ML20056E870
| ML20056E870 | |
| Person / Time | |
|---|---|
| Site: | Framatome ANP Richland |
| Issue date: | 08/17/1993 |
| From: | Frain R SIEMENS POWER CORP. (FORMERLY SIEMENS NUCLEAR POWER |
| To: | NRC OFFICE OF ENFORCEMENT (OE), NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| EA-93-085, EA-93-85, IEB-91-001, IEB-91-1, NUDOCS 9308250251 | |
| Download: ML20056E870 (12) | |
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a SIEMENS August 17,1993 4
Director, Office of Enforcement U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Gentlemen:
Subject:
Reply to a Notice of Violation
References:
(1)
NRC Region V Letter to Siemens Power Corporation,
Subject:
Notice i f Violation and Proposed imposition of Civil Penalty of $12,500 (NRC Inspection Report Nos. 70-1257/93-02 and 70-1257/93-05), dated July 2,1993; EA 93-085 (2)
Siemens Power Corporation letter, R.G. Frain to Director, Office of Enforcement, U.S.
Nuclear Regulatory Commission, Payment of Civil Penalty, dated August 17,1993 l
Siemens Power Corporation - Nuclear Division (SPC) is responding to the Notice of Violation (Reference 1) which resulted from an incident that occurred on February 7,1993, involving the inadvertent discharge of approximately 124 kg of low-enriched uranium powder from a process system into a lexan enclosure. The occurrence of this incident was immediately reported by SPC to the NRC in accordance with the provisions of NRC Bulletin 91-01 and SPC internal procedures. The initial report by SPC indicated that affected processing systems were shut down because of the incident and would remain shut down pending an investigation by SPC. The initial report also identified that immediate inspection of the spill revealed the presence of tape on a limit switch intended to shut off the powder feeder in the event of feeder discharge tube separation, thus limiting the amount of powder spilled.
Cleanup of the spilled powder inside the hood was completed 30 minutes after SPC's initial report to the NRC Operations Center.
SPC management recognized that the seriousness of the incident was exacerbated by the fact that a limit switch had been disabled by the taping. We therefore directed extensive resources in selecting experienced operations, safety and engineering personnel to investigate this incident and its generic implications to insure all causal factors were identified and understood. Thorough corrective actions were developed and implemented to preclude recurrence of this type of incident and to correct the underlying causes.
E500:E R.G. Frain Siemens Power Corporation Nuclear Division - Engineering and Manufacturing Facihty Vice President 2101 Horn Rapids Road, PO Box 130. Richland. WA 99352-0130,,-
Manufactur;na Tel: (509) 375-8799 Fax: (509) 375-8402 8
]h 9308250251 930817 1
PDR ADOCK 07001257
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' August 17,1993 Page 2 An NRC Augmented Inspection Team (AIT) also conducted a special inspection during the period February 9-12,1993, in response to the incident.
Our specific responses to the violations of NRC requirements, as stated in the Notice of Violation, are provided as an attachment to this letter, along with a notarized statement of affirmation regarding the responses. In these responses, SPC accepts the violations and provides both underlying reasons and short-and long-term corrective actions for each violation.
We have also reviewed our ongoing Criticality Safety Analysis Update Program. A second criticality safety specialist has been hired and a third is in the process of being hired to insure technical support for the criticality safety program. This Criticality Safety Analysis Update Program is currently on schedule with our first major milestone (Phase l} having been completed on June 30,1993. Following the completion of Phase I, a prioritization of the system packages was conducted considering the results of the initial system reviews, system complexity, and operating history to select the first four systems for immediate attention. The powder preparation system was selected as the top priority under Phase 2 of the program.
Close attention by management is being provided through an assigned project manager and through frequent review of issues and progress by the program oversight committee established shortly after program development. We recognize that uncertainty exists within some estimated task durations and will provide quarterly progress reports for SPC management review and NRC information.
Under separate cover (Reference 2), SPC is submitting a check in the amount of $12,500 to address the civil penalty imposed by NRC in conjunction with the violations.
Siemens Power Corporation management and operating personnel are committed to the safe operation of its manufacturing facilities. The results of both the SPC and NRC investigations of this incident including the causes, corrective actions, and expected standards of performance have been communicated throughout the SPC Manufacturing organization.
Yours truly,
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R. G rain Vice President, Manufacturing Attachment cc:
B. Faulkenberry, Regional Administrator US NRC, Region V
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State of Washington County of Benton Robert G. Frain being first duly sworn,. deposes and says: I am the Vice President, Manufacturing for the Siemens Power Corporation - Nuclear Division. The attached Reply to.
a Notice of Violation (Siemens Power Corporation letter dated August 17,1993) was prepared under my supervision and direction, and, to the best of my knowledge and belief, the facts contained therein are true and correct.
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' Robert G in
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Dated I
Subscribed and sworn to before me this 17th day of August 1993 l
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ffU Nota Public
-f-7!/7!91 My Commission Expires:
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SIEMENS POWER CORPORATION (SPC) REPLY TO NOTICE OF VIOLATION DATED JULY 2, l
1993 (NRC INSPECTION REPORT NOS. 70-1257/93-02 AND 70-1257/93-05)
I Violation i Failure to comply with established operating procedures Example A Between September 11-14,1992, an ECN was not used for modification of the discharge tube of the feed hoppers on all four blenders by installing interlocks for the direct control of unanticipated discharges of fissile material.
SPC Response to Violation I. Example A SPC accepts this example of Violation I.
Reason for Violation 1. Example A The engineer in charge of the limit switch installation was knowledgeable of the Work Order (WO) and Engineering Change Notice (ECN) procedures and the criteria for choosing which option to use. The installation of the limit switches was a modification developed in response to one of nine problems found by SPC in August and September 1992 in a generic implications study to i
identify areas where additional controls were needed to prevent powder spills and enhance operators' ability to comply with batch size requirements. The study which precipitated these enhancements resulted from a non~ reportable powder spill.
Expediting the limit switch modification was judged to be important to reinforce the idea that a uranium powder spill is not an acceptable occurrence. The switches were not intended as an essential barrier to preclude accidental criticality.
SPC identified in its internal investigation that poor judgement by the responsible engineer was a causal factor in the powder spillincident because a WO was used for the installation of the limit l
switches instead of an ECN. SPC's WO and ECN procedures (EMF-858, procedure numbers 1.21 and 1.13, respectively) in effect at the time the switches were installed permitted engineering judgement, with concurrence from the engineer's manager and the Criticality Safety Specialist, for " minor changes". This provisic; was intended for minor modifications and enhancements where no changes to the operating procedures or to the functions of the equipment were anticipated.
In the judgement of the engineer, the limit switches were an enhancement to preclude the i
possibility of a powder spill within a moderator-controlled enclosure. He also judged that the limit switches would require no additional operator action for normal system operation. Since thic enhancement was recommended as a corrective action following an overbatching incident on August 27,1992, the engineer wrote " criticality safety" as the reason for the change on the WO form, thus ensuring high priority in scheduling. The WO and ECN procedures in effect at that time have been judged to be subject to misinterpretation, directly contributing to a decision by the engineer that, in hindsight, was incorrect.
Corrective Actions Taken SPC's intemalinvestigation of this event identified weaknesses in the WO and ECN procedures, as well as in the controls on the implementation of these procedures. To provide prompt l
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l assessment of the prevalence of this problem plantwide, an immediate review was made of all WOs outstanding at the time to determine if, in fact, any should be ECNs. Any discrepancies found were corrected prior to further work being performed on the particular project. In addition, I
the Manager, Manufacturing Engineering disallowed the use of WOs for all equipment modifications pending a review of the WO and ECN procedures.
Corrective Action to Avoid Further Violations The WO and ECN procedures were reviewed, revised, and then re-issued on March 1 and March 17,1993 respectively. The revisions accomplished an overall clarification of WO versus ECN requirements, thereby diminishing the likelihood of misinterpretation or misuse. in addition, the j
revisions categorically disallowed the use of work orders for any modifications to fissile material-i containing systems. All engineers within Manufacturing Engineering were trained on the revised procedures. Refresher training has been scheduled on an annual basis.
Date to be in Full Compliance All corrective actions to address this weakness have been completed.
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Violation I Failure to comply with established operating procedures Example B As of February 7,1993, interlocks on the discharge tube on the feed hoppers of the Une 2 and j
Line 3 blenders had been bypassed (taped to prevent operation) during the operation of the UO2
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powder preparation process.
SPC Response to Violation I. Example B SPC accepts this example of Violation I.
l Reason for Violation 1. Example B 1
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The SPC incident investigation team identified a number of underlying causes that were ccntributory to the taping of the limit switches. These causes were documented in the SPC j
Incident investigation Board (118) report and included:
1 Since a Work Order (WO) rather than an Engineering Change Notice (ECN) was i
used to install the switches, no formal method was available to notify Plant Operations that a modification to process equipment had been performed.
Shift turnover was less than adequate in informing followup shifts of the installation of the switches.
The existence of the powder feed interlocks and their opeiation were not identified in a procedure.
The design / installation of the interlock switch was less than adequate because
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frequent and spurious trips occurred.
Two other causes were identified as possibly having contributed Indirectly to the incident:
The " Maintenance Required" section of the powder preparation logs (filled out by
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powder preparation technicians) was being used to report process test results, thereby leaving no space available to report maintenance problems or, if so used, not making the item visible enough to be easily recognized.
The shift schedule worked by the conversion area shifts can cause communication to be difficult between the shifts and other support personnel.
The results of SPC's incident investigation indicate that the disabling of the interlock was not done as a deliberate act of misconduct to disable a safety interlock. The most likely intent of the operator, not knowing the full purpose and significance of the limit switch, was to prevent frequent spurious shutdowns of the feeder equipment.
Corrective Actions Taken The powder preparation systems were shut down pending a fullinvestigation and resolution of the February 7,1993, powder spill incident. Based on the results of the incident investigation and follow-on generic implications study, the following corrective actions relative to the switch taping were identified as being pre-startup requirements:
Plant Engineering provided maintenance and functional testing of all three powder preparation feed hopper limit switches.
Plant Engineering conducted an independent walk-through of the entire conversion area to assure the functionality of all limit switches and interlocks.
Plant Operations revised applicable SOPS to include all pertinent interlocks, starting in the powder preparation areas and extending throughout Plant Operations. The SOP revisions re-emphasized the prohibition against bypassing interlocks unless authorized by procedure.
Plant Operations re-trained production personnel on updated SOPS.
incident briefings were conducted by Plant Operations management with all a
production personnel. In addition to giving a fuli description of the incident, the briefings stressed that SPC has a license obligation to follow procedures and that the bypassing of interlocks is unacceptable unless for a defined purpose, e.g.
calibration, and in accordance with an approved written procedure.
Corrective Action to Avoid Further Violations l
The following corrective actions in the general areas of equipment readiness, procedural l
compliance, and communication were identified to avoid future incidents of this sort:
l Plant Engineering formed an independent task force to review the operation and
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condition of other interlock / limit switches plant-wide.
Plant Engineering provided a review of alternate designs for the powder feed discharge tube system for possible improvements or simplification.
The Plant Manager icsued a memorandum to all Manufacturing personnel re-emphasizing the importance and requirement for not disabling any interlocks or safety devices except for a defined purpose, e.g. calibration, and in accordance with an approved written procedure.
The plant " Master Safety Rules" were revised to specifically prohibit the disabling of interlocks without an approved written procedure.
Chemical Operations instituted "re-entry" meetings after shift long changes, including reviews of operations supervisor's icgbooks, notebooks with ECNs and WOs, Abnormal Event Reports, and SOP changes.
The format of the powder preparation log was changed to provide a section for process test results, thereby leaving the " Maintenance Required" section available for that purpose.
Plant Operations implemented a new form by which. chemical operators can request equipment or process modifications.
The shift implementation was re-evaluated with an employee-participatory task force in an effort to improve communications.
Plant Operations accelerated preparation and issuance of Operator Qualification Training Manuals, a training enhancement initiated before the February _7,1993, l
Prior to the February 7,1993, spill, Plant Operations had commissioned performance-based audits by Quality Assurance, Plant Operations supervisors, and senior operators for procedure compliance.
After the spill, Process Engineering was also enlisted to assist in performing these intemal audits.
Plant Operations will conduct self-assessment reviews versus " conduct of l
operations" requirements in areas such as communications, shift turnover, and operating procedures.
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i Date to be in Full Compliance Completion of pre-startup requirements was confirmed by a formal SPC Startup Council, which authorized re-start of the powder preparation systems as of February 11,1993. Based on this
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determination, SPC considers that these systems are being operated in full compliance. All corrective actions aimed at avoiding further violations have also been addressed, the most recent l
of which is the Plant Operations self-assessment initiative. The first self-assessment action in this regard was conducted over the week of August 9,1993.
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Violation 11 Weaknesses in Criticality Safety Analyses (CSAs)
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Example A Between September 11-14,1992, equipment was added to a manufacturing process but a new CSA was not performed to evaluate the addition. Specifically, interlocks used as controls to prevent discharges of low enriched UO from the confines of the process system were added 2
to the discharge tube of the feed hoppers on four blenders in September 1992, and the new controls were not described in a CSA.
SPC Response to Violation 11. Example A SPC accepts this example of Violation 11.
Reascn for Violation 11. Example A The interlock switches were installed to prevent the inadvertent discharge of significant quantities of UO Po.vder from the confines of the powder preparation system into the feed hopper hood.
2 Since the switch installation was precipitated by a generic implications study of an earlier non-reportable powder spill and was being conducted under a Criticality Safety Corrective Action Request (CSCAR), the Criticality Safety Specialist (CSS) was involved from the outset. The CSS evaluated the modification and although it was viewed as an enhancement to criticality safety, the switches were not viewed as required controls to assure criticality safety since the double contingency principle had already been satisfied and no new accident scenarios resulted from their installation. Based on this evaluation by the CSS, no action was taken to produce a new or amended CSA.
Corrective Actions Taken The powder preparation systems were shut down pending a full investigation and resolution of the February 7,1993 powder spill incident. SPC gave further consideration to the status of the powder feeder limit switches and determined that the level of criticality safety would be enhanced by designating these devices as being part of the criticality safety controls. This decision considered not only the assurance of double contingency but also the advantages with respect to enhanced worker awareness of criticality safety controls. Accordingly, the powder feeder limit switches have been incorporated into the applicable CSA and a routine testing / maintenance schedule has been established by including the switches in the Instrument Repetitive Maintenance (IRM) system.
Corrective Action to Avoid Further Violations As presented to NRC in writing on December 30,1992, and via a presentation and progress report at the Mey 17, 1993 enforcement conference in NRC Region V offices, SPC has undertaken a comprehensive update of its criticality safety analyses. This update program includes a thorough review of all CSAs, to include whether necessary controls are present and properly documented. This program will significantly enhance the completeness, consisten::y and documentation of SPC's CSAs.
Evaluation and resolution of th;s incident has also pointed to a need to clarify certain portions of Chapter 3 of the SPC Safety Manual (EMF-30) which may be subject to misinterpretation. In a
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9 particular, EMF-30, Chapter 3.0, Appendix 2, " Guidelines for Requesting CSA for Plant Design Changes and the Addition of New Equipment," and EMF-30, Chapter 3.0, Section 4,1 need to be made consistent in clearly stating SPC's policy that changes or additions to fissile material-containing equipment must be appropriately evaluated, i.e. analyzed, for criticality safety impact but that a new or amended CSA may or may not be required.
Date to be in Full Compliance All changes have been completed to incorporate the limit switches into the applicable CSA and to assure periodic inspection / maintenance of the switches as criticality control devices. The comprehensive CSA update program is ongoing and is currently on-track with the program schedule provided to NRC. Completion of this estimated two-year program is currently projected for January 1995.
Revisions to the SPC Safety Manual to clarify sections addressing requirements for new or modified CSAs will be completed by September 30,1993.
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Violation 11 Weaknesses in Criticality Safety Analyses (CSAs)
Example B As of February 12,1993, the licensee had not determined that the conversion Line 2 unfavorable geometry UO powder preparation systems (PPSs) would be subcritical under both normal and 2
credible abnormal conditions and had not carefully evaluated the potential of accidental moderation due to water leaks, sprays, overflows, and siphoning. Specifically, the licensee did not maintain an evaluation with the technical basis to demonstrate that liquid moderating systems within the same room and near conversion Line 2 PPSs did not pose a criticality concern. As i
a consequence, the controls necessary to preclude the intrusion of moderating liquids into the PPSs from breaks in nearby moderating liquid lines were not clearly specified, SPC Response to Violation 11. Example B SPC accepts this example of Violation 11.
Reason for Violation 11. Example B Criticality safety and, in particular, moderation control in the powder preparation systems have been addressed in CSAs covering the specific components of the system e.g. slab hoppers, blenders, hammermills, etc. Support equipment such as hoods and vacuum transfer systems were specifically reviewed for criticality safety as part of their installation under the Engineering Change Notice (ECN) system. The presence of liquid moderating systems (e.g. water lines, steam lines) and their attendant criticality safety implications were not documented as specific evaluations; instead the presence of such systems is controlled via a general Criticality Safety Specification addressing moderation control areas (Criticality Safety Specification EMF-P67,252).
In the case of the Line 2/3 powder preparation systems, the position of SPC's safety staff was that the intrusion of moderators into the powder preparation vacuum transfer system and the subsequent transport of moderators into unsafe geometry, moderation - controlled equipment during accident conditions was not credible when reasonable operator action was considered.
Furthermore, the placement of the equipment in hoods was viewed as an effective barrier to moderator intrusion via sprays.
Compliance with the Criticality Safety Specification for moderation control areas was judged to be adequate and no additional documentation of moderator intrusion scenarios was deemed necessary.
Corrective Actions Taken The powder preparation systems were shut down pending a full investigation and resolution of l
the February 7,1993, powder spill incident. Pursuant to a NRC Region V Confirmatory Action l
Letter, SPC performed an engineering evaluation of the potentialintrusion of moderating liquids l
into the uranium oxide blending and powder preparation system to define the specific controls necessary to prevent criticality.
This moderator intrusion study, conducted by a team representing Manufacturing Engineering and Plant Operations, involved a systematic evaluation of specific accident scenarios related to moderator intrusion into the powder preparation area.
The study then documented existing controls already in place to protect the system from moderator intrusion via the identified paths. The information deve!oped during the evaluation was utilized to assess whether existing controls were sufficient to preclude loss of moderation control via moderator intrusion into the system.
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- 9 The evaluation concluded that adequate controls to prevent criticality were in place under normal operating conditions.
Criticality safety u,nder certain accident conditions is assured by
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reasonable and straightforward operator response. The evaluation did identify a number of i
improvements that will enhance the level of control under postulated accident conditions, thereby l
providing a greater degree of protection. Five of the enhancements were scheduled for near term action and have all been completed. Two additional modifications identified in the analysis l
required more substantial engineering analysis / design work. One of these modifications will be l
completed in August,1993, the second in November 1993.
Corrective Action to Avoid Further Violations As discussed under Violation 11, Example A, SPC has undertaken a comprehensive update of its CSAs. The update program includes the consolidation of SPC's significant number of existing -
CSAs into approximately fifty system-based CSAs. The updated CSAs will be enhanced with respect to completeness, consistency, and supporting documentation. In addition, the systems approach will enable SPC to more effectively analyze and document the criticality safety implications brought about by the interactions between individual pieces of process equipment as well as between process equipment and supporting systems such as ventilation systems, l
product transfer systems, water and steam systems, etc. As a result, CSAs will be more comprehensive and documentation of CSAs will be more complete.
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The moderator intrusion study has been completed and was transmitted to NRC on April 22, 1993. All near-term enhancements identified in the study have been completed; two remaining l
long-term enhancements are scheduled for completion in August and November,1993. The comprehensive CSA update program is ongoing and is currently on-track with the program schedule provided to NRC. Completion of this estimated two year program is currently projected for January 1995.
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