IR 05000213/1988009

Insp Rept 50-213/88-09 on 880516-20.No Violations or Deviations Noted.Major Areas Inspected:Steam Generator Inservice Insp,Secondary Water Chemistry Control,Radiation Protection Results & Insp of Other Secondary HXs

ML20151Q681
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	07/22/1988
From:	Strosnider J, Winters R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
Shared Package
ML20151Q679	List: IR 05000213/1988009 ML20151Q677
References
50-213-88-09, 50-213-88-9, NUDOCS 8808110253
Download: ML20151Q681 (12)

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U.S. NUCLEAR REGULATORY COMMISSION

REGION I

. Report N /88-09 S Docket'N License-N OPR-61 1 Licensee: Connecticut Yankee Atomic Power Company RR #1, Box 127E East Hampton, Connecticut 06424 Facility Name: Hadam Neck Plant Inspection At: East Hampton, Connecticut Inspection Dates: May 16-20, 1988

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Inspector [: < W. Winters, Reactor Engineer, MPS, EB, date i RS, Region I Approved by: ,

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J/ Stt osnider, Chief, Materials & Processes date

,Jection, Engineering Branch, DRS, RI Inspection Summary: Routine announced inspection on May 16-20, 1988 (Report No. 50-213/88-09)

Areas Inspected: Steam generator inservice inspection, secondary water chemistry control, radiation protection results and inspection of other secondary heat exchanger Results: No violations or deviations were identifie l 8808110253 880720 "

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DETAILS 1.0 Persons Contacted Connecticut Yankee Atomic Power Company

• J. Beauchamp, Supervisor, Plant Quality Services J. Calderone, Inservice Inspection Engineer

• H. Clow, Health Physics Supervisor

• E. DeBarba, Station Services Superintendent

• J. DeLawrence, Inservice Inspection Supervisor L. Laskowski, Inservice Inspection Engineer l S. Matthers, Chemist J. Powell, ALARA Coordinator Hartford Steam Boiler Insurance and Inspection Services Company W. Braden, Authorized Nuclear Inspector Cramer and Lindell Engineers, In T. Gray, Eddy Current Inspector, Level III C. Lindell, Eddy Current Inspection Engineer, level III P. Rubino, Eddy Current Inspector, Level II United States Nuclear Regulatory Commission

• A. Asars, Resident Inspector

• Denotes those ettending the exit meetin The inspector also contacted other administrative and technical personnel during the inspectio .0 Introduction The Haddam Neck Plant, East Hampton, Connecticut has four vertical U-tube Westinghouse model 24 steam generators with integral steam drying equipment. These steam generators were constructed in accordance with the ASME Code, Section VIII, Unfired Pressure Vessels, 1962 Edition. Each steam generator has 3794 SB 163 (Inconel) tubes 3/4 inch 0.D. and 0.055 inch nominal wall thickness. The tubesheet consists of a SA 266 Class 1 (carbon steel) forging 22.625 inch thick clad with SB 163 on the primary side. The tubesheet separates the primary and secondary fluids and contains the ends of the U-tubes that extend into the secondary side of the steam generato Table 1 shows the number of tubes plugged in each steam generatar since initial operation of these unit . . .- . . .

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TABLE 1 Historical Tube Plugging Data Inspection Steam Generator 1 2 3 4 Total 1966 - May 1 2 3 Commercial operation started January 1, 1968 1970 - June 2 2 1972 - June 1 14 15 1973 - August 10 10 1975 - May 8 8 1976 - June 1 1 2 4 1977 - October 1 1 2 1979 - February 1 1 1980 - May 2 2 1981 - October 5 18 2 25 1983 - February 111 106 1 2 220 1984 - August 8 52 6 1 67 1986 - January 12 22 14 13 61 1986 - July 33 38 55 126 1987 - July 57 64 9 223 353 TOTAL 197 301 85 316 899 3.0 References / Requirements Steam generator surveillance activities were inspected to determine -

compliance with the following requirements, commitments and recommendations: Technical Specifications - Steam Generators paragraph 4.1 Final Safety Analysis Report - Steam Generators paragraph 10 PWR Secondary Water Guidelines - Electric Power Research Institute Special Report NP-5056-SR 4.0 Steam Generator Eddy Current Inspection Scope Plans for the next steam generator inspection were reviewed and the methods of data collection and analysis were discussed with licensee personnel. The results of the eddy current inspection of the main condenser, feedwater heaters, and moisture separator reheaters were also reviewe . _ . _ _ _ - _ , _ _ . . _ _ _ _ - - _ _ , _ - . - _ . . - - _ , ~

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Details of the Review The inspector reviewed the data from the past eddy cur ent inspections and interviewed personnel concerning past inspections end plans for future eddy current testing. During the July - September 1987 inspection 100% of the unplugged tubes in all four steam generators were eddy current tested tube end to tube end using a standard bobbin coi In addition a selected sample of tubes in each generator was inspected using a special probe (F*) designed and qualified for inspecting the roll regions in the steam generator tubesheets. An inspection was also performed on all distorted roll transitions _(DRT) -

and distorted roll indications (DRI) using a motorized rotating coil pancake probe (MPRC) The type and scope of this eddy current *

inspection is shown in Table TABLE 2 Type and Scope of Eddy Current Inspection Type Coil / Inspection Steam Generator 1 2 3 4 Bobbin (Tube end to Tube End) 3654 3557 3718 3701 F* (Roll Region Inspection) 14 207 114 415 MRPC (DRT and ORI) 194 4 36 48 Results of the Eddy Current Inspection Table 3 shows the number of tubes with defects greater than 20%

through wal As a result of this inspection the steam generators were in Technical Specification Category C TABLE 3 Number of Defects Greater Than 20%

Defect Location Steam Generator 1 2 3 4 Above Tubesheet 166 1088 463 195 Above Tube Support Plate 191 105 1 At Antivibration Bars 117 54 49 61 Roll Transition Cracks 34 27 156 PWSCC (Hot Leg) 14 207 96 343 PWSCC (Cold Leg) 1 6 16 99 Degraded and Defective Tubes 523 1487 624 855 Total Tubes Plugged (1) 57 64 9 223 (1) In accorda ce with the Hadam Neck Technical Specifications the plugging limit is equal to 50% of the nominal tube wall thickness for tube l l

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Conclusions The eddy current test results indicate a large number of degraded tubes in all four steam generators. This condition merits.close attention in the next steam generator inspections to determine what the trend in tube degradation is. Comparing the number of degraded and defective tubes and the number of plugged tubes in each steam generator it is apparent that the steam generators at the Hadam Neck Plant have not developed sim1'lar patterns for tube degradatio .0 Inspection of Secondary Side Components The inspector interviewed the vendor inspectors and reviewed the inspection results from eddy current inspections performed on the main condenser - waterboxes A, B, C, and 0, feedwater heaters 1A, 18, 2A, 28, 3A, 3B, 4A, 48, SA, 58, 6A and 68, moisture separator reheaters A, B, C and Condenser The 11censee has rettbed all four waterboxes in the main condenser with Sea-Cure type 26-3-3 (high chromium, molybdenum, carbon, ferritic steel alloy) to eliminate copper bearing alloys and improve secondary water quality. Prior to this inspection waterbox B had 230 tubes plugged, waterbox C had one tube plugged and waterboxes A and D had no plugged tubes. As a result of this inspection waterbox B had 4 additional tubes plugged bringing the total in this waterbox to 23 No other tubes were plugged. Approximately 10% of the tubes in waterboxes A, C, and D were inspected and 23% of the tubes in waterbox B were inspected. The only tube damage recorded during the inspection was mechanical damage such as scratches, gouges and other mechanical conditions introduced during tube manufacture or installation, rather than progressive, service induced conditions. Most of this damage had been recorded in previcus inspections of this condense Feedwater Heaters 1A, 1B, 2A, 28, 3A, 3B, 4A, 48, 5A, 5B, 6A, 6B The objectives of the eddy current inspections of the feedwater heaters were:

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To establish overall tube conditions

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To locate and identify any tubes recording damage that may warrant corrective action

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To identify active damage mechanisms

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To compare results from previous inspections and determine if any

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new damage has initiated The addy current technique used was as close as practical to that used in prior inspections to allow direct comparison with previous results and still meet the other objectives or the inspection. The pattern of inspection was chosen based on past inspection results anJ areas of tube degradation found tFrough experience in other similar inspections. The details of these inspections are summarized in Table TABLE 4 Feedwater Heater Total Tubes Tubes Inspected Percent Number Plugged 1A 3148 292 /0 (1)(2)

IB 3148 262 /0 (3)(4)

2A 1300 432 33 0/0 2B 1300 432 33 0/0 3A 712 176 2 /0 (3)

3B 712 179 2 /0 (4)

4A 1246 306 2 /0 48 1272 317 2 /0 SA 1186 319 2 /0 SB .1250 300 24 0/0 6A 2548 382 15 0/0 68 2548 382 15 0/0 (1) Tubes plugged prior to this inspection / tubes plugged as a result of this inspection.

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(2) 24 tubes could not be inspected full length due to internal deposits (visually identified as magnetite)

(3) Fifteen tubes were plugged by the manufacturer prior to installatio ~

(4) 22 tubes could not be inspected full length due to internal deposits (visually identified as magnetite)

(5) One tube had approximately 20% wall loss due to vibrational wear at tube support nine.

(6) One tube had approximately 30% and two tubes had 15% wall loss due to vibrational wear at tube supports seven and eigh The licensee has replaced all 12 feedwater heaters to eliminate copper contamination in the secondary system. Table 5 shows the dates that these Featers were replaced and the alloys used in the tube . _._ ~ _ . , _ . . - . _ . _ - . _ _ _ . _ . _ ..,_ __ .--

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TABLE _5 Year Replaced

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Feedwater' Heater Tube Alloy 1A 1980 439L Stainless Steel

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IB 1980- 439L Stainless Steel 2A 1983 439L Stainless Steel 28 1983 439L Stainless St. eel 3A 1979 304 Stainless Steel 3B 19'/7 -304 -Stainless-Steel 4A 1984 439L Stainless Steel 48 1986 439L Stainless Steel SA 1984 439L Stainless Steel 58 1986 439L Stainless Steel 6A 1986 439L Stainless Steel 68 1986 439L Stainless Steel Moisture Separator Reheaters

.The licensee has replaced the tube bundles in all four moisture separator reheaters (MSRs). MSRs C and D were replaced in 1980 and MSRs in 198 In all cases the replacement tubes were 439L ferritic stainless steel. The objectives of the eddy current test of these units was the same as that for the feedwater heaters. Only the straight portion of the tubes were inspected. Details of the Inspections are summarized in Table TABLE 6 MSR Total Straight lengths Percent Number Lengths Inspected Plugged A 1522 370 2 /0 (1)

B 1522 324 2 /0 C 1430 307 2 /0 0 1430 307 2 /0

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(1) Tubes plugged prict to this inspection / tubes plugged as a result of this inspectio The inspection contractor reported that the majority of the tubes in these units were very dirty and recommended periodic cleaning during outages. The deposits were visually identified as magnetit Conclusions

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Over a ten year period (19/7-1987) the licensee has replaced all of the tubes in the condenser, feedwater heaters and moisture separator i

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reheater The replacements have been made-using non-copper bearing alloys-that will preclude copper contamination of the steam generator tubing. The magnetite deposits found in the feedwater heaters and MSRs is probably caused by air leakage in the condenser combining with the ferrous piping systems du~ing operation. Because these deposits in the tubes of the feedwater heaters and MSRs, if dislodged, enter the shell side of the steam generato-s it is important that the buildup of these deposits be controlled. Continuing inspections such as those performed during the past years will assure these deposits can be removed before they interfere with the safe operation of the plan .0 Data Analysis Scope This inspection was performed to determine the methods and extent of reviews of the eddy current data developed during the testing. It included an assessment of the licensee's system to assure that no defective tube was missed or that any single individual could downgrade an evaluation from a tube requiring plugging or repair to one not requiring plugging or repai Details of the Review The inspector determined through interviews and observation of the '

records that the eddy current inspection vendor performed two-independent reviews of the data by individuals certified as Level II analysts in accordance with SNT-TC ,1 Prior to the inspection the analysts were trained in site specific requirements to assure that there would be consistency in the reporting of defects both between individual analysts and with past inspection This training included work on the steam generator mock-up for those individuals that where required to set up equipment, change probes, et As the eddy current data was generated each tape was duplicated and a copy given to each of the two analysts assigned to review that dat These analysts would then independently review the data and record their results. These interpretations were then reviewed to determine if there were differences greater than the predetermined tolerance When differences greater than these tolerances were encountered the data was reviewed by a certified Level III analys If either of the initial reviewers determined that the defect required a tube to be plugged and the Level III determined that it did not a second Level III review was required befcre the evaluation was reduced to allow the tube to be left unplugged. In general the licensee did not allow downgrades in the severity level, choosing instead to plug such tube .

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Subsequent to the interpretation the data was stored by the licensee by the nuclear plant records section and a copy was given to the steam generator manufacturer.

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Results-The results of.the last eddy current examination are reported in paragraph 4.0 abov Conclusions Based on the above the inspector concluded that the licensee had

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adopted a conservative approach in data analysis by the two independent review process and in the policy of accepting the worst case interpretation of the dat .0 Secondary Water Chemistry Scope Water chemistry data was reviewed as part of this steam generator inspection and maintenance inspection to determine if the licensee was

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Grou The methods of collecting and verifying the accuracy of these data were not included in the scope of this inspectio Details of the Review The Hadam Neck Plant obtains make up water from deep wells located on the plant sit Initial water treatment was with phosphates and this was changed to all volatile treatment in June 1975 with hydrazine additions to control the pH and oxygen. The tube materials in the major components have been changed as described above to eliminate copper bearing alloys in the secondary syste During the past two years the licensee has added on line monitors for sodium, chlorides, and specific conductivity for the blowdown with the recorders in the chemistry laborator '

The instruments for the feedwater and condensate systems have also been upgraded. In the laboratory the methods Ion Chromatography methods for analyzing sulfates, phosphates, and a, ion conductivity have also been upgrade A graphite furnace has been installed to give the capability of measuring sodium to less than one ppb. In line sample points are located af ter the condensate pumps, af ter the feedwater heaters and on the blowdown lines. In addition at each of these sample points the licensee has the capability for removing grab samples. Chemical additions are made after the condensate pump *

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The inspector reviewed the data for secondary water chemistry for the period from January - July 1988 to determine if the licensee commitments and EPRI or owners group guidelines for secondary water chemistry quality were being me Results The results of this review are shown in Table 7 for steady state operations excluding transients and trip TABLE 7 Water Chemistry History January - July 1988 Parameter Feedwater Condensate Blowdown EPRI SG 1 Guide (Blowdown)

Spec Cond, umhos 10.14 Cat Cond., umhos 0.07 0.26 0.8 ma Chloride, ppb 10 (1) 2.1 (2) 10 (1) 20 ma Sodium, ppb 5 (1) 1.1 (2) 5 (1) 20 ma Silica, ppb xygen 3 (1) 3 (1) 5 (1)

pH 9.61 9.66 9.44 8.5- (1) Lower limit of detection (2) In line monitor l Conclusions

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The licensee is operating well within the EPRI guidelines for water l qualit Initiat!ves such as retubing of all major components in the l secondary side, installation of in line monitors and improvements in I

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analysis techniques have contributed to the water quality that has been achieved in the secondary sid .0 Radiation Exposure Radiation data was reviewed as part of this steam generator inspection and maintenance inspection. The methods of collecting and verifying the accuracy of these data were not included in the scope of this inspectio Details of the Review The inspector reviewed the exposure history for the past seven steam generator eddy current inspections and discussed the efforts made to

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reduce exposures with licensee personnel. One individual in the licensee's organization had received r. management award for-his efforts to reduce exposures by modifying the steam generator skirt to allow the use of the skirt as shieldin Results The results of the licensee's efforts to reduce exposures are shown in Table 8. This table shows the exposures received during the last seven steam generator inspection TABLE 8 RADIATION EXPOSURES RECEIVED DURING STEAM GENERATOR INSPECTIONS Description 1979 1980 1981 1983 1984 1986 1987 ECT (rem / tube) 0.058 0.035 0.025 0.025 0.012 0.006 0.005 Plugging (rem / tube) 2.600 2.044 0.770 0.402 0.645 0.587 0.055 Manways(rem /sg) 11.755 9.060 5.865 4.699 5.977 5.039 4.614 Lancing (rem /sg) 14.700 10.192 12.571 8.253 7.865 9.790 5.970 Conclusions Based on the information shown in Table 8 the licensee has significantly reduced exposures for the steam generator eddy current in;pection The modification to the steam generator skirt so that it could be used as shielding resulted in a reduction of exposures of 399 man-rem for the 1987 inspection. This modification will continue to provide significant reductions in future inspection .0 Licensee's Actions on Previous NRC Concerns (Closed) Bulletin 80-08 Examination of Containment Liner Penetration Welds The penetration welds were designed in accordance with ASA 031.1, 1955 ,

edition. All shop and field welds were randomly radiographed in accordance with Paragraph UW-52 of the ASME Boiier and Pressure Vessel Code. Section VIII in effect at the time of construction. In addition the butt welds connecting the forging ring to the iiner sleeve were covered by a weld test channel and leak tested using an air-freon gas mixture injected into the channel. Any leakage detected in excess of 0.5 cubic inches per day required weld repair. All weld joint were designed with backing bars. The inspector confirmed that this testing

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was completed during construction of the plant. A containment integrated leak rate test (CILRT) was successfully performed September 26-28, 1987 trat verified the integrity of the containment penetration weld This CILRT was witnessed by an NRC inspecto This bulletin is close (Closed) Bulletin 88-02 Rapidly Propagating Cracks in Steam Generator Tubes The most recent eddy current ir.spection data (September 1987) has been reviewed as required by Bulletin 38-0 The results of this inspection indicate that a majority of the tubes are dented at the top support plate, and there are some tubes not supported by antivibration bars (AVB). An enhanced leak monitoring program has been implemented at the Hadam Neck Plant. The inspec'.or reviewed the Administrative Technical Specifications and the procedures for the enhanced leak rate monitoring and found them acceptable. In addition the licensee has completed a one dimensional analysis to assess the stability ratio of the unsupported tubes and is in the process of performing a three dimensional analysis of these tube This bulletin is close .0 Management Meetings Licensee management was informsd of the scope and purpose of the inspection at the entrance interview on May 16, 198 The findings of the inspection were discussed with licensee representatives during the course of the inspection and presented to licensee management at the May 20, 1988 exit interview (see paragraph 1 for attendees).

At no time ducing the inspection was written material provided to the licensee by the inspector. The licensee did not indicate that proprietary information was involved within the scope of this inspection.

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