IR 05000317/1994031
| ML20149H389 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 11/14/1994 |
| From: | Ruland W, Scholl L NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20149H382 | List: |
| References | |
| 50-317-94-31, 50-318-94-30, NUDOCS 9411220159 | |
| Download: ML20149H389 (10) | |
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U. S. NUCLEAR REGULATORY COMMISSION
REGION I
DOCKET / REPORT N0S:
50-317/94-31 50-318/94-30 j
LICENSEE:
Baltimore Gas and Electric Company (BG&E)
FACILITY:
Calvert Cliffs, Units 1 and 2 Lusby, Maryland DATES:
October 3-7, 1994 Ndh[
r22 FOR H Nov 91 INSPECTOR:
Larry L. Scholl, Reactor Engineer Date Electrical Section Division of Reactor Safety
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APPROVED BY:
Milliam H. Ruland, Chief
' Bat'e Electrical Section Division of Reactor Safety Areas Inspected: An announced safety inspection was conducted to assess the engineering organization's effectiveness in making design changes and in resolving technical issues to assure safe plant operation.
Specifically, the
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inspector reviewed permanent plant changes, temporary alterations, resolution
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of recent technical issues and engineering department initiatives.
Results: The inspector determined that the engineering departments were providing good engineering and technical support for the operation of the plant.
Plant modifications and safety evaluations reviewed were generally of
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good quality. The engineering work backlog is closely monitored and efforts to reduce the backlog have been effective. The resolution of emergent technical issues was timely and effective. Management support of initiatives to improve the engineering processes and products was evident in several areas.
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DETAILS I.0 BACKGROUND (NRC IM 37550)
The purpose of this inspection was to evaluate the effectiveness of the licensee's engineering organization to perform routine and reactive site activities. The structure of the engineering department and the division of responsibilities between the engineering departments was reviewed. Other activities reviewed included permanent and temporary plant modifications and the identification and resolution of emergent technical issues and problems.
2.0 ENGINEERING ORGANIZATION AND RESPONSIBILITIES Engineering support for the operation of Calvert Cliffs Units 1 and 2 is provided by the nuclear engineering and plant engineering departments. The primary purpose of the nuclear engineering department is to provide design engineering and nuclear fuel management support and to identify and resolve long-range engineering issues.
Specific functions of the nuclear engineering department include:
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serve as the Calvert Cliffs Design Authority;
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perform multi-disciplinary design ard analysis support;
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perform design engineering for permanent and temporary plant modifications including all associated safety evaluations;
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manage the nuclear fuel cycle, and;
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design bases documentation.
A separate unit, the plant design support unit, functions to provide multi-discipline engineering support for non-scheduled design needs that require a quick response.
The plant engineering department provides support of all activities associated with the plant systems and equipment. This support is provided primarily through the assigned system engineers who assume ownership of their assigned systems and as such are the primary point of contact for operations,
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maintenance and design issues that affect their systems.
Specific system
engineer responsibilities include:
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periodic system walkdown inspections to identify deficiencies and recommend corrective actions;
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track open work on assigned system and assess impact of open items and provide input to operations department;
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lead investigations and troubleshooting efforts for system problems;
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provide technical support for the maintenance department;
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assist operations in determining system operability and provide justifications for continued operation when necessary;
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perform root cause analysis for component and/or system failures and provide recommended corrective actions, and;
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provide technical support for assigned classes of components.
Within the plant engineering department the plant testing group has been formed in an effort to improve the control and quality of all plant testing
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activities.
In addition to the engineering support provided by the engineering groups during the normal working hours, a system engineer and two design engineers are assigned to provide on-site support to operations and maintenance during the nightshift. The design engineer complement is comprised of a mechanical or civil engineer and an electrical or instrumentation and controls engineer to provide a multi-discipline support capability. The assignments are changed each week.
The use of the issue report system for documenting problems, the involvement of engineering in daily meetings with maintenance and operations department personnel and the back shift engineering support by both engineering departments results in good communications between the site departments and between engineering groups.
Conclusion Through reviews of engineering activities and discussions with personnel within the various engineering groups, the inspector found that there was a clear division of responsibilities between the groups.
The system engineer was clearly recognized by all groups as the primary contact for engineering support to the assigned systems. Communications between engineering and other plant departments is good.
3.0 ENGINEERING WORK BACKLOG / PERFORMANCE MONITORING The inspector reviewed the engineering work backlog and associated performance monitoring data to assess the effectiveness of BG&E's efforts to manage the work backlog. The inspector found that the engineering departments utilize numerous performance indicators to permit an internal performance assessment and to determine how well they are supporting the overall station goals. A review of a sample of the performance statistics as of September 1994 indicated that:
the number of major plant modifications to be completed has decreased by
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more than 20% between December 1993 and September 1994 and a gradually declining trend was indicated; the number of minor plant modifications to be completed has also
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decreased significantly since December 1993 and continues to decline;
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the number of maintenance orders that were delayed pending engineering assistance has fluctuated and currently was higher that the station goal;
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l the number of temporary modifications that have been installed for
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greater than 90 days is below the established goal and there was no significant increasing or decreasing trend indicated.
l Conclusion The inspector concluded that overall the engineering backlog has been decreasing and is receiving appropriate management attention. The inspector-also noted that engineering and maintenance managers were currently visiting another power plant site in an effort to gain additional insights on how to improve the engineering support to maintenance activities.
4.0 PLANT MODIFICATIONS Facility Chanae Reauest (FCR)93-207 - Installation of Containment Air Cooler
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Inlet Valves
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The purpose of this modification was to install new service water control valves at the inlet to the containment air coolers (CACs). BG&E determined that under certain accident conditions the amount of heat transferred from the
containment to the service water system (via the CACs) could result in an excessive temperature rise in the service water system. This service water system temperature increase could jeopardize the operability cf the emergency
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diesel generators (EDGs), since they are als, cooled by the service water system. To control the heat input to the service water system BG&E decided to replace the service water inlet valves to the CACs with valves that would be automatically throttled immediately after an accident. These valves would automatically return to the full open position when the heat load on the CACs had decreased. The original valves were designed to be either fully open or
fully closed and did not have a throttling capability. This control
arrangement would ensure that the EDG cooling remains adequate throughout the accident sequence.
The modification consisted of the replacement of the 8" control valves,
modifying the control circuitry and connection of the valve control air supply from the non-safety grade instrument air system to the safety grade salt water
air system.
The inspector discussed the modification with the design engineers, reviewed the modification documentation and performed a field inspection of the
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i installation for one of the affected trains. The inspector found that a very
thorough and detailed safety evaluation was performed and that the safety i
evaluation had been properly reviewed and approved by the plant operations and
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safety review committee (PORSC). The inspector also verified that the licensed operators had received training on the modification and that the affected critical drawings and operating procedures had been updated to reflect the changes to the service water and instrument air systems. The post-modification testing was also reviewed and found to be thorough and appropriate acceptance criteria was specified. The inspector reviewed the periodic testing to be performed as part of the routine surveillance test program and found it to be appropriate with one exception.
The inspector noted that surveillance tests STP-0-4A(B)-1(2), "A(B) Train Integrated
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Engineering Safety Features Test," specified a minimum flow to each CAC of 1400 gpm. This flow rate is the value assumed in the accident analyses and does not allow for uncertainties such as instrument error. The use of this criteria was discussed with the engineers who stated that the purpose of this test was not to verify the flow rate but to verify the system control logic.
However, an action item was initiated by BG&E to review and revise the flow rate criteria in the tests, that are performed once per refueling interval, to
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establish an acceptance criteria that would permit the identification of l
degraded flow conditions during this test. There was no immediate concern as to the adequacy of the flow rates since the post modification test contained appropriate acceptance criteria.
Minor Modification 94-024-005-00 - EDG Exhaust Pioina Support Modification
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During work on the new emergency diesel generator building in June 1994, questions were identified by engineering as to the adequacy of the design for the exhaust piping for the existing EDGs. The question was whether the exhaust piping and supports were adequate to withstand the forces developed by a tornado. At that time, BG&E performed an engineering evaluation and determined that the supports for the piping were adequate to maintain the EDGs operable fellowing a tornado. However, it was determined that the original design did not fully meet the ASME code requirements. A modification was then initiated to upgrade the supports on the EDG exhaust piping to ensure the pipe stresses from a tornado would be within those allowed by the ASME code.
(See Inspection Report 94-020 for additional information).
The modification design instructions and construction notes specified the sequence in which the work on the supports was to be performed so that the exhaust piping would remain functional for all design conditions during the modifications. To rework the final support at the end of the exhaust piping installation, it was required to remove a snubber that provided an anchor point from the pipe to the auxiliary building wall.
During the work on the exhaust piping supports for the 21 EDG, the shift supervisor questioned whether entry into the technical specification limiting condition for operation (LC0) for inoperable snubbers was required to perform the pipe support work. Technical specification (TS) 3.7.8.1, " Snubbers,"
requires, in part, that all safety related snubbers shall be operable in operating modes 1,2,3, and 4.
The TS action requires that inoperable snubbers be replaced or repaired and an engineering evaluation be performed within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. The bases of this TS states that operation with an inoperable snubber may continue indefinitely if the system to which the snubber is attached can
continue to perform its function with the snubber inoperable.
The inspector reviewed the modification with the design engineers and the associated modification documentation to determine if the effects of the snubber removal during the construction sequence had been properly assessed.
A field inspection of the exhaust piping and associated supports was also performed. The inspector found that the safety evaluation screening had been performed and the results of the screening by the design engineer concluded that a safety evaluation was not required. The bases for this decision was that the upgrade of the supports provided additional design margin with
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respect to the effects of a tornado on the exhaust piping and in no way impacted the ability of the EDG to perform its safety function.
The design instructions and construction notes provided in the modification documentation stated that, "The piping will remain functional during and after a seismic
I event with the snubber removed during construction." The inspector questioned whether an analysis or calculation had been performed to support this conclusion. The engineers stated that the bases for this statement was that, in their engineering judgement, the forces of a tornado would be significantly higher than those during a design base seismic event and therefore the calculations supporting upgrading the supports for a tornado bounded the effects of a seismic event. They also noted that the original operability determination calculations, performed in June 1994 to assess the effects of a tornado, assumed the snubber anchor point would fail during a tornado and was not considered functional during that analyses.
Following the questions by the operations department regarding the technical specifications, design engineering performed a calculation to assess the effects of a seismic event on the piping with the snubber removed.
The inspector reviewed the results of this calculation and compared them to the results obtained for the calculation for design bases tornado effects. The
results indicated that the tornado-induced stresses were significantly higher than the stresses imparted during a seismic event. Also, the analyses of the stresses during a seismic event with the snubber removed indicated the ASME code requirements were met and there was considerable margin between the calculated stresses and the minimum code requirements.
The inspector concluded that the assumptions made to support the removal of the snubber during the modification work were valid. However, performance of
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the seismic calculation during the modification design to document the bases for the assumption would have eliminated confusion as to the existence of an engineering evaluation to support indefinite operability of the EDGs with the snubber removed.
The modification installation sequence was good in that it permitted upgrading of the exhaust supports while maintaining the EDG operable.
FCR 93-0203 EDG Outout Ratina Voorade The purpose of this modification was to upgrade the horsepower rating of the EDG engines from 300 hp/ cylinder to 350 hp/ cylinder to support an increased electrical generator output rating. The increased rating will provide additional margin between the current EDG bus loadings and the EDG output capacity.
The upgrade will also provide additional margin to support the addition of planned and unplanned electrical loads on the emergency buses.
The engine upgrade is accomplished by-
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replacement of the cylinder liners, pistons, turbocharger, blower and blower drive, fuel injection nozzles;
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eliminating the air inlet check valve assembly and control mechanism, and;
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conversion of the turbo-blower arrangement from a parallel to series configuration.
The engine support system modifications include:
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replacement of the lube oil cooler tube bundle;
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replacement of the engine mounted intercoolers, and;
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replacement of the current transformers and associated protective and
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metering relays.
As part of the modification process a spare EDG and generator set was sent to
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i the manufacturer to receive this modification and to undergo extensive testing at the upgraded horsepower rating.
The inspector reviewed the safety evaluation associated with this modification j
and performed a field inspection of the only EDG that has been modified to
date, 11 EDG. The inspector found that the safety evaluation was thorough and of good quality. No deficiencies were noted during the plant walkdown. The results of the post-modification testing on the 11 EDG and the spare generator set will be reviewed during a future inspection.
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The inspector reviewed Administrative Procedure MD-1-100, " Temporary Alterations," and found that it provided good controls for the development, review, approval, installation and removal of temporary plant modifications.
The inspector also reviewed the temporary alteration documentation for several temporary alterations and/or observed the installation of temporary alterations in the plant.
The temporary alterations reviewed were:
1-94-85 Reverse Logic on 1-PIA-118, 1-93-26 Clamtrol Injection on Saltwater System Header,
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i 1-94-71 Install Temporary Test Gauges for Service Water Heat Exchanger.
The inspector found that the temporary alterations received proper technical reviews and safety evaluations and that the installations were of a good quality and the temporary equipment was properly identified. The number of temporary modifications was not excessive and actions were being taken to eliminate the cause for those already installed.
5.0 ENGINEERING INVOLVEMENT WITH TECHNICAL ISSUES The inspector reviewed recent plant technical issues to evaluate the engineering involvement and effectiveness in resolving these issues.
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Issue Report 32-694 - 11 EDG Trio This issue report documented a trip of the 11 EDG during a slow speed start when the jacket water cooling / exciter switch was positioned from the " slow speed start" to the " automatic" position. The inspector reviewed this issue with the system engineer and determined that plant engineering had thoroughly
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investigated the problem and identified the root cause to be voltage spikes (from DC relay coils) that occur when the switch is operated. The effects on automatic operation of the EDG during an accident had been reviewed and it was determined that this problem was not of concern during automatic EDG starts
and therefore the ability of the unit to perform its safety function was not impaired. The engineers obtained technical assistance from the EDG t
manufacturer in assessing the root cause of the problem. The vendor has been
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asked to review the entire circuit and provide a proposed modification to eliminate the identified voltage spikes and other possible problem areas.
Issue Report 32-265 - Safety Valve leakaae This report was written to document a problem with seat leakage on the reactor coolant system relief valves that occurred following plant heat-ups and following a pressure transient. During interviews with the system engineer the inspector found that the problems had been thoroughly investigated and many possible root causes and contributing factors had been explored. As in the previous example, the component vendor was consulted for technical assistance in resolving the problem. At the time of this inspection the j
investigation was continuing in an effort to establish the best method for i
lift testing the valves to eliminate routine testing as a contributing cause of the problem.
(See Inspection Report 94-19 for more detail).
.C_pncl u si on The inspector concluded that engineering support for recent issues was very good. Troubleshooting and root cause investigations were very thorough.
The use of equipment vendor technical expertise was appropriate while the system engineer maintained ownership of the overall root cause analysis effort.
The system engineers were found to be very knowledgeable and were well informed of other industry experience with similar equipment.
6.0 MANAGEMENT OVERSIGHT AND SELF-ASSESSMENT The inspector noted that there were numerous actions that been taken and self-assessments that had been performed to improve the performance of the engineering organizations. These include:
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establishment of the plant testing section within the plant engineering department;
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performance of a plant modification program self-assessment;
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increase in the analytical capabilities of the engineering department personnel;
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the in-house development of a computer based trending program for the system engineers by the plant engineering staff;
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the use of a troubleshooting response team approach to address significant plant material problems; and,
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the use of an engineering process improvement team to improve the engineering department efficiency and effectiveness.
The program changes that have been implemented are relatively recent, and, similarly, the recommendations resulting from the self-assessment activities have not been implemented to any significant extent. Therefore, the effectiveness of these changes and assessments cannot be programmatically assessed at this point. However, the inspector concluded that the station management has demonstrated a commitment to continued improved performance within the engineering groups.
7.0 EXIT MEETING
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The inspector met with the licensea personnel, noted in the Attachment, at the conclusion of this inspection on October 7, 1994, and summarized the inspection scope and the inspection results. The licensee acknowledged the inspection findings at the exit meeting.
The licensee did not indicate that proprietary information was involved within the scope of this inspection.
Attachment:
Persons Contacted l
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ATTACHMENT Persons Contacted Baltimore Gas and Electric Company A. Anuje Supervisor, Quality Audit Unit
C. Ashley Plant Engineering
A. Broch Senior Engineer, Quality Audit Unit K. Cellars General Supervisor, Design Engineering
P. Chabot Superintendent, Technical Support J. Crunkleton Design Engineering S. Davis Plant Engineering P. Doran Design Engineering J. Drumgoole Operations M. Gahan Design Engineering J. Gines Plant Engineering
R. Gradle Compliance Engineer P. Katz Manager, Nuclear Engineering W. Kemper Principal Engineer, Prir.cipal Engineer
W. Lippold General Supervisor, Technical Services Engineering
S. Loeper Senior Engineer, Plant Engineering T. Luppold Plant Engineering C. Nolan Design Engineering
M. Polak Principal Engineer, Plant Engineering
B. Rudell General Supervisor, Project Management M. Siewertsen Plant Engineering S. Smith Plant Engineering V. Spunar Plant Engineering R. Sydnor Principal Engineer, Electrical Engineering
H. Valenta Independent Safety Engineering Group
J U. S. Nuclear Reaulatory Commission P. Wilson Senior Resident Inspector F. Lyon Resident Inspector
i Denotes those present at the exit meeting.