IR 05000317/1982011
| ML20053E903 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 05/19/1982 |
| From: | Durr J, Reynolds S NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20053E899 | List: |
| References | |
| 50-317-82-11, 50-318-82-13, NUDOCS 8206100193 | |
| Download: ML20053E903 (5) | |
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Calvert Cliffs Unit 1 & 2 U.S. NUCLEAR REGULATORY COMMISSION
REGION I
50-317/82-11 Report No.
50-318/82-13 Docket No.
50-317 & 50-318 License No. DPR-53 & DPR-69 Priority
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Category A&A Licensee:
Baltimore Gas and Electric Company P.O. Box 1475 Baltimore, Maryland 21203 Facility Name: Calvert Cliffs Units 1 & 2 Inspection at:
Lusby, Maryland Inspection conducted: May 6-7, 1982 Inspector-t/c/c/
dp 9<2 h (/0. Reynolds, Jr., Reactor Engineering
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Inspector date signed date signed 5/j9 7J Approved by:
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urr, Chief, Materials and Processes
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Section Inspection Summary:
Inspection on May 6-7, 1982 (Combined Report Nos. 50-317/82-11; 50-318/82-13 Areas Inspected: Unannounced inspection by regional based inspector of salt water intrusion into the steam generator and primary water leakage induced corrosion pro-blems associated with the RCP suction elbow weld and closure studs.
The inspection involved 13 inspector hours onsite and 5 inspector hours at the Regional Office by one NRC regional based inspector.
Results: No areas of noncompliance were identified.
8206100593 820524
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PDR ADOCK 05000317 G
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DETAILS
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1.
Persons Contacted I
Baltimore Gas and Electric Company J. Tiernan, Manager, Nuclear Power
B. Ruddell, ISI Engineer G. E. Brobst, General Supervisor - Chemistry
J. A. Mihalcik, Nuclear Fuel Management Engineer
J. T. Carroll, General Supervisor - Operations
L. B. Russell, Plant Supervisor
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P. T. Crinigan, Senior Engineer - Chemistry
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Unit #1 Steam Generator (Unit 1)
Combined Inspection Report 50-317/81-15 and 50-318/81-14 reported an intrusi'on of salt water into the condensate system of Unit 1 through an unplugged tube hole in the condenser tubesheet on July 14, 1981.
The licensee's evaluation of the intrusion incident and corrective actions were also reported in the inspection report.
This report indicates the results of further review of the event in response to Inspector Follow-up Item (317/81-15-04) by a Regionally
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Based Inspector.
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Unit I was restarted on July 21,19f.,1 following draining, flushing and cleaning and establishment of water chemistry within specification
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limits. The NRC inspector eviewed plots of steam generator bulk water chloride content and idium hideout return following the July 14, 1981 chloride intrusion. The hit aout return analyses during large decreases in steam generator heat flux on shutdowns on 8/31/81, 9/15/81, 10/24/81 and 11/25/81 indicates no significant change in hideout following the
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salt water incident.
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The water chemistry analyses interpreted by the licensee prior to the current outage indicated that special crevice flushing procedures for the steam generator were not required.
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Calvert Cliffs Unit 1 & 2
The NRC Inspector reviewed the change in Unit 1 main condenser tube material from 70-30 copper-nickel to AL6X austenitic stainless steel and observed the retubing in progress. The tube material change was accomplished to improve the reliability of tube service performance to minimize necessity for tube plugging. Service failures of the 70-30 copper-nickel were attributed to inlet end erosion, partially blocked tube erosion, construction dencs in the steam impingment area and deposit attack.
General corrosion was not a problem.
The NRC Inspector reviewed the procedures established for ISI Eddy Current (EC) Testing for the steam generator tubing. The Tech Spec (Appendix A to DPR-53 dated 2/11/77, paragraphs 3.4.5 and 4.4.5.0 to 4.4.5.5) requires that 6% of the tubes in one of the two generators be inspected (a total of 630 tubes at this outage). The licensee will inspect approximately 1,000 tubes in each steam generator.
Inspection of the tubes will be conducted with 100 KH differential, mixed 400 Z
KH and 100 KH differential, 100 KH in addition to the regular 400 Z
Z Z
KH differential standard ASME SCXI technique (BG & E NDE 5.506 Rev.
Z O,4/12/82). A 25 KH absolute technique will be used to develop Z
sludge profile data. The NRC Inspector reviewed the suspected denting areas and areas where outer surface pitting would occur if additional degradation resulted from the chloride intrusion. The evaluation of the EC data will be made by Zetec EC personnel experienced in interpre-tation of the Millstone 2 pitting EC signatures.
The #12 steam generator will be given a helium leak test to locate the
<2 gallon per day primary to secondary leak. The test will employ 30 PSIG helium on the shell side and a mass spectrometer sniffer on the tubesheet. The test will be conducted in accordance with BG & E Technical Support Procedure 72 Rev. O dated 4/23/82.
Decision to extend this test to #11 steam generator has not been finalized.
The Calvert Cliffs steam generators have shown reliable corrosion performance (no tube EC indications >40%).
Contributing to this i
performance is the minimization of copper in the system due to all-l ferrous feedwater heaters, removal of copper from the condensate in the filters upstream of the demineralizers, high volume of blowdown
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permited by the blowdown recovery system and a very small " fluffy" sludge pile. The Unit I steam generators have indicated denting in
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areas associated with "hard spots" in the #9 and #10 tube support plates since the Fall of 1980. The tube support plates attachments to the wrapper (baffle wall) will be modified during this outage to minimize the denting tube deformation by removal of lateral restraint of the tube support plates.
The tube support plate modification will be the same as previously accomplished at Millstone 2 and St. Lucie (operating plants) and other new CE steam generators.
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Calvert Cliffs Unit 1 & 2
The licensee has committed to follow th) intent of the EPRI (Steam Generator Owners Group "PWR Secondary Water Chemistry guideline")
which is a decision tree for secondary side water chemistry limits which incl 6 des various phases of startup. These guidelines prohibit continuance of startup until the chemistr> limits for the preceding phase are satisfied.
Chemistry data review indicates no evidence of chloride ion hide out from the salt water intrusion on July 14, 1981. The licensee has conducted remedial actions to minimize the occurrence of condenser tube problems and has modified operating procedures to preclude continu-ation of startup when unusual off chemistry conditions occur. Steam generator tubing degradation attributable to the salt water intrusion will be made during ISI EC testing which will concentrate on inspection of the areas sensitive to pitting and denting.
Review of the ISI EC testing will be made by the NRC inspection.
No violations were identified.
3.
Unit 2 Reactor Coolant Pump (RCP) Suction Pipe Attachment Corrosion (Unit #2)
The NRC Inspector reviewed the licensee's inspection, evaluation and repair methods for the subject corrosion problem reported in 50-318/81-02 on the Byron-Jackson RCP. The RCP suction elbow weld is shv.<n in CE drawing 233-582 Detail E (A-7). The elbow is a fabricated, roll bond clad, SA 516 " claim shell" design.
The Inspector Follow-up Items indicated in 50-318/81-02 were closed in combined report 50-317/81-07/ 50-318/81-0/. The elbow clad metal.is a SA 240, Grade 304L. The pump casing is cast CF8M and the safe end (suction nozzle)
on the pump casia is centrifugally cast CF8M.
The pump suction nozzle to elbow weld joint is made with Inconel type filler metal.
Two (22A and 228) of the four pumps showed the effects of galvanic corrosion on the carbon steel side of the interface between the Inconel type weld and elbow. The affected area is completely insulated.
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The licensee conducted corrosion groove depth measurements with a pit gauge and material thickness measurements adjacent to the groove by
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l ultrasonic gauge. The NRC inspector reviewed the data on depth L
measurements. The minimum thickness following blending of corrosion groove and penetrant testing of the blended area to a "no indication" i
criteria exceeded minimum wall thickness requirements. The blending
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of the corrosion defect was conducted in accordance with SCXI IWB-4310.
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Calvert Cliffs Unit 1 & 2
The leakage of boric acid also caused dissolution corrosion of the closure studs on the coolant pumps in both Units as reported in 317/80-20 and 317/80-26 Inspection Report. The evaluation of corrosion on the studs by destructive testing indicated that the studs retained sufficient load-carrying capacity in the corroded condition; however,-
for additional reliability the licensee replaced the affected studs.
The NRC Inspector has no further questions on the bimetal weld corrosion
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problem and corroded studs.
This item is closed.
No items of noncompliance were identified.
4.
Exit Interview On May 7, 1982 an exit interview was held with members of the licensee's staff denoted in paragraph I (*).
The inspector discusced the scope and
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findings of the inspection.
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