IR 05000317/1992028
| ML20125C167 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 11/30/1992 |
| From: | Gray E, Kaplan H, Mcbrearty R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20125C160 | List: |
| References | |
| 50-317-92-28, 50-318-92-28, NUDOCS 9212110078 | |
| Download: ML20125C167 (8) | |
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U.S. NUCLEAR REGULATORY COMMISSION
REGION I
REPORT / DOCKET NOS. 50-317/92-28 50-318/92-28 LICENSE NOS.
DPR-53 DPR-69 LICENSEE:
Baltimore Gas and Electric Company FACILITY NAME:
Calvert Cliffs Units 1 and 2 INSPECTION AT:
Lusby, Maryland INSPECTION DATES:
November 3-6,1992 INSPECTORS:
M A htJw 11-2 2 - h.
H.1. Kaplan, Sr. Reactor Engineer, Date Materials Section, EB, DRS 4L4ar f.7c /%anW 71 A n m z R. A McBrearty, Reactor Edineer, Date Materials Section, EB, DRS APPROVED BY:
///Jo /f L E. Harold Gray, Chidf, Materials Section, Date Engineering Branch, DRS A_reas Insocctedi An inspection was conducted of the licensee's erosion / corrosion (E/C)
r monitoring program, plant water chemistry and the inservice inspection program. The inspection was conducted to ascertain whether the program conformed to applicable code and regulatory requirements, and whether the activities were performed in a way that confirms the plant's acceptability to continue operation.
Res!!13: The E/C program is generally good. Previous inspection results confirm that the program is effective in finding defective components and performing its intended function.
Tb" !i program conforms with code and regulatory requirements. The chemistry control for tin pc.ma y water in the RCS system was found to be effective and conform to Technical Specitication requirements. For normal operating modes the key parameters were consistently well below the specified limits. The chemistry control of the steam gererator-
- secondary side was also found to be effective and the chemistry results compared favorably
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with other utilities using industry standards.
9212110078 921204 PDR-ADOCK 05000317
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2-1.0 EROSION / CORROSION (E/C) PROGRAM (Inspection Procedure IP 49001)
1.1 Background Concern regarding erosion and corrosion in balance of plant piping systems has been heightened as a result of the December 9,1986, feedwater line rupture that occurred at Surry Unit 2. That event was the subject of NRC Information Notice 86-17,Bulletin 87-01 and Generic letter (GL) 89-08. The GL specifies that all licensees provide' assurances that'a program, consisting of systematic measures to ensure that 3rosion/ corrosion does not lead to degradation of single and two phase high energy carbon steel piping systems, has been implemented.
A formal inspection program was established at Calvert Cliffs in 1984. Inspection loudons l-were established and prioritized using plant and industry experience and plant characteristics l
including piping geometry and material, flow velocities, system pressure and temperature.
Criginally, water chemistry characteristics were not used, but were included in the process after implementation of Materials Enfneering and Analysis Implementing Procedure ME&AIP 5.05, " Secondary System Piping bosion/ Corrosion Inspection Procedure.".When the present program was establisbd, as discussed in the licensee's response to Bulletin 87-01 L
and Generic 12tter 89-08, plant historical data, E/C rates and prwious piping replacement -
information was available from the 1984 program. No computer based program such as the
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EPRI generated "CHECMATE" for system selection and prioritization was used at that time.
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The large act "nulation of plant historical data, measurements from 1984 to the presert, l
l permits accurate wear rate predictions. Current plans are to initiate the use of
"CHECMATE" by the middle of 1993.
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1.2 Response to Bulletin 87-01 and Generic Letter (GL) 89-08 Bulletin 87-01 was issued on July 9,1987, to provide information to licensees regarding erosion / corrosion problems at nuclear plants and requested licensee responses to specific actions defined by the Bulletin.
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l The response to Bulletin d7-01 to the NRC was by letter dated September 9,1987, addressing -
L the actions as requested by the Bulletin.
Generic Letter 89-08 was issued on May 2,1989, and requested licensees to provide assurances that an erosion / corrosion program has been implemented. The licensee responded l
to the GL by letter dated July 19,1989, and stated that a procedure would be in place by
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December 31,1989, to control the E/C program. A followup response, dated l
February 26,1990, in re;:ly to the NRC 9/15/89 letter requesting written notification that the L
program has been fully implemented confirmed that the E/C program controlling procedure L
ME&AIP 5.05 was fully implemented on December 29,1989.
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1.3 Responsibilities The supervisor of Nuclear Inspection Services Unit (NISU) is rerponsible for implementing -
the E/C program at Calve" Cliffs. A description of program responsibilities is found in L
ME&AIP 5.05. Nuclear inspection Services is responsible for selecting and prioritizing l
systems and components for the E/C program. Inspections, ultrasonic thickness measurements, are performed by the licensee's inservice inspection contractor and the results are evaluated by the E/C engineer using pre-established acceptance criteria. The
establishment of tie Nceptance criteria is the responsibility of the E/C engineer. Items l
requiring further evaluation are identified on an Issue Report generated by the E/C engineer and submitted to the appropricte systera engineer who is responsible for performing the evaluation and disposition. The Issue Report is the mechanism by which E/C items are tracked through the licensec's tracking system.
No time constraint regarding the transfer of inspection results from the contractor to the E/C-engineer and subsequently to the system engineer, and the evaluation and disposition of questionable results by the system engineer, was included in the controlling procedure. That apparent programmatic weakness was discussed with licensee representatives during the inspection and at the exit meeting. The licensee acknowledged the inspector's concern.
1.4 Program Implementation Procedure ME&AIP 5.05 controls the E/C program. The procedure identifies the systems
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L included in the program, acceptance criteria, inspection frequency, inspection techniques, prioritization of inspection points and the attributes used for inspection point selection.-
Thickness measurements are taken at the intersecting points of a grid pattern that is marked on the pipe section under inspection. The procedure identifies the appropriate grid size which'
is based on pipe diameter. The procedure, additionally, requires that zero reference points be -
l permanently marked on each inspection point.
Some exceptions to the controlled program were identified:
The NRC inspector noted that the E/C program requires that inspection point EB-01-1005-05 be examined during each Unit I refueling outage to monitor a thin wall area resulting from weld fit-up during the construction of Unit 1. Inspection of the area -
since 1985 has produced confusing results, and data show that the inspections were not l
all performed the same way with similar equipment. Addiuonally, it is unclear from l
the data that the measurements were taken from the same reference point in each case.
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Baseline thickness measurements of replacement piping are performed by the licensee in some cases. The procedure does not address baseline inspections and that _was discussed with licensee representatives as a _way to improve the overall E/C program.
In 1993, when the use of "CHECMATE" is initiated by the licensee, it would be beneficial if plant characteristks such as water chemistry be available to the E/C engineer for inclusion in the "CHECMATE" analysis. There is presently no -
procedure or mechanism that assures that the E/C engineer is made aware of that -
information.
The use of baseline inspections and the importance of plant operating characteristics with regard to the auusacy of "CHECMATE" analyses were discussed with licensee representatives during the inspection and at the exit meeting.
During the 1992 Unit I refueling outage,240 component areas were subjected to E/C examination which resulted in the replacement of 21 components. In addition to that,198 were replaced based on predicted wall loss.
Conclusions The erosion / corrosion (E/C) program at Calvert Cliffs is generally good. A formal E/C monitoring program was initiated at the facility in 1984 and has resulted in a large library of wall thickness data to aid in predicting wear rates and selecting components for the monitoring program. When the use of "CHECMATE" is initiated for system selectica, prioritization, and wear rate prediction, the effectiveness of the program will be enhanced.
Areas where the E/C program could be strengthened include the establishment of time constraints on the flow of data, the full use of baseline thickness measurements, the establishment of a meclenism to assure that the appropriate engineer is made aware of plant -
operating characteristics and changes to those characteristics, and oversight of the inspection contractor regarding performance of E/C inspections and data reporting for reproducibility.
2.0 INSERVICE INSPECTION (FSI) PROGRAM (IP 73051)
Selected items identified on the long term plan change recor
- Unit 1, the ISI 10-year long term plan and the ISI schedule of exam: nations for the Unit 2.. 3 refueling outage were selected for inspection. The inspection was performed to ascertain that ISI programmatic changes made during previous Unit I refueling outages were included on the permanent 10_
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year plan and in the licensee'< computer da'a base, and that the examinations listed by the 10-year plan for the 1993 Unit 2 refueling outage were scheduled to be performed during the-
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The items on the Unit I change record were determined to be included on the permanent 10-.
year long term plan and in the computer data base which provides confidence that the examinations will be performed at the appropriate time.
The 10-year program long term plan identifies the examinations that should be performed during the 1993 Unit 2 refueling outage. Items listed for the reactor pressure vessel, reactor coolant system, pressurizer and the pressurizer surge line were confirmed to be included in the inspection plan for this 1993 outage. This was established by comparing the 10-year plan with the Unit 21993 outage schedule of examinations.
The inspector determined that a.1 of the selected items were included on the outage
examination schedule for performance during the cutage.
Conclusion Changes to the ISI plan, which are found to be necessary dcring refueling outages are entered on th; permanent record, and planned examinaticas are scheduled for performance at the appropriate time, thus providing confidence that the ISI program is maintained and tracked within ASME Code Section XI and regulatory requirements.
3.0 WATER CIIEMISTRY (IP 84750)
3.1 Scope The inspector reviewed Unit I and Unit 2 primary water and secondary side steam generator chemistry records for the period between January 1,1992 through November 2,1992.
3.2 Findings The primary water reu!!s for the reactor coolant system (RCS),.which included fluoride, chloride and dissolved oxygen, were found to be consistently well below Technical
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Specification (TS) limits. The fluoride, enloride and dissolved concentrations were consistently reported in the ppb (parts per billion) rann as compared to the TS steady state limit of s.15 ppm (pans per million). The flu _oride ranged between 2,0 and 34.6 ppb, the
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chloride between 2.0 and 8.8 ppb, and dissolved oxygen at 10 ppb. The testing frequency -
was daily, thus meeting the TS 9equirement of once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. For the secondary side, for example, Calvert Cliffs reported sodium concentrations of less thu 10 ppb for SG-11 in -
this same period. The chemistry activities were controlled by various procedures. The principle specifications are CP-204 for primary water RCS system and CP-21'7 for secondary-waar systems. The requirements covering quality assurance imd quality control are specified-in CP-103. An overall review of these procedures indicated that they were written in great detail with appropriate data forms.
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The inspector witnessed the analysis of a fluoride and chloride sample obtained from tiie_RCS cold leg of Unit 2. The instrument (Dionex) calibration and control sample analyses-attendant with the Unit 2 sample were found to conform to the aforementioned CP-103 requirement. The instrument calibration check was performed on 10/9/92 and the control standard immediately prior to runnin~g the RCS cold leg analyses. The fluoride and chloride control sample analyses were 10.4 and 9.30 ppb, respectively. The analyses of the cold leg sample were 3.99 ppb for fluoride and 3.37 for chloride.
The training record for the laboratory technician who performed the cold leg sample ~ analysis was found to be continuous and covered a whole range of activities and subjects including the -
use of the Dionex instrument. The supervisory personnel were found to be knowledgeable and attentative to the activities in progress.
The inspector noted the excellent secondary side chemistry oerformance index (CPI) results and the positive round robin test results relative to other utilities. The CPI index for Units 1
& 2 was.12.26 and.16
.29, respectively, which exceeded the goals established for Units 1 & 2. The INPO power industry median reswtr alged from.21
.34. The CPI is a unitless number that attempts to quantify the chemical impurities which affoct SGs.- It is the ratio of three parameters; condensate oxygen, SG sodium and SG cation conductivity. The lower the index, the better the performance.
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3.3 Conclusion Chemistry control of the primary RCS system was found 'o be effective and in accordance i.-
with Technical Specification requirements. Chemittry control of the SG secondary side was found to be in accordance with industry standards.
UNIT 1 SURFACE CONDENSER The inspector reviewed a met.alturgical report on the failures of AL-6X stainless steel tubes
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removed from the Unit I surface condensers. On the basis of the evidence presented in the report, the inspector concurred with the Calvert Cliffs conclusion that the failure was caus-A
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by localized corrosion under deposits.
The inspector noted that the AL-6X performance may have been better had the tubes been solution annealed after forming and welding. The following information concerning the Units 1 and 2 surface condecsers is noted.
Units 1 and 2 condensers were retubed in 1982 because of excessive corrosion of the -
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L 70-30 copper-nickel tubes.
js Unit 2 was retubed with Titanium; Unit I with welded AL-6X stainless.
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Of the 49500 Unit 1 Ale 6X tubes in six waterboxes,1.9% (963) have been plugged
because of eddy current indications greater than 60% throughwall.
On the basis of the report, Calvert Cliffs concluded that retut,ing of Unit 1_with
Titanium tubine vas not warranted for the next refueling since 95% of the AL.-6X tubes had no detectable defects.
5.0 EXIT MEETING The findings of the inspection were discussed with the licensee representatives at tne exit meeting on November 6,1992, as indicated in Attachment 1. Within the scope of this inspection, no violations were observed.
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A1TACIIMENT 1
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Persons Contacted Baltimore Gas & Electric Company
- P. T. Crinigan, General Supervisor - Chemistry
- H. D. Enoch, Erosion / Corrosion Engineer K. M. Hoffman, Principal Engineer - Nuclear Inservice Inspection Unit
- T. Lupold, PES /SSEU
- W. Maki,4mpiiance "ngineer D. Muth, Complianct agineer
13. Radford, Plant Engineering
- C. W. Smith, Plant Engineering D. Song, Inservice Inspection Engineer
V. Spumar, PE SSEU
- J. Volkoff, Compliance Engineer U.S. Nuclear Regulatory Commission C. F. Lyon, Resident Inspector
Indicates attendance at the exit meetirg,
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