ML20034A813
| ML20034A813 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 04/12/1990 |
| From: | Mike Williams NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Novak T NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| References | |
| NUDOCS 9004240378 | |
| Download: ML20034A813 (6) | |
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UMTED STATES NUCLEAR REGULATORY COMMISSION I
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APR 11 1990 MEMORANDUM FOR:
Thomas M. Novak, Director l
Division of Safety Programs Office for Analysis and Evaluation i.
of Operational Data j
FROM:
Mark H. Williams, Chief i
Trends and Patterns Analysis Branch Division of Safety Programs Office for Analysis and Evaluation j
of Operational Data
SUBJECT:
SUMMARY
OF FEBRUARY 28 - MARCH 1, 1990 MEETING WITH l
NORTHEAST UTILITIES REGARDING MAINTENANCE INDICATOR l
DEVELOPMENT j
1 i
On February 28 - March 1,1990, staff from AEOD, Northeast Utilities (NU),
r NU's operating companies, and NUMARC met at the Northeast Utilities offices in
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Berlin, Connecticut to exchange information on maintenance indicators. This meeting was part of the NRC/ Industry Maintenance Indicator Demonstration
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Project. A list of meeting attendees is contained in Enclosure 1.
provides the meeting agenda. On March 1,1990, the staff also toured the Haddam Neck nuclear plant.
The NRC staff presented the detail and logic which were followed during the development of the staff's proposed maintenance Indicator (MI). The purpose i
of this presentation was to familiarize utility personnel with all of the:
detail necessary for understanding the proposed indicator, i
In their opening remarks, NU discussed their management approach for the Millstone and Haddam Neck sites.
Each unit at each site is operated as an i
independent entity under the direction of the unit superintendent. Within this framework of independence, each unit has its own maintenance staff and facilities, and tracks cents per kilowatt at the bus bar. However, certain major aspects of the maintenance policy are established at the corporate level.
For example, it is NU's policy that their nuclear plants are not allowed to enter a limiting condition for operation (LCO) solely for the purpose of performing planned maintenance.
NU also has established a system-wide Production Maintenance Management System, or PMMS.
PMMS, which was first placed into operation almost ten years ago on a. phased implementation basis, is now almost completely implemented, and is used to track maintenance at all of their electrical generating stations, fossil as well as nuclear.
It is a computerized maintenance tracking system with fairly extensive capabilities.
NU has used PMMS to: (1) identify plant equipment by means of a system-wide common nomenclature, (2) establish a dedicated planning function at each of their generating facilities, (3) establish a common maintenance work order mechanism across facilities (4) provide a uniform work priority system, (5) provide resource forecasting and tracking on a consistent system-wide basis, and (6) provide a database of production-related information 4
in support of management decisions.
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. There is an important difference between PMMS and the staff's proposed indicator. PMMS tracks work orders and associated information. The staff's proposed indicator tracks equipment failures.
In order to extract failure data from PMMS, engineering analysis suppor ted by standardized guidance, such as found in NPRDS, is recv. red.
NU employs PMMS to purat6 the PMMS Performance Report on a quarterly basis, This report trends a a mber of indicators which NU uses to monitor maintenance performance et their p*. ants.
The contem cf the PMMS Performance Report are as follows: (1)PreventiveMaintenancePerceritApe,(2)CorrectiveMaintenance 4
Backlog, (3) CM Backlog Indicator, (4) Preventive Maintenance Performance, (5) Twenty Most Worked on Components, (6) Ten Most worked on Systems, and (7) Rework Percentage. Performance Indicators have been used in the NU organization as management tools for about five years.
NU considers Items (1), (3), and (7) above their primary maintenance indicators. The Preventive Maintenance Percentage displays a trend of the preventive work accomplished by a task department as a percentage of the total-maintenance work. The CM Backlog Indicator is an indicator which was developed internally by NU. This indicator displays a curve of CM work that indicates the condition of the work backlog and the clearing rate time constant. This consists of the number of priority 3 non-outage CM work orders that are open at a point in time. This process indicator is not used to provide diagnostic feedback to the organization at the working level. The Rework Percentage displays a trend of CM and other work orders that failed a retest by operations by quarter.
which contains (1) quarterly Utility (Performance Report for NU management NU also produces a capacity factor, 2)forcedoutagerate,(3) thermal performance (unit heat rate), (4) LERs, (5) unplanned automatic reactor trips, (6) plant design change evaluation status, (7) plant design change request status, (8) solid radioactive waste generated, (9) collective man-rem exposure, (10) total skin and clothing contaminations, (11) PMMS Indicators #1 and #3, (12) NRC inspections - violations and severity level, (13) outstanding INPO recommendations, (15) NE80 contractors, and (16) Enforcement conferences.
During a discussion about maintenance during outages, NU stated that each of l
itsfourunits(HaddamNeck,MillstoneUnits1,2,and3)preparesanoutage report 30-60 days after the completion of a refueling outage which documents lesson learned during the outage. Within the NU organization, outage planning is done on a unit level, as opposed to the corporate level. Usage of the l
NPRDS database by the NU organization was also discussed. Currently, there is l
a task force within the organization evaluating how NPRDS could best be used to enhance plant operations.
In the past, the NU organization has not used HPRDS data very much, and since it is prepared at the corporate level, unit maintenance managers are generally not familiar with the NPRDS data for their units.
I Prior to the meeting NU was provided with examples of NPRDS-reported failures, used in constructing the proposed indicator, that the staff categorized as i
. maintenance related. The discussion of the history behind these failures indicated that plant staff were aware of component performance problems and had often made various adjustments to the maintenance programs in response.
However, the utility determination that the performance problem originated in a marginal application of a component design resulted in their concluding that the failures were not related to maintenance. Several examples are discussed below. Since the frequency of such failures is being controlled by the maintenance program, the staff believes an increase or decrease in such failures is a measure of maintenance effectiveness.
There were a number of failures of a reactor recirculation pump pressure switch at Millstone 1 that the utility had attributed to wearout in the NPRDS failure records. On other occasions, the same switch had drifted out of specification due to unknown causes.
The NU staff explained that this sarticular switch was a design problem that had existed since the plant was auilt.
It was essentially a misapplication of design which utility management had made a decision to live with, and had charged the maintenance department to keep the equipment operating, given this deficiency. NU stated that a temporary solution to the problem had been implemented. This consisted of an increased surveillance frequency which was established to catch the instrument drif t while it was still in the incipient stage before the instrument's function became degraded.
Another example consisted of three failures of main feedwater pump seals at Millstone 3.
In this case, according to the utility, the original pump seal design was marginal, especially at low flow conditions, when flashing led to overheating of the seal and subsequent failure. As explained, this was a l
misapplication of design, for which utility management had decided that continuing to fix seal failures was more cost-effective than making a major design modification. The maintenance organization was then faced with the responsibility of keeping the pumps in operating condition in spite of the seal problem. These failures were either categorized as due to unknown causes or attributed to design problems.
During the meeting, NU staff expressed a number of concerns about the usefulness of the p(roposed indicator. fielding questions from the NRC and various PUCs The need for resources to res another indicator
, with the likely outcome that these resources would be diverted from existing staff now devoted to utility performance trending, was a major concern.
In the NRC staff's view, the intended use of the proposed indicator should help allay this concern. The utility staff also felt that the proposed indicator was difficult to interpret, and offered little diagnostic information for corrective action.
As a programmatic indicator, diagnostic capability was not a prime concern originally, but comments from other Demonstration Project participants have resulted in modifications, such as cutting the indicator by component type, to enhance its usefulness to plant staff.
The utility staff also felt that the quality of NPRDS reporting may not be high enough for this important use. The tendency for NPRDS data to show concentrations of failures discovered in outages, and the potential for penalizing proactive maintenance if incipient conditions were reported as
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degraded failures were raised as issues. NRC staff actions to adjust indicator 1
interpretation based on various segments of.the fuel cycle, and examination of reporting patterns-in interpreting the indicator were cited by the staff as potential remedies for these concerns.
.j Lastly, NU staff were concerned.about use of a single indicator to track 1
maintenance. the staff explained that no indicator is used in the absence of j
other information, including other indicators and information from various types of inspections.
Further, the proposed indicator was developed as an example of the type of indicator needed, and was not intended to be the only indicator based on component failure data.
\\A Mark H. Williams, Chief Trends and Patterns Analysis Branch Office for Analysis and Evaluation of Operational Data
Enclosure:
As stated cc:
M. Boyle, NRR q
G. Vissing, NRR D. Jaffe, NRR A. Wang, NRR W. Raymond, RI J. Shedlosky, RI D. Haverkamp, RI Distribution:
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'1 0FFICIAL RECORD COPY
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ENCLOSURE 1
-ATTENDANCE LIST q
FEBRUARY-28-MARCH l',
1990-MEETING WITH NORTHEAST UTILITIES.
H&gg AFFILIATION Bob Dennig.
NRC/AEOD' T..M. Novak NRC/AEOD Patrick O'Reilly NRC/AEOD Mark Williams NRC/AEOD
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Thomas Laats EG&G-Idaho' Howard Stromberg EG&G-Idahot Peter M. Austin
' Northeast Utilities Mike Ciccone Northeast 1 Utilities 4
Tom'Dente Northeast Utilities-
[
Neil Herzig _
Northeast Utilities i
William J. Nadeau Northeast Utilities Wayne D Romberg Northeast Utilities; Jere LaPlatney Connecticut Yankee Atomic Power.
Neil Bergh Northeast Nuclear / Energy Company Peter J. Przekop Northeast Nuclear Energy Company Ron Rothgeb Northeast Nuclear Energy Company Walt Smith NUMARC Tom Tipton NUMARC l
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ENCLOSVRE-2 1
AGENDA ~
4 FEBRUARY 28 - MARCH l, 1990 MEETING WITH NORTHEAST UTILITIES / NORTHEAST 1
NUCLEAR ENERGY COMPANY REGARDING MAINTENANCE INDICATOR $
4 1
(1) NRC Presentation - Performance Indicator Development, Analysis Assumptions J
and Purpose of Meeting.-
(2) Discussion of Interim Indicator Results.
(3) NPRDS Reporting of Component Failures. Involving Outage-Dominating Equipment'..
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'(4) Root Cause Analysis of Individual Component Failures of Outage-Dominating
-Equipment..
(5) Discussion cf Northeast Utilities / Northeast Nuclear Energy Programs / Approaches for Trending Equipment Failures and Failure causes as They Relate to Main-tenance.
(6)-ComparisonofMaintenanceTrendInformation.
(a) Trends Calculated with the NRC's Indicator.
(b) Trends Calculated with Northeast Utilities / Northeast Nuclear Energy Indicator (s).
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