ML20128N722
| ML20128N722 | |
| Person / Time | |
|---|---|
| Site: | Portsmouth Gaseous Diffusion Plant |
| Issue date: | 10/10/1996 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20128N721 | List: |
| References | |
| 70-7002-96-05, 70-7002-96-5, NUDOCS 9610170025 | |
| Download: ML20128N722 (11) | |
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U. S. NUCLEAR REGULATORY COMMISSION REGION III Docket No.
70-7002 Certificate No.
N/A Observation Report No.
70-7002/96005 (DNHS)
Applicant:
United States Enrichment Corporation Facility Name:
Portsmouth Gaseous Diffusion Plant Location:
3930 U. S. Route 23 South P. O. Box 628 Piketon, OH 45661 Dates:
July 30, 1996 through September 4, 1996 Inspectors:
C. R. Cox, Senior Resident Inspector D. J. Hartland, Resident Inspector Approved By:
Gary L. Shear, Chief Fuel Cycle Branch l
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9610170025 961010 PDR ADOCK 07007002 C
PDR 1
EXECUTIVE
SUMMARY
United States Enrichment Corporation Portsmouth Gaseous Diffusion Plant NRC Inspection Report 70-7002/96005(DNMS)
This observation report includes aspects of plant operations, maintenance / material condition, engineering, and plant support. Observations were made by the resident inspectors as part of their routine duties.
Authority Statemqnti The Department of Energy (D0E) and the Nuclear Regulatory Commission (NRC) have agreed to cooperate to facilitate the NRC's obtaining of information and knowledge regarding the gaseous diffusion plants and the United States Enrichment Corporation's (USEC) operation thereof through observation / inspection activities during the interim period before the NRC assumes regulatory responsibility. This report is a summary of NRC observations for the period stated.
Each of the observations was communicated to the DOE site safety staff and USEC site staff during and at the end of the observation period to allow for their future followup and evaluation, as appropriate.
l Plant Ooerations The inspectors identified numerous problems in the conduct of operations regarding the Operational Safety Requirements (OSR) violation from the treatment of a cell with freon left in the gas cooler. The event also identified problems in modification control (Section 01.2).
Continued poor material condition resulted in nuclear criticality concerns in the cascade buildings (Section 01.3).
Maintenance and Surveillance A failure to follow work controls led to an electrician receiving minor burns due to an electrical arc (Section M1.2).
Enaineerina Poor equipment history contributed to a delay in detecting a design problem with a power rail for the X-344 building crane (Section E2.2)
Limited management awareness of procedural requirements and 'a continued weakness in the Unreviewed Safety Question Determination program was identified by a procedure violation in moving cylinders at the Low Assay Withdrawal cooldown pad (Section E2.2).
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REPORT DETAILS Summary of Plant Status The plant operated at approximately 1400 MW during most of this observation period.
I.
Doerations 01 Conduct of Operations' 01.1 General Comments The inspectors observed selected operational activities.
Specific events and noteworthy observations are detailed in the sections below.
01.2 Operational Safety Reauirement Violation: Treatina Cell Without Drainina Freon a.
Inspection Scope The inspectors reviewed the circumstances surrounding treating a cell in the X-333 building without having drained the freon from the gas cooler in violation of Operational Safety Requirements (OSRs).
b.
Observations and Findinos On July 31, 1996 the operators in the X-333 building drained freon from the gas coolers in the odd stages of Cell 33-8-10.
Normal operations would involve draining both odd and even stages of the cell.
However, after draining the odd stages, operators noted that the even stages could not be drained because the freon drain tank was full.
The operators completed the evolution on the odd stages by drawing a vacuum on the freon side and shutting and h
locking the odd side drain valves. No log entry was made to indicate that the even side was not drained nor was the status made a shift turnover item.
The odd side was then treated with Chlorine Trifluoride (ClF3) to remove deposits. During the treatment period, daily freon levels were recorded on logs sheets indicating the amount of freon in the gas cooler system in inches.
The readings on the even side varied from approximately 129 inches to empty over the time period with one entry indicating three different levels for the same indication with a question mark by each recorded level.
Each log
' Topical headings such as 01, H8, etc., are used in accordance with the NRC standardized inspection report outline contained in NRC Manual Chapter 0610.
Individual reports are not expected to address all outline topics, and the topical headings are.therefore not always sequential.
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sheet was signed by a Front Line Manager (FLM).
From August 25, 1996 through August 27, 1996, the even stages were treated without the freon being drained from their gas coolers. OSR Section 2.4.1 required cells being treated with CIF3 to have the gas coolers drained of freon. Draining the freon was a precaution to prevent explosive mixtures of freon and ClF3 from forming in the cells due to a possible gas cooler leak. Other precautions, which were followed, were the monitoring of the cell temperatures during cell treatment and the use of an infrared analyzer to measure the ClF3 and freon levels in the cell, also during treatment.
When opening a valve for refilling the gas cooler with freon on August 27, 1996, the operators noted that the supposedly empty gas cooler had freon pressure.
Further investigation by the facility revealed the even side had not been drained and the resultant OSR violation.
The inspectors reviewed the logs from the event and walked down the freon level indicators in the facility with the Cascade Operations Manager. The inspectors and manager noted the inconsistent log entries for the freon level.
From the walk down of the level indicators, the inspectors and manager identified a problem with the newly installed magnetic level indicators (MLIs).
The indicators had magnetic floats riding on the freon level changing the indicators from white to red. The freon level was supposed to be indicated by a solid red line with a solid white line above the level. On some of the indicators in the field, the level indication was in onsistent with the red line sometimes broken up with several white indications and vice versa. When the operators were interviewed, several had called this type of indication a " barber pole" indication. The level indicator for the even side of the treated cell was one of the " barber pole" indicators.
The Cascade Operations Manager had the system engineer investigate the problem with the MLIs. The system engineer concluded that the problem started with the initial installation. When the level indicators were shipped and installed, the magnetic float was allowed to roll up and down the tube. That movement would cause the red and white indicators to align according to the magnetic float's polarity giving false indications. As the indicators were filled with liquid, the float would align properly at the bottom of the tube and correct the indicators as it passed each level.
This process was called "self correcting". However, the magnetic float could not "self correct" indications above the highest liquid level. Therefore, some of the false indications caused by shipping and installation were not immediately corrected. When the operators first started to read the new MLIs, they found these false indications. They determined that they could correct the false indications with a magnet attached to the end of a stick.
However, use of the stick was not controlled and if not carefully used, the stick, itself, could cause false level indications.
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This level indication problem was never noted in the plant problem reporting system.
c.
Conclusions This event highlighted several fundamental problems in the routine conduct of operations.
Log entries and turnovers were inadequate in identifying current plant status.
Lockout tagouts (LOTO) were not consistently used for similar events. Operators interviewed indicated that since the odd side was tagged out indicating the freon was drained, they assumed that the even side was drained since that was normal operations and they did not always tagout the systems when drained.
FLM and operators failed to demonstrate a questioning attitude. The conflicting log entries for the freon level should have raised a question about the actual status of the even side. One FLM signed a log sheet with three different readings on the same space where the operator placed question marks by each reading. When the operator was interviewed, he stated that he could not tell what the level was so he put all three levels down. Operators were not using the problem reporting system to identify the MLI problems and developed a work around to try to correct what they thought were erroneous readings.
The event also raised questions about the modification control program.
There was no apparent startup testing after installation of the new MLIs wh -h would have identified the false indications that arose from transportation and installation. An adequate testing program would have corrected the false readings which led to the operator work around with the magnet on the stick. The system engineer provided some training to the operators on the MLI modification during the initial installation. However, there was nothing incorporated in the training program for new operators nor the reassigned operators.
01.3 Poor Material Condition leadina to Assay limitation problems in the X-333 Buildina a.
Inspection Scope The inspectors performed regular reviews of the Cascade Contro11ers' logs, discussed plant status with the on-shift Cascade Controller, and walked down the Plant Control Facility mimic panels.
b.
Observations and Findinas On August 14, 1996, the inspectors noted that there was unusually high UF, sampling activities in the X-333 building beginning on August 13, 1996. Discussions with the Cascade Coordinator I
indicated that the U, assay levels in the X-333 building had u
reached an administrative alert level. That alert level had recently.been established due to the cascade gradient causing 5
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higher enrichment levels lower down in the cascade.
Those higher enrichment levels raised concerns that OSR limits could be 1
challenged. Therefore, alert levels were established so that increased sampling could be initiated to ensure compliance with the OSR limits. The samples indicated that no OSR limits were exceeded.
The cascade gradient is determined by the flow rates and pressures of the UF. in the cascade. The flow rates and pressures are primarily dictated by the number of available cells, the available l
electricity, and the amount of UF, available to feed. Due to poor material conditions in the cascade buildings, a large number of cells were unavailable during this time period. The lack of cells required the cascade gradient to be more compressed than usual.
The compression of the gradient was the reason why assay levels were high in the X-333 building.
c.
Conclusions Poor material condition in the X-333 building continued to challenge criticality safety limits in the 0SRs.
Establishment of i
the alert level and preplanning an increased sampling plan if the level was reached were appropriate for the unusual cascade configuration.
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Maintenance i
M1, Conduct of Maintenance and Surveillance M1.1 General Comments During routine tours of plant facilities, the inspectors observed the general physical condition of plant equipment and some in-progress maintenance activities. The inspectors also reviewed some maintenance records and maintenance-related nonconformance reports. The focus of the observations was to assess the overall performance of maintenance activities and their. effectiveness in maintaining the material condition of the plant's facilities, systems, and equipment.
M1.2 Electrician Received Electrical' Burns Due to Violatina Work Control Procedures a.
Inspection Scope The inspectors reviewed the circumstances associated with an electrician receiving burns from an electrical arc.
b.
Observations and Findinas On August 6, 1996, an electrician working in the X-330 building received minor burns while working on a 480 Volt breaker..The electrician had been working under an approved work package to 6
reset another breaker for a unit supply fan. When the supply fan breaker failed to reset, the electrician by-passed normal work control practices and decided to switch the bad breaker with an unused breaker installed in another local control center. The electrician began removing the unused breaker without electrically isolating the breaker. Apparently, a screwdriver he was using to remove a screw on the B phase connector came in contact with a metal plate and an electric arc resulted. The arc burned the electrician's face, neck, and right hand and he required medical attention.
He did not receive an electrical shock.
The electrician admitted during the event investigation that he violated the required work control practices and that he was aware of the requirements.
c.
Conclusions The intentional violation of work control practices, a fundamental administrative control used to ensure worker safety, resulted in minor burns. However, electrocution easily could have been the final result.
III.
Enaineerina El.
Conduct of Enaineerina Throughout the observation period, the inspectors observed facility engineering activities, particularly the engineering organization performance of routine and reactive site activities, including identification and resolution of technical issues and problems.
E2 Enaineerina Support of Facilities and Eauioment E2.1 Inadeauate Desian for Crane Power Rail a.
Scope The inspectors reviewed the circumstances surrounding a repeated loss of power to a crane in the X-344 building.
b.
Observations and Findinas l
On August 12, 1996, a crane in the X-344 building lost power which left a 21/2 ton cylinder filled with solidified UF. suspended approximately 2 feet above the building floor. Troubleshooting efforts identified that the power rail supplying electricity to the crane had separated at its expansion joint. The separation resulted in the crane losing one of the three electrical phases supplied by the rail. The loss of one phase was enough to cause the crane to stop all movement.
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w The crane had previously lost power in 1995 and March 1996. The power loss in 1995 left a liquid filled 21/2 ton cylinder suspended while the March 1996 event did not involve a suspended cylinder. The system engineer investigated the March 1996 event and determined that another expansion joint was needed to accommodate the thermal expansion and contraction of the rail.
She initiated a modification package to install the extra expansion joint that was reviewed and approved.
Because of this effort, the modification package and the required parts were available and quickly installed, restoring power to the crane.
During interviews with the inspectors, the crane system engineer acknowledged that she was not aware of the loss of power event in 1995. The position had only been created late in 1995 and the plant equipment history did not ideatify the earlier 1995 event.
The inspectors noted that since the position had been created a liquid cylinder handling sub-committee was established with the engineer providing a key role. The sub-committee reviewed the condition of the liquid cylinder cranes and identified many material condition problems. Many of the crane problems were due to the age of the cranes and previous inadequate maintenance and surveillance. The system engineer had established a status log for every crane which included the action plans to remedy the identified crane problems with short term and long term actions.
c.
Conclusions The problem with the expansion joint appeared to be a design problem that the system engineer remedied. Had the engineer been aware of the earlier event, the design problem would have been identified and remedied earlier.
Poor equipment history has been a problem identified by the facility and better record keeping for maintenance activities has been initiated.
E2.2 Unreviewed Safety Ouestion durina Movement of Emoty UF6 Cylinders at Low Assay Withdrawal (LAW) Cooldown Pad a.
Inspection Scope The inspectors reviewed an event that involved moving three empty 10 ton UF, cylinders at the LAW cooldown pad onto scale carts using cylinder stackers, b.
Observations and Finding 1 On August 15, 1996, facility staff moved three empty 10 ton cylinders from the LAW cooldown pad onto scale carts outside the LAW station. Normally the cylinders were moved by the LAW cratie but the crane was out of service.
Instead, a small cylinder stacker was used. The cylinder stacker was a small mobile piece of equipment used to move cylinders primarily in cylinder yards.
The Assistant Operations Manager, Plant Shift Suprintendent, 8
Shift Engineer, and a Nuclear Safety Analysis Engineer were all involved in approving the use of the cylinder stacker.
They determined that the only restriction in moving cylinders was the movement of liquid filled cylinders by mobile equipment. The Shift Engineer identified a concern that there were liquid filled cylinders on the cooldown pad.
Therefore spotters were used to ensure that the cylinder stacker would not run into a cooling cylinder and risk a large release. The evolution was carried out with no noted problems.
While reviewing the LAW crane outage, the inspectors and DOE Site Safety Representatives (SSRs) questioned the movement of the empty cylinders. The SSRs further investigated the movement and identified a procedure violation.
Procedure XP4-CO-CA2367 required the use of the crane to place empty cylinders onto the scale carts. Once the procedure violation was pointed out to the facility, a problem report was issued and the Shift Engineer made a Unreviewed Safety Question Detarmination (USQD). The Shift Engineer determined the event was not a Unreviewed Safety Question (USQ). The NRC inspectors highlighted that mobile equipment use around cooling cylinders could contribute to a large release of U F.. A probability risk assessment at the facility identified mobile equipment accidents as a 25 per cent contributor to large release scenarios.
It was also evident to the inspectors that the normal control of cylinder movement at the LAW cooldown pad was designed to minimize use of mobile equipment around cooling cylinders. Normally, empty cylinders would be dropped off at the west end of the pad away from any cooling cylinder. Then the crane would be used to move the empty cylinders across to the east end of the pad to the scale carts.
c.
Conclusions While the cylinder movements were conducted safely, the inspectors concluded that the movement of the empty cylinders was a USQ. The definition of a USQ in 10 Code of Federal Regulations Part 76 states that a possibility of an accident or malfunction of a different type than any evaluated in the safety analysis report (SAR) may be created would constitute a USQ. An accident involving a cooling cylinder with mobile equipment could cause a 1
large release. That accident scenario was not evaluated in the SAR but was considered bounded by the dropping of a full liquid cylinder scenario. Therefore, the USQD completed by the Shift Engineer was incorrect and was a further indication of previously noted weaknesses in the safety analysis program. The evolution also identified a concern that the decision to conduct the i
evolution was made without knowledge of the procedure, especially with the relative senior level of management that was involved in the decision.
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Manaaement Meetinas X1 Exit Meetina Summary The inspectors met with facility management representatives and the DOE Site Safety Representatives throughout the observation period and on i
September 4, 1996.
The likely informational content of the observation report was discussed. No classified or proprietary information was identified.
No disagreement with observations or findings, as described by the inspectors at these meetings, was identified.
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Partial List of Persons Contacted Lockheed Martin Utility Services (LMUS)
- D. I. Allen, General Manager J. E. Shoemaker, Enrichment Plant Manager
- J. V. Anzelmo, Work Control Manager
- R. W. Gaston, Nuclear Regulatory Affairs Manager
- C, F. Harley, Engineering Manager
- G. S. Price, Maintenance Manager
- C. W. Sheward, Operations Manager United States Enrichment Corooration
- J. H. Miller, USEC Vice President, Production
- L. Fink, Safety, Safeguards & Quality Manager United States Department of Enerav (D0E)
J. A. Crum, Site Safety Representative
- J. C. Orrison, Site Safety Representative Nuclear Reaulatory Commission (NRC)
C. R. Cox, Senior Resident Inspector F. D. Brown, Resident Inspector C. B. Sawyer, Project Manager
- Denotes those present at routine resident exit meeting held on September 4, 1996.
ITEMS OPENED. CLOSED. AND DISCUSSED Opened None Closed None Discussed None Certification Issues - Closed None 11