ML20127E524
| ML20127E524 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 05/29/1985 |
| From: | Gray E, Wiggins J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20127E492 | List: |
| References | |
| 50-336-85-18, NUDOCS 8506240575 | |
| Download: ML20127E524 (5) | |
See also: IR 05000429/2005003
Text
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U.S. NUCLEAR REGULATORY COMMISSION
REGION I
Report No. 50-336/85-18
Docket No. 50-336
License No. DPR-65
Licensee: Northeast Nuclear Energy Company
P.O. Box 270
Hartford, Connecticut
Facility Name: Millstone Nuclear Power Station, Unit 2
Inspection At: Waterford, Connecticut
Inspection Conducted: April 29, - May 3, 1985
Inspectors:
E. H. Gray, LeacVReactor Engineer
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Approved by:
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y.pWiggins, pff rf, Materials
Uand ProcesW Section, DRS
Inspection Summary: Inspection during April 29 - May 3, 1985 (Report No.
50-336/85-18).
Areas Inspected: Routine, unannounced inspection by one region based inspec-
tor. The inspection included the areas of Inservice Inspection (ISI) program
activities including ultrasonic examination of piping and eddy current examina-
tion of steam generator tubes and steam generator sleeves. Work in progress
including sleeve installation on steam generator tubes and disassembly of the
service water pump "A" were observed. The control and status of the reactor
vessel material surveillance test coupons were reviewed. The inspection in-
cluded 35 hours4.050926e-4 days <br />0.00972 hours <br />5.787037e-5 weeks <br />1.33175e-5 months <br /> on site and an additional 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> at the regional office.
Results: No violations were identified.
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1.0 Persons Contacted
Northeast Nuclear Energy Company (NNECo)
J. Bergin, Engineer (Sleeving)
- T. Blanchard, ISI Coordinator - MS #2
S. Brinkman, Engineer (S.W. Pumps)
G. Closius, QC/QA Manager - MS#2
- J. Kelley, Superintendent, Millstone #2
- W. Romberg, Station Superintendent
- J. Smith, Engineering Supervisor
Northeast Utilities Service Company (NUSCO)
L. Baird, ISI Coordinator
H. Cote, Construction QC Supervisor
R. Fuller, UT, Level III
R. Michaud, Construction QC Manager
- Present at exit meeting on 5/3/85.
Combustion Engineering (CE)
C. Ashman, EC, Level III
ZETEC
R. Miranda, EC Data Analyst
2.0 Steam Generator (SG) Tube Eddy Current Examination
By the time of this inspection the eddy current (EC) steam generator tube
examinations were complete although EC data analysis was still in progress.
The inspector observed a portion of the eddy current analysis in progress
and reviewed the applicable procedure number STD-ISI-004, Revision 0.
Comparisons were made to the ASME Code Section XI, IWB 2413 and IWB2420
requirements and the intent of the NRC Regulatory Guide 1.83. The primary
defect identified is pitting on the tube secondary (outside) side at a
location within several inches above the upper surface of the tube sheet.
All of the accessible tubes in both steam generators were examined in this
area, to the first tube support plate, for pitting. Those with pits in ex-
cess of 39% through wall were scheduled for sleeving prior to continued
service.
The secondary side of the tubes in both steam generators were chemical
cleaned as an assist in removal of the secondary side copper bearing
- sludge. In the opinion of this inspector, this cleaning operation has
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enhanced the EC response from existing pits or made their detection easier
by removal of superfluous copper indications.
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In the sequence of eddy current data review, data is reviewed separately
by two groups. The results are then compared with differences being
reviewed and reevaluated. The licensee provided an independent third
party review of selected portions of the eddy current evaluation.
No violations were identified.
3.0 Steam Generator Tube Sleeving
The detection of pits greater than 39's throughwall just above the tube
sheet surface resulted in the decision to prepare those tubes for further
service by the insertion of sleeves and hard rolling them to the tube in-
side surface. The inspector reviewed the basic procedure for tube sheet
sleeving and portions of procedures applicable to specific steps in the
sleeving process. The training and mockup area for practice in both
robotic and manual sleeving was observed. Sleeving operations in progress
during the inspection including eddy current examinations to confirm that
sleeving was successfully completed were observed to determine the confor-
mance to applicable procedures, the level personnel training and control
over the sleeving process.
No violations were identified.
4.0 Ultrasonic Examination (UT) For Inservice Inspection (ISI)
The plant outage in progress during this inspection is the Final Examina-
tion period of the first ten year ISI interval. In continuation of in-
spection 50-336/84-17, the progress toward meeting the 10 year interval
ISI plant requirements was reviewed. The inspector noted the status of
completion of examinations, schedule to meet examinations yet required and
the documentation system in place to achieve the 10 year interval ISI
program plan.
In the UT area the inspector observed examination of welds MSA-CG-16 and
MSA-CG-14 as shown on drawing 25203-201-67. This UT was done in accor-
dance with procedures NU UT-1 Revision 4 and NU UT-3 Revision 2 as re-
viewed by the inspector. The UT observed and related activities were
compared to the requirements of the ASME Code Section V, Articles 4 and
5, the ASME Code Section XI and ASNT-TC-1A. The UT test blocks for speci-
fic UT data sheets were examined and data sheets, personnel qualifica-
tions, the procedure of indication evaluation, significance of data sheet
signoffs and the above mentioned UT procedures were reviewed.
No violations were identified.
5.0 Reactor Vessel Irradiation Material Surveillance Specimens
The plant Technical Specification paragraph 4.4.9.1(c) requires that:
"The reactor vessel material irradiation surveillance specimens
shall be removed and examined, to determine changes in material
properties, at the intervals shown in Table 4.4-3."
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Table 4.4.-3 requires capsule W-97 be removed and examined after 3.0 ef-
fective full power years (EFPY), with the next capsule (W104) scheduled
for removal after 10 EFPY.
The inspector determined that surveillance specimen removal and examina-
tion is under control of the plant ISI coordinator. The first surveil-
lance capsule (W-97) was removed from the Millstone Unit 2 reactor vessel
in August -1980 after 3.0 EFPY. Mechanical test specimens of base metal,
weld metal and weld heat affected zone provided for determination of ra-
diation induced changes of both tension and impact properties.
Temperature monitors, alloys with specific melting properties, indicated
the irradiation temperature to be between 536F and 558 F.
The inspector reviewed the report of evaluation of irradiated capsule
W-97 dated April 1982 by Combustion Engineering, Inc., and noted that
provision was made by the ISI coordinator for removal of capsule W-104 in
1988.
No violations were identified.
6.0 Service Water Intake Pump Columns - Independent Measurements
The original material of the service water intake pump columns was cast
iron. The cast iron was replaced with carbon steel on a temporary basis
until stainless steel could be obtained. The last replacement design as
installed in 1983 included type 316L flanges welded to type 316L plate
rolled and welded to form cylinders with welding per the ASME Code
Pumps "A" and "C" operate continuously during normal conditions, which
pump "B" is reserved for backup. During the 1985 outage scheduled
inspection found the internal column welding of pump "C" circumferential
velds had significant weld metal voids partially filled with a powder with
a chemistry of 24.4% Cr, 5.4% Ni, 60.9% Fe. Pump columns "B" and "A" were
removed and examined. Pump "B" had one area of one weld with a condition
similar to pump "C". Pump "A" columns had no visible areas with the
defective condition of pump "C".
The inspector saw a photograph of the defective condition of pump "C"
columns and examined visually the column section welds of pump "A", in-
cluding both the inside and outside surfaces of the longitudinal welds and
the six circumferential flange to pipe welds. The longitudinal welds were
noted to be nonmagnetic while the circumferential welds were slightly
magnetic as typical for austenitic stainless steel weld with at least 10%
ferrite. The Northeast Utilities Engineering / Materials Laboratory report
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dated March 29, 1985, by M. Galler and the purchase order for the columns I
were reviewed. The pump 'B" and "C" columns have been repaired, "C" by the
manufacturer and "B" at the site and examined both visually and ultra- !
sonically. The pump "A" column flange to pipe welds are scheduled for l
ultrasonic and formal visual examination. The pump manufacturer is con- l
ducting an analysis of the weld problem.
No violations were identified.
7.0 QA/QC Involvement in Areas Inspected
The inspector observed QA/QC personnel to be present and involved in
areas covered by this inspection. Procedures used in ultrasonic
examination, eddy current examination, and sleeving were noted to be
reviewed by QA as part of the plant operating review committee activity
in advance of performance of the actual work activities. During
sleeving and eddy current sleeved tube area examination, QC personnel
were present and actively involved in documentation of work steps and
sequences. Level III nondestructive examination personnel were involved
in both ultrasonic and eddy current examination activity.
No violations were identified.
8. Exit Meeting
The inspector met with licensee representatives, listed in paragraph 1,
at the conclusion of the inspection to summarize the scope and findings
of the inspection. At no time during this inspection was written
material provided to the licm see by the inspector.
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