ML20138H921

Insp Rept 70-0036/97-202 on 970331-0402.No Violations Noted. Major Areas Inspected:Inspectors Toured Facility Bulk Chemical Storage Areas & Reviewed Potassium Hydroxide Neutralization Sys Involved in August 1996 Reactor Event

ML20138H921
Person / Time
Site:	07000036
Issue date:	05/02/1997
From:	NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS)
To:
Shared Package
ML20138H907	List: ML20138H903 ML20138H921
References
70-0036-97-202, 70-36-97-202, NUDOCS 9705070326
Download: ML20138H921 (7)

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U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS l  !

Docket No.: 70-36 License No.: SNM-33 Report No.: 70-36/97-202 Licensee: ABB-Combustion Engineering, Inc.

Location: 3300 State Road P l

~ Hematite, MO 63047 Dates: March 31 - April 2,1997 l Inspectors: Garrett Smith, inspector, NRC Headquarters j William Troskoski, inspector, NRC Headquarters 1

Approved By: Philip Ting, Chief I

Operations Branch Division of Fuel Cycle Safety and Safeguards, NMSS I

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j Enclosure i

11 9705070326 970502 PDR ADOCK 07000036 PDR a

L. l l i EXECUTIVE

SUMMARY

l ABB-COMBUSTION ENGINEERING,INC.  !

NRC INSPECTION REPORT l

! 70-36/97-202 i i

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1.0 inspection Summarv l

Areas inspected NRC performed a reactive, unannounced chemical safety inspection of the ABB-Combustion Engineering facility in Hematite, Missouri, on March 31 - April 2,1997.

The inspection focused on gathering information regarding the possible hydrofluoric acid (HF) exposure of a plant employee and an NRC material control and accounting (MC&A) inspector on March 26,1997. Specifically, the inspectors established the sequence of circumstances surrounding this event, and reviewed the HF dry scrubber system, as well as associated safety systems.

1 Additionally, the inspectors toured the facility's bulk chemical storage areas and reviewed l the potassium hydroxide (KOH) neutralization system that was involved in the August 1996 chemical reaction event that resulted in an Augmented Inspection Team (AIT).

Results

1. A NRC inspector and one licensee employee may have been exposed to fugitive HF emissions from the dry scrubber system on March 26,1997. Several similar events typically occur over the course of a year, due to system leaks or atmospheric ,

inversions affecting stack releases. Management has previously recognized the i problems related to the dry scrubber system and planned modifications to go to a

" wet" scrubber system by the end of 1997 are expected to significantly limit future HF emissions.

2. The licensee has not developed a formal method to identify equipment and components that are " safety-related" and "important-to-safety," although these terms are used in various licensee procedures and documents, including regulatory submittals. Furthermo're, no guidance exists as to how plant personnel should  !

handle such equipment or components with regard to operability and reliability,

'when compared to commercial grade items.

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DETAILS 2.0 Possible Personnel HF Exoosure

a. Scooe On March 27,1997, FCOB rnanagement was notified by an NRC MC&A Inspector that the inspector and a licensee employee had potentially been exposed to HF fumes while performing an inspection at the CE Hematite facility. The inspectors reviewed the circumstances surrounding this event.

b. Observations and Findinas Descriotion of Event On March 26,1997, between the hours of 9:30 and 11:30 a.m., an NRC inspector and an ABB-CE Nuclear Material Measurement and Accountability (NMMA)

Specialist were performing an items-on-hand verification to locate selected UF, cylinders. More than once during the verification the ABB-CE employee asked whether the NRC inspector had smelled HF, and the inspector had not. A few moments later (while still outside) the NRC inspector felt a burning sensation in her nose and throat, but did not notify the licensee employee. The inspector and the NMMA specialist then proceeded to the rod-line. While at the rod-line, the NMMA specialist started becoming nauseous. At this time they stopped for lunch, and the NMMA specialist notified his management that he was ill and wanted to go home.

During an interview with him, he stated that he felt he had the flu and that his I symptoms were not related to the HF that he had smelled earlier.

The next morning, the NRC inspector noticed that her nose and throat were irritated  !

and notified line management. After licensee management was notified, the  ;

inspector was examined by the plant physician at Jefferson Memorial Hospital in j Festus, Missouri. The physician concluded that the inspector had a minor nose '

irritation from possible HF fume exposure. The inspector received a Certificate of

Fitness and returned to work. The NMMA specialist returned 1. vork the next l morning and stated that he felt fine.

The inspectors interviewed the NMMA specialist, who felt that although he did l smell HF at the time, the " illness" that he experienced later in the afternoon was not associated with his exposure.

Licensee Management indicated that the HF smell probably came from the main process stack due to atmospheric conditions. Process gases are treated with a dry scrubber to remove HF prior to release. Licensee documents indicated that the

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effluent released from this elevated point is approximately 100 ppm HF. Licensee i management also indicated that when the wind shifts, low concentrations of HF could be smelled in the cylinder yard.

Drv Scrubber Eauioment Descriotion ABB-CE uses the dry process to convert UF. to UO2 . During this type of conversion, steam is introduced to hydrolyze the UF., As a result of this reaction, UO,F and HF are formed. A dry scrubber system is used to treat the HF prior to releasing the process gasses out the stack by reacting it with limestone. 'This reaction forms carbon dioxide, calcium fluoride, and water per the following  ;

reaction: l CACO + 2.HF -> CaF 2 + CO2+HO 2 The dry scrubber is only about 92 percent efficient, and the effluent stream of the scrubber contains approximately 100 ppm HF.

The dry scrubber system is carbon steel. Two heating systems are used to maintain the temperature of the air and all equipment that comes in contact with the HF at about 250 degrees F. This helps to ensure that the water in the process gas will not condense with the HF gas to form liquid HF. The formation of liquid HF would severely corrode the carbon steel system. The system maintenance and operations ,

are very labor intensive. The corrosive nature of the gas deteriorates gaskets and

• l valve seats and seals rapidly. Additionally, the limestone /CaF, " rocks" need to be ,

i replaced on almost a daily schedule.

In addition to the stack releases of HF, the licensee reported that many times during l the history of the dry scrubber, the corrosion has caused fugitive releases of HF. ,

Although these releases have been greatly reduced by the use of a new gasket material, fugitive releases of HF do still occur.

During the inspection, CE personnel performed an HF level test in the area near the dry scrubbers. The " drager" type tubes indicated no measurable HF was in the area. The inspectors were informed that a similar test would be done if anyone l smelled HF in this area. '

l Drv Scrubber Historv l In 1994, the existing dry scrubber system was replaced with the carbon steel I

system that is in use today. An Integrated Safety Report was completed for this I dry scrubber system on August 28,1993. This report described the dry scrubber ]

system and identified " safety-related equipment". The report indicated that the i temperature indicators on the scrubbers measure in three locations along the vessel and one location at the outlet of each vessel. The top and middle indicator of each scrubber vessel was defined as safety related, since a failure of these indicators l may result in an increased release of HF to the environment. Additionally,17 l

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control valves were also defined as safety related, because true valve position indication assures that the off gas valves are closed while the scrubber is being filled. All of this equipment was defined as Class 2 Safety Related Equipment (SRE), because of the potential environmental impacts.

The report also indicated that prestart testing had been completed prior to startup and that tests must be done after any equipment or interlock modification to be sure that the system operates as intended.

In the July 27,1995, evaluation of their safety program against NRC Branch Technical Position (BTP) guidance, CE stated that their license application contains a  !

commitment to perform hazard analyses for the facility. Additionally, the letter  !

states that the guidance of the BTP on Requirements for Operation will be '

considered as part of the hazard analysis. Based on the guidance provided in this j B fP, the hazard analysis should review the need for calibration, maintenance, and i performance of all systems employed for achieving nuclear criticality safety, I radiation safety, process safety, and confinement of radioactive or other hazardous materials. Specifically, the July 27,1995, evaluation ~ stated that the following will i be included in hazard a'nalyses for equipment "important to safety":

1) operational parameters important to safety, and limiting specifications for these parameters;  ;

2) documentation of the basis for important-to-safety requirements for operation; and

3) programs for testing, calibration, and inspection of allinstrumentation and control systems important to safety to assure their reliability.

On March 27,1996, CE completed the integrated safety analysis (ISA) for the oxide conversion plant which includes the dry scrubber system. This ISA was the first one completed by ABB-CE as required by their license. Based on conversations with ISA team members, the team was aware of the BTP guidance, but it was not clear how or if it applied to the dry scrubber. Therefore, this new document no longer defined any of the equipment associated with the scrubber as safety related, but did describe two operational parameters important to chemical safety.

There is currently no NRC-approved guidance defining the format or content of an ISA, particularly definitions for " safety related" or "important to safety". Plant procedure NIS 216, " Hazard Evaluation," has been developed to provide internal guidance on the content of Hazard Evaluations. Although NIS 216 clearly states that the guidance in the BTP for "important to safety" will be included in hazard evaluations, the threshold of what would be considered important to safety has not been clearly defined. The licensee agreed that the terms " safety-related" and "important to safety" need to be formally defined. The Director of Regulatory Affairs took this item as an action during the exit, and its completion will be tracked as inspector Follow-up Item (IFI) No. 97-202-01.

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6-The existing dry scrubber system is scheduled to be replaced with a new wet  !

l scrubber system. The engineering design for this system is ongoing, and interviews >

l with licensee personnel indicate that the system may be installed and operating  ;

l during the last quarter of 1997. After the appropriate regulatory requirements are i met, the new system is expected to be 99.5-percent efficient in its removal of HF,  :

l and it will produce hydrofluoric acid that the licensee plans to sell as a byproduct. '!

Additionally, the plant personnel indicated that a Hazard Analysis will be completed j on this new scrubber prior to its operation. The completion and review of this Hazard Analysis will be tracked as IFl No. 97-202-02.

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c. Conclusions l

The maintenance and operation of the existing dry scrubber system is very labor intensive. Because of the harsh nature of the effluent stream, the system requires almost constant maintenance to replace gaskets and valve seats and seals.

Additionally, the system requires almost daily changeout of the " rocks" when the system is operating. Based on conversations with plant personnel, this changeout  !

l is difficult. The existing system is also only approximately 92 percent efficient.

This efficiency equated to the release of almost 10 tons of HF per year, and an HF j- concentration of almost 100 ppm in the stack effluent.

Because of these release rates, the licensee indicated that smelling HF was common

in the outside area around the dry scrubbers, but that residual health effects have l never been reported.

l 3.0 Plant Tour

a. Sggp_g

The inspectors toured the plant area, concentrating on the use and storage of L chemicals. Additionally, the inspectors toured the KOH neutralization system that was involved in the August 1996 chemical fire that resulted in an AIT.

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b. Observation and Findinas  !

The inspectors noted that the material condition of the evaporator system has been I greatly improved. The acid and base chemical systems have been separated, and l the components, piping, and valves labeled. The inspectors also noted that the ,

system modifications committed to by the licensee appeared to be adequately )

l implemented. No concerns were identified.

C. Conclusions

! The licensee has addressed the evaporator system hardware changes in accordance

with their regulatory commitments.

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MANAGEMENT MEETINGS i l

Exit Meetina Summary I Inspectors met with CE management throughout the inspection. An exit meeting was held I

on April 2,1997. No classified or proprietary information was identified. The following is a partiallist of exit meeting attendees:

ABB Combustion Enaineerina i l

H. Eskridge, Senior Consultant l K. Hayes, industrial Safety Engineer l

B. Kaiser, Vice President for Fuel Operations  :

R. Land, Director of infrastructure l G. Page, Director of Ceramic Operations R. Sharkey, Director of Regulatory Affairs i J. Lang, Oxide Process Control Engineer l

LIST OF ACRONYMS USED HF Hydrofluoric Acid NMMA Nuclear Material Measurement and Accountability UF, Uranium Hexafluoride MC&A Material Control and Accounting KOH Potassium Hydroxide AIT Augmented Inspection Team ISA Integrated Safety Analysis BTP Branch Technical Position l UO, Uranium Oxide

> UO,F, Uranyl Fluoride CACO 2 Calcium Carbonate (Limestone)

CaF, Calcium Fluoride j CO 2 Carbon Dioxide l HO2 Water PPM Parts Per Million l

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