maintenance and surveillance tests by reviewing various records, interviewing licensee personnel and conducting facility tours.
1 The licensee's maintenance and surveillance testing program appeared adequate to meet its intended safety objectives. No violations or deviations were identified.
5.0 Followuo - Licensee Action on Previous Inspection Findina 5.1 Cited Violations (92702)
Based on a review of new CSAs: (1) " Nuclear Safety Re-Evaluation of the TRIGA Fuel Fab Facility," dated July 8,1993, and Revised September 3, 1993, and {2) " Nuclear Safety Evaluation of Casting Furnace," dated February 1,1993; and the review of additional training and guidance
8 provided to employees regarding NRC reporting requirement, the inspector verified the corrective actions taken and those to prevent recurrence for the following violations as stated in the licensee's timely response dated March 18, 1993.
(1) 70-734/93-01-01 (Closed) - Failure to Maintain Records of CSAs (2) 70-734/93-01-02 (Closed) - Failure to Evaluate all Credible, Accidents (3) 70-734/93-01-03 (Closed) - Failure to Provide the Calculated K,ff Value in CSAs (4) 70-734/93-01-04 (Closed) - Failure to Timely Report an Event to the NRC 5.2 Inspector Followuo items (92701) 70-734/91-04-01 (Closed) - Adeouacy of bioassay Procedures This item involved the need for the licensee to review the adequacy of their bioassay investigation levels for uranium.
Based on a review of the licensee's revised bioassay procedure, " Interpretation of U-235 Bioassay and Lung Count Results," dated September 17, 1993, the inspector determint.d that the licensee had adequately incorporated appropriate investigation levels relative to their frequency for bioassay measurements. The inspector had no further questions regarding this matter.
70-734/93-01-06 (0 pen) - CSA Update Program Section 5.0 of Inspection Report No. 70-734/93-01 describes the licensee's commitment to review the adequacy of all active CSAs.
Based on the review of CSAs " Nuclear Safety Re-Evaluation of the TRIGA Fuel Fab Facility," dated July 8, 1993, and Revised September 3, 1993, and (2) " Nuclear Safety Evaluation of Casting Furnace," dated February 1, 1993, the inspector determined that these CSAs adequately described the technical basis for assumptions, accident conditions, required design featurcs and judgements on double contingency.
Due to the limited operations involving SNM, the licensee expects to complete their update program by the end of 1993.
Section 5.6, " Equipment Integrity," Part II of the license application requires that structures, equipment and containers that directly effect -
criticality control shall be adequately designed to assure criticality control during and-after an earthquake of a Mercalli Magnitude VIII (about equivalent to a Richter Magnitude 6.5).
During a the review of CSAs, the inspector noted the CSA file for the main site SNM storage vault did not contain any data or reference as to its seismic design or contingencies related to earthquakes.
Prior to the end of the inspection, the licensee provided the inspector with engineering data to
9 support the license requirement.- The Director, Licensing, Safety and Nuclear Compliance acknowledged that the CSA for the SMM vault needed to reference seismic design criteria and include contingencies related to seismic events, and stated-that these matters would-be addressed in The effectiveness of -
applicable CSAs' as part of the CSA update program.
the licensee's CSA update program will be review in a subsequent inspection.
6.0 Exit interview (30703)
The inspection scope and findings were summarized with the individuals denoted in Section 1.0 on September 17, 1993.
The licensee was informed of the two NCVs described in the report.
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