ML20206R372

Insp Rept 70-1151/99-203 on 990419-23.No Violations Noted. Major Areas Inspected:Selected Potential High Risk Activities in Facility,Including Ammonium Diuranate Processing,Powder Blending,Ventilation & Solvent Extraction

ML20206R372
Person / Time
Site:	Westinghouse
Issue date:	05/14/1999
From:	NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS)
To:
Shared Package
ML20206R362	List: ML20206R372
References
70-1151-99-203, NUDOCS 9905200094
Download: ML20206R372 (13)

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U.S. NUCLEAR REGULATORY CO51 MISSION OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS Docket Number: 70-1151 License Number: SNM-1107 Report Number: 70-1151/99-203 Licensee: Westinghouse Electric Corporation Commercial Nuclear Fuel Division Location: Bluff Road Columbia, SC Inspection Dates: April 19 - 23,1999 Inspectors: Dennis Morey, Senior Criticality Safety Inspector, NRC Headquarters Frank Gee, Criticality Safety inspector, NRC Headquarters Approved By: Philip Ting, Chief Operations Branch Division of Fuel Cycle Safety and Safeguards, NMSS 1

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Enclosure i

9905200094 990514 PDR ADOCK 07001151 .

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I l l l WESTINGIIOUSE COLUMBIA FUEL FABRICATION FACILITY NRC INSPECTION REPORT l 70-1151/99-203 I EXECUTIVE

SUMMARY

Introduction The Nuclear Regulatory Commission (NRC) conducted a routine, announced nuclear criticality l safety (NCS) inspection of Westinghouse Columbia Fuel Fabrication Facility on April 19 - 23, 1999. The inspection was conducted by NRC Headquarters staff, using Inspection Procedure .

(IP) 88015. The inspection focused on selected potential high risk activities in the facility I including ammonium diuranate (A DU) processing, powder blending, ventilation, and solvent extraction. The inspectors reviewed analyses, procedures, safety limits and controls, internal ,

I reviews, the licensee Safety Margin Improvement Program (SMIP) status, and several open l items.

Results

! The inspectors identified an Unresolved Item (URI) due to failure to analyze portable high efficient particulate air (HEPA) filter units prior to use in the facility.

.- The inspectors identified a program weakness in the licensee failure to review portable IIEPA units during the preparation of the ventilation integrated safety analysis (ISA).

The inspectors determined that criticality safety analyses for three potential high risk operation areas (sintering furnace, FabricMax filter, and orange racks) examined during the inspection were adequate to bound normal operations and expected upsets.-

The inspectors determined that un overflow slot, a criticality control for the pellet room

powder feed operations, will not perform as stated. This situation is not a safety concem l because other controls provide adequate safety assurance for the affected operation.

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REPORT DETAILS 1

l 1.0 Plant Operations (88015) <

a. Scope of Insnection l ' The inspectors performed walkdowns of general plant areas to observe processes involving the highest potential criticality safety risks such as ADU processing, powder blending, l ventilation, and solvent extraction. '

b, Observations and Findines Portable Highly Efficient Particulate Air (HEPA) Filter i

During a walkdown of plant process areas, the inspectors observed a portable HEPA filter unit parked in a maintenance work area of the facility. The portable HEPA consists of a small pre-filter and HEPA filter unit with a blower and six inch diameter suction hose that is mounted on wheels for ease of movement. Facility staff acknowledged that the equipment I was not analyzed for use in the plant and stated that operations was not allowed to use the

. equipment without special authorization from criticality safety. The inspectors noted that there was no sign or other indication that the equipment was not available for use. The equipment was being controlled through the radiation work permit (RWP) process whereby a user would submit an RWP which would be screened by operations to determine what safety or technical review was required for the particular application. A facility criticality safety engineer immediately placed a danger tag on the equipment to prevent use.

In the early 1980's, the licensee purchased two portable HEPA filter units for the manufacturing automated process (MAP). When MAP was shutdown, the HEPAs became available for general use in the plant. The licensee indicated that the portable HEPAs are occasionally used for negative pressure ventilation such tent ventilation in low uranium contamination areas. The licensee indicated that the portable HEPAs were not used in areas where significant quantities of uranium were available and had not been reviewed by criticality safety. The licensee attempted to locate analysis for the portable HEPA filters (two are available) but could not locate any documentation other than the original MAP l evaluation which mentioned that ventilation was approved.

One of the two portable HEPAs has been approved for use in a non-uranium contaminated l area of the Zion defabrication project. This does not pose a criticality safety concern. The L other filter will remain out of service pending criticality safety evaluation. The licensee failure to evaluate the portable HEPA filter units prior to their use with fissile material violates license Section 6.2.5 which requires that, prior to use, a movable non-favorable geometry (NFG) container will undergo compreheraive analysis and have appropriate controls identified. The inspectors determined that immediate, effective licensee corrective l

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action to remove the portable HEPA filter unit from service and initiate analysis was suflicient to assure continued safety of operations. The inspectors also determined that the safety significance of this issue would depend upon the results of the licensee analysis. The  ;

failure to analyze the portable HEPA filter units prior to use in the facility is Unresolved l Item (URI) 70-1151/99-203-01.

1 Process Enclosure Ventilation System 1

The inspectors reviewed the licensee process for filtering process air from enclosures containing nitric acid fumes and conducted a walkdown of a licensee wet scrubber system.

The licensee system involves spraying water into process enclosure airjust prior to the air entering a venturi and cyclone scrubber. The majority of particulates are removed from the air during this process and then filtered out of the water which is then recirculated up to the venturi. The clean and dry air is passed to rooftop HEPA filter. The inspectors determined that the potential high risk portions of the ventilation process were the unsafe geometry cyclone scrubber, the water filters, and the rooflop filters.

The inspectors reviewed selected controls on the potential high risk portions of the ventilation system. The inspectors verified the controls on the cyclone scrubber which consisted of a series ofopenings so that filling the vessel with solution is not credible. The inspectors also verified the safe geometry contiguration of the water collection tanks and filters which were configured respectively into slab and cylindrical geometries.

The inspectors also reviewed selected controls for the rooftop HEPA filter units.

Subsequent to walking down the roottop HEPA filter bank 1 A/2A associated with the S2A/S2B acid fume scrubber, a wet filtration system, the inspectors reviewed the licensee procedure MCP-108104 which covers maintenance of roof-top HEPA filters. A previous reportable fuel cycle facility event involved the failure of operators to report accumulations of fissile material in a tilter due to lack ofinstruction in the filter maintenance procedures.

The inspectors determined that the licensee procedure contained specific instructions to identify, report and clean up loose uranium material when such material is found in the filter housing. The inspectors determined that the criticality safety controls for the potential high risk portions of the wet ventilation system were adequate, available and reliable.

Fitzmill Powder Accumulation The inspectors observed a redbook item, which is an internally reported deficiency, reporting an accumulation of uranium dioxide (UO2) Powder in Line 2 Fitzmill enclosure.

This occurred when the maintenance operators valved off cooling water to the mill enclosure and removed and replaced a broken feed screw in the enclosure. The maintenance operators subsequently collected 57 kilograms of powder that had accumulated in the enclosure during the maintenance activities. The criticality safety limit for2 "U is 483 kg UO 2 for a koof less than or equal to 0.94. The inspectors determined that there were no paths for water

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entry into the mill enclosure when the cooling water is double valved off. The safety limit for moderator is 179 kg of water for a k-effective ofless than or equal to 0.94. The inspectors determined that there was a sufficient margin of safety for the Fitzmill maintenance operation due to limited mass and the absence of modarator so that the powder

. accumulation did not challenge any safety limit.

c. Conclusion The inspectors identified an NCV due to failure to analyze portable HEPA filter units prior to use in the facility The inspectors determined that there was a sufficient margin of safety for the Fitzmill maintenance operation due to limited mass and the absence of moderator so that a recent powder spill did not challenge any safety limit.

2.0 Safety Margin Improvement Plan (88015)

a. Scone of Inspection The inspectors reviewed the progress of the SMIP in NCS related areas. The inspectors interviewed licensee management regarding SMIP status and reviewed selected areas based on several Inspector Followup Items (IFIs) which SMIP items are intended to resolve.

b. Observations and Findines The licensee has developed a plantwide SMIP program which is expected to result in improved compliance with license requirements and improved nuclear safety at the facility.

The inspectors reviewed the SMIP program focusin,g on resolution of selected issues raised during previous inspections. The inspectors detennined that substantial progress was being made in carrying out the program and that it would be reasonable to consolidate two items that tracked SMIP issues. IFI 70-1151/98-202-03 tracked the effectiveness of the configuration management (CM) program to support the NCS function and IFI 70-1151/98-202-01 tracked revision of RA-310 or development of procedures for independent technical review. These IFis are discussed in detail in Section 5.0. The inspectors determined that the SMIP is on schedule.

The inspectors noted during the review that the licensee has completed the ventilation portion of the ISA. Completion of the ventilation ISA was noted by the licensee as a key SMIP accomplislunent in a summary of the SMIP status. As documented in Section 1.0, the inspectors identified a significant ventilation system, the portable HEPA filters, that was in use and had not been analyzed and approved for use in the facility. The inspectors reviewed other risk significant portions of the licensee ISA without detecting a similar weakness. The inspectors noted that the principle function of the portable HEPAs for many years was the ventilation of tent enclosures although most routine uses for the equipment marks it as a

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ventilation system. The inspectors determined that the failure to review portable llEPA filter units and incorporate the results into the ventilation ISA is a potential program weakness.

. c. Conclusion The inspectors determined that the SMIP is on schedule. The inspectors identified a potential program weakness in the licensee failure to review portable HEPA units during the preparation of the ventilation ISA.

3.0 Criticality Safety Analysis (88015)

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a. Scone of Inspection The inspectors reviewed licensee analysis that supports high risk operations such as the sintering analytical furnace, Fabriemax filters, and ftssile material storage racks. The inspectors reviewed assumptions and medels to determine the adequacy of controls.

b. Observations and Findings Sintering Furnace During inspections 70-1151/98-10 and 70-1151/99-01, Region 11 inspectors questioned the l

l safety basis of the sintering furnace. The licensee has determined that criticality in the furnace is not credible due to the heat of the furnace when uranium pellets are present. The l

regional inspectors determined that removal of spilled uranium pellets from the furnace, a maintenance operation,is performed when the furnace is cooled down. The licensee L

l indict.ted that maintenance operations are analyzed separately prior to performing the work.

Licensee analysis indicates that pellets occasionally fall out of boats while inside the furnace so that they can accumulate in the furnace. The licensee believes that a significant accumulation of pellets in the furnace due to routine operation is not credible. The licensee

! arrived at this conclusion through the use of handbook data for an infinite slab of pellets.

The inspectors determined that an accumulation of pellets in a furnace that would be a criticality concern was not credible since this would require a depth of pellets through the furnace that is greater than the height of the boats. The inspectors determined that it was not credible that water could accumulate around enough pellets in the furnace to be a criticality concern due to the design of the furnace, a level tunnel open at the ends.

FabricMax Filter Holdup NRC material' control and accounting (MC&A) inspectors identified 124 kg uranium holdup in the line #3 Fabriemax filter. The inspectors reviewed the filter ISA sections and determined that a ftmdamental assumption of the system description was a maximum b

amount of 66 kg U in the filter box. The inspectors further reviewed the filter criticality safety evaluation (CSE) and determined that the licensee bounding analysis was performed on an array of filters with a three inch layer of uranium powder on the elements. The layer of powder works out to 126 kgs of powder per filter element. The result of this analysis is keff = 0.85. The inspectors determined that this result meets license requirements and the model clearly bounds the observed situation. The inaccurate assumptions in the ISA system description are a weakness that may lead to inadequate controls although the controls were adequate in this case due to extremely conservative modeling.

Orange Rack Sample Storage During inspection 70-1151/98-10, a Region II inspector questioned the practice of storing sample containers in the same rack as filled polypacks. The rack in question holds stacks of two polypacks separated by one foot spacing. Up to four filled sample containers were stored in the open spaces of the rack. The inspectors reviewed the analytical model and dete' mined that storage of the filled sample bottles as done by the licensee with four bottles at each location does not affect the safety basis of the rack due to a conservative boundary model. The rack was analyzed and controls were based upon four polypacks in each location, and in practice, only three can be in a position in the rack.

c. Conclusion The inspectors determined that criticality safety analyses for three key potential high risk operation areas (sintering furnace, FabricMax filter, and orange racks) examined during the inspection were adequate to bound normal operations and expected upsets. A weakness was identified in inaccurate ISA system description assumptions that may lead to inadequate controls although the controls were adequate due to extremely conservative modeling.

4.0 Reliability of Controls (88015)

a. Scone of Inspection The inspectors investigated the reliability of various NCS controls in potential high risk process operations such as powder feed and uranyl nitrate (UN) storage tank operations.

b. Observations and Findings Powder Feed Controls During inspection 70-1151/99-01, Region II inspectors noted a slot at the top of the bulk powder handling enclosure feed chute. The slot was determined to be safety significant in that it is intended to prevent the accumulation of water in the chute. The regional inspector observed that wet powder would most likely not go through the slot which was already

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partially blocked with powder. The inspectors noted that this safety feature (the slot) would only function as intended if water alone was present. The water would not flow through the slot as intended if powder was present in the chute. The licensee stated that two controls remain on the chute even if the slot fails because there is a level probe on the chute which will detect water level and moderator is prevented from entering the chute by barriers and moisture sampling of material up stream. The inspectors determined that the slot will not behave entirely in the fashion anticipated by the flowchart in the analysis although criticality safety of the equipment is assured by the level probe and moderator controls. Licensee management agreed to modify the criticality safety analysis for the equipment to recognize that the overflow slot was not as effective a control as the level probe and moderator controls. Licensee action to revise the criticality safety analysis will be tracked as IFl 70-1151/99-203-02.

Bulk UN Storage Tanks The inspectors conducted a walkdown of the bulk UN storage tank area. The 7500-gallon bulk UN storage tanks are large, unsafe geometry vessels. If uranium in these tanks is accidently precipitated, criticality is possible. The inspectors reviewed the process including process and instrumentation drawings and discussed the system with a criticality engineer.

Six 7500-gallon UN tanks are used to accumulate UN for feed into the ADU system. At a concentration of 5 grams *U per liter, a criticality could occur if the uranium is precipitated. Only the addition of a strong caustic solution could cause precipitation so the primary safety effort by the licensee is to prevent the introduction of caustic rolution into the tanks. The inspectors determined, by reviewing the system drawings and walking down relevant plant areas, that there were no direct connections between the UN accumulation tanks and any system containing caustic so!ution. The inspectors also determined that licensee controls requiring sampling of material prior to transfer into the UN tanks were adequate to prevent transfer of sufficient material to cause a criticality event.

c. Conclusion The inspectors determined that an overflow slot, a criticality control for the pellet room powder feed operations, will not perform as stated. This situation is not a safety concern because other controls provide adequate safety assurance for the affected operation. The licensee agreed to modify the equipment analysis to reflect the limitation of the control.

5.0 Open Item Review (88015,92701)

IFI 70-1151/96-204-07: This item tracked the development of guidance for reporting criticality safety vinlations to the Criticality Safety Function. The licensee has prepared detailed guidance mr identifying and reporting criticality safety issues along with a training program to implement the policy. The inspectors reviewed the licensee training materials to determine whether the reporting criteria was adequate to assure that significant criticality 1

safety issues are reported to the criticality safety function for evaluation. Licensee reporting criteria for operations staffis based on a detailed flowchart which is presented to employees during training. The inspectors determined that the licensee flowchart constituted adequate guidance for identification and reporting of criticality safety concerns to the criticality safety function for evaluation. This item is closed.

VIO 70-1151/97-205-06: This item concerned the licensee's failure to report an event as required by the license. The licensee was cited for an untimely report of events to NRC in

. June and August 1997, on the granulator hopper and the pellet area ventilation system moisture dropout tank volume. The licensee revised procedures, RA-111," Safety Significant Incident Investigations," and RA-107, " Internal Reporting, & NRC Notification of Unusual Occurrences," in 1997 and completed and issued consequence basis fault tree and trained all affected personnel in the aforementioned procedures. The inspectors determined that the corrective actions by the licensee adequate. This item is closed.

IFI 70-1151/98-202-01: This item tracked revision of RA-310 or development of procedures for independent technical review. This item is adequately tracked by IFI 70-1151/98-202-02 which tracks adequacy of SMIP implementation. Independent technical review is part of overall SMIP activity. This item is closed.

IFI 70-1151/98-202-02: This item tracked the adequacy of NCS SMIP item implementation.

This item remains open.

IFI 70-1151/98-202-03: This item tracked the effectiveness of the CM program to support the NCS function. This item is adequately tracked by IFI 70-1151/98-203-02 which tracks scheduled improvements to the licensee configuration management program. This item is  ;

closed.

IFI 70-1151/98-204-01: This item tracked event reporting criteria. The licensee has scheduled to complete the item on April 30,1999. This item remains open.

IFI 70-1151/98-204-02: This item tracked licensee efforts to upgrade the validation report.

The inspectors had determined that the licensee did not have a site-specific validation report for KENO; however, the elements of a site-specific validation report appeared to exist in other documents located both off-site and at the Columbia plant. Since the inspection, the licensee has developed a site-specific validation report as Chapter 5 in the criticality safety handbook, " Handbook for the Conduct of Nuclear Criticality Safety Activities at the Columbia Fuel Fabrication Facility," Revision 0, March 1999. In this inspection, the inspectors reviewed the handbook and found the chapter on validation adequate. This item is closed.

IFI 70-1151/98-10-01: This item tracked resolution of analytical issues regarding storage of samples in the orange fissile matdrial storage rack and the use of cracked pellet boats in the

r sintering fumace. The inspectors determmed that sample storage in the orange rack is I bounded by criticality analysis. Analytical concerns surrounding the use of cracked boats are resolved by the discussion of the credibility of criticality in the furnace This item is closed.

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IFI 70-1151/99-01-01: This item concerned the analysis of moderator in the sintering i furnace, specifically the licensee assertion that criticality in the sintering fumace is not credible. Inspectors determined that accumulation of moderator and pellets in the furnace is not credible. This item is closed.

l IFI 70-1151/99-01-02: This item concerned the reliability of the overflow slot in the pelleting area powder feed funnel as an engineered safety feature. The licensee has agreed to modify criticality analysis to reflect the limitations of this control. This item is closed.

i 6.0 Slanagement Sleetings I

The inspectors presented the inspection scope and results to members of the licensee's i management and staff during the April 23,1999, exit meeting. One IFl was identified and one l was closed. The licensee acknowledged and understood the findings as presented. The inspectors conducted a re-exit meeting with licensee management on April 30,1999, to discuss i I

an issue not included in the April 23.1999, exit meeting, the potential weakness in the ISA review of the ventilation. system.

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-1l-Partial List of Persons Contacteu i

Licensee  !

• J. Allen, Plant Manager

• D. Colwell, Measurement Control

• R. Ervin, Technical Services l

• D. Goldbach, Chemical Operations Manager

• J. Heath, Regulatory Manager

• E. Keelen, Product Assurance Manager ,

• N. Kent, Regulatory Affairs (NCS Technical Support) /

• J. Harrison, Engineering Chemistry Laboratory

• D. Williams, Regulatory Affairs Advisory Engineer NRC

• F. Gee, Criticality inspector, Headquarters

• D. Morey, Senior Criticality Inspector, Headquarters

• W. Smith, Physical Scientist, Headquarters

• D. Whaley, Physical Scientist, Headquarters

• Indicates those attending the exit meeting on April 23,1999 Insnection Procedures Used Headquarters Nuclear Criticality Safety Program IP 88015 Review of Previously Identified Followup Items IP 92701 List of items Onened. Closed, and Discussed l

l Items Onened Concerns licensee failure to analyze portable HEPA filter units URI 70-1151/99-203-01 use at the facility.

Tracks licensee action to revise analysis of the pelleting area IFl 70-1151/99-203-02 powder feed funnel slots to reflect the relative weakness I Control.

Items Closed Tracked the development of guidance for reporting criticality IFI 70-1151/96-204-07 safety violations to the Criticality Safety Function.

VIO 70-1151/97-205-06 Concerned timely reporting of events to NRC.

I IFl 70-1151/98-202-01 Tracked the revision of RA-310.

IFI 70-1151/98-202-03 Tracked the effectiveness of the CM program to support the NCS j function.

IFI 70-1151/98-204-02 Tracked the licensee effbrts to upgrade the validation report.

IFI 70-1151/98-10-01 Tracked resolution of analytical issues for storage racks and furnace boats.

IFl 70-1151/ 99-01-01 Tracked resolution of analytical issues for the sintering furnace.

IFl 701151/99-01-02 Tracked resolution of overflow slot adequacy.

Discussed IFI 70-1151/98-202-02 Tracked the adequacy of NCS SMIP item implementation.

I IFI 70-1151/98-204-01 Tracked event reporting criteria.

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I I ist of Acronyms Used l

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ADU Ammonium Diuranate CM Configuration Management CSE Criticality Safety Evaluation IFI Inspector Followup Item ISA Integrated Safety Analysis MAP Manufacturing Automated Process l

MC&A Material Control and Accounting NCS Nuclear Criticality Safety NFG Non-Favorable Geometry NRC Nuclear Regulatory Commission I IIEPA Ilighly Efficient Particulate Air l RWP Radiation Work Permit SMIP Safety Margin Improvement Plan l UN Uranyl Nitrate UO 2 Uranium Dioxide 2"U Uranium 235 URI Unresolved Item l

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