ML20128J039
| ML20128J039 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 09/30/1996 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20128H996 | List: |
| References | |
| 50-413-96-12, 50-414-96-12, NUDOCS 9610100163 | |
| Download: ML20128J039 (21) | |
See also: IR 05000413/1996012
Text
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U.S. NUCLEAR REGULATORY COMMISSION
REGION II
Docket Nos: 50-413. 50-414
Report Nos.: 50-413/96-12, 50-414/96-12
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Licensee: Duke Power Company l
Facility: Catawba Nuclear Station. Units 1 and 2
Location: 422 South Church Street
Charlotte. NC 28242
Dates: August 4 - August 31. 1996
Inspectors: P. Balmain. Resident Inspector
J. Coley, Reactor Inspector ,
N. Economos. Reactor Inspector i
Approved by: L. D. Wert. Acting Chief. Projects Branch 1
Division of Reactor Projects
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ENCLOSURE 2
9610100163
DR 960930
ADOCK 05000413
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EXECUTIVE SUMMARY
Catawba Nuclear Station. Units 1 & 2
NRC Inspection Report 50-413/96-12. 50-414/96-12
This integrated inspection included aspects of Steam Generator Replacement
Project activities in the area of engineering. The report covers a 4-week
period of announced inspection performed by resident and regional reactor
inspectors.
Enaineerina
- Two violations were identified regarding secondary system welding. The
first violation with two examples was identified for failure to follow
procedures concerning weld preheat and weld process control packages.
The second violation was identified concerning inadecuate welder
training . The violations and other observations incicated sipificant
weaknesses in the welding program used to fabricate secondary system
welds. The licensee initiated corrective measures to address several
of the identified weaknesses. but it appears that additional steps need
to be taken to address the significant number of welding program
problems identified (Section E1.2 and E1.3).
- The preparation. assembly, fabrication and testing of Reactor Coolant
System welds without encountering significant problems is considered a
strength in engineering (Section E1.1)
- A violation was identified for inadequate design control verification
measures. The NRC identified that the as-built configuration of screens
utilized in containment crane wall pipe sleeves and floor drains did not
implement design requirements for minimizing sump screen loading due to
paint chips or blanket insulation material (Section E8).
- The licensee's foreign object search and retrieval activities were
extensive. The quantity of foreign material retrieved from primary and
secondary system areas was minimal. Evaluations performed for objects
known to be left in the steam generators determined that the objects
would not lodge in the tube bundles and cause fretting problems (Section
E1.4).
ENCLOSURE 2
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I Reoort Details
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Summary of Plant Status
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Unit 1 began the period defueled for the end-of-cycle 9 refueling and steam
generator replacement outage. The unit remained in this condition with steam
generator replacement activities in process for the duration of the inspection
period.
Review of UFSAR Commitments
A recent discovery of a licensee operating their facility in a manner contrary
to the Updated Final Safety Analysis Re) ort (UFSAR) description highlighted
the need for a special focused review tlat compares plant 3ractices,
procedures and/or parameters to the UFSAR descriptions. W1ile performing the
inspections discussed in this report, the inspectors reviewed tie applicable
portions of the UFSAR that related to the areas inspected. The inspectors
verified that the UFSAR wording was consistent with the observed plant
practices, procedures and/or parameters. Identified deficiencies involving
containment sump screens are addressed in Section E8.
I. Enaineerina
El Conduct of Engineering
El.1 Steam Generator Reolacement (50001)
a. Insoection Scooe
Evaluation by direct observation and document review, of the adequacy of
the licensee's Steam Generator Replacement Program (SGRP), with regard
to: welding of piping in primary and secondary systems (i.e. , reactor
coolant, main steam, main feedwater and others), postweld heat ;
treatment, review of radiographs of in-process and completed welds, and
ultrasonic examination of completed welds per ASME Section XI to verify
compliance with preservice inspection requirements.
b. Observations and Findinos
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Weldina Reactor Coolant Pioina to Reolacement Steam Generators
Reactor coolant pipe welds joining hot and cold leg piping were
fabricated using a narrow groove joint design and the remote control
machine gas-tungsten arc welding process. Welding of field joints was
performed by Framatome Technologies who was contracted by the licensee
to provide equipment and personnel for this purpose. Details relative
to weld procedure qualification and welder training in preparation for
this activity were discussed in NRC Inspection Reports 50-369,370/94-05,
50-413.414/96-07 and 50-413.414/96-11.
ENCLOSURE 2
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Welding related activities observed during this inspection period
included cleanliness and fitup, in process welding. repairs, cleanup and ,
grinding. visual inspection of completed welds, and review of process
control documents. Within these areas. the following was noted by the
inspector.
- SG "C" Hot and Cold Lea Weld Root Reoair
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Weld joint axial mismatch which exceeded specification requirements
required the use of ceramic backing material to facilitate welding the
root over a limited section of the joint. When the weld joint was
partially completed. the weld surface in contact with the ceramic
material was ground and examined with liquid penetrant for evidence of
surface indications. The inspector witnessed the test and noted that it
produced evidence of linear and rounded indications in the root surface
area associated with the backing material. These indications had
, minimal depth and were removed by light grinding. A followup inspection
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showed the indications had been removed and the root surface in both
joints was satisfactory.
Thickness of Existina Elbows Below Code Allowable
Thickness measurements of the existing cast elbows near the weld joint
indicated that material thickness were either at or close to the code
allowable minimum (2.42 inches). This condition was attributed to the
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existing casting thickness irregularities and the machining operation
for 3 reparation of the initial weld joints. Machining and the machining
i of t1e counterbore for concentricity and for the tight fitup tolerance
3 required for the narrow gap weld joint design, reduced wall thickness
dimensions to below code minimum. To correct this condition. Framatome
added a sufficient amount of weld metal to the OD surface, adjacent to
the weld: thus restoring material thickness to acceptable levels. By
, review of the Weld Process Control Sheets (WPCS) and associated
Jackages the inspector ascertained that instructions for this activity
1ad been documented on Form CWP-1B. Alteration / Repair Process Control.
These instructions included the weld procedure to be used, approximate
weld metal thickness to be deposited, weld metal surface finish,
geometry, and testing to be performed. Within these areas the inspector
found the weld buildup, workmanshi) and finish satisfactory. However,
the inspector did not agree with t1e licensee's decision to document the
weld metal buildup on the material as a weld joint repair. The
inspector's position was that while the added filler metal was fused to
the weld joint, its sole purpose was to restore material thickness and
not to repair a defect in the weld joint as the documentation on the
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WPCS would suggest. The metal addition was identified as Repair 1 for
- each of the eight weld joints. As such, the inspector stated that this
activity should have been documented on a separate WPCS and given a
unique weld number for future reference. In closing, the licensee's
cognizant engineer agreed with the inspector's position and issued a
ENCLOSURE 2
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cover sheet to explain the reason for the repair, the applicable
i controlling code, and the welding process used. Each cover sheet was
attached to the weld package of each of the eight reactor coolant welds.
Review of Stress Analysis Calculations
The weld metal buildup on the crossover and hot legs was performed in
accordance with the ASME code requirement NB-4214 and NB-4130. However,
as an added design conservatism, the inspector requested that the
licensee review the original stress calculation (CNC-1206.02-70-0093) to
determine whether the weld metal buildup and the apparent change in weld
contour could have changed the validity of the above-mentioned stress
calculation. The inspector discussed this concern with the staff at NRC
Headquarters who agreed with the inspector's request for the licensee's
review. On September 17. 1996, the licensee provided the inspectar the
results of the review and evaluation which showed the stress indices at
those locations were well within the limits of the initial calculation.
Review of Radicaraohs - Comoleted Reactor Coolant Welds ,
Completed reactor coo' ant SG hot leg and crossover leg welds were i
radiographed to satisfy ASME Code Section III requirements. The welds !
were shot in accordance with the licensee's Radiographic Procedure NDE-
10A, Rev. 19. Welds selected for this review were as follows:
Weld
INC22-2 B Hot Leg 2.57"x31" No Rejectable
Indication (NRI)
1NC22-3 B Crossover 2.57"x31" NRI
INC23-2 D Hot Leg 2.57"x31" NRI l
1NC23-3 D Crossover 2.57"x31" NRI !
1NC24-2 A Hot Leg 2.57"x31" NRI
INC24-3 A Crossover 2.57"x31" NRI ,
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l From this review. the inspector noted that film and radiographic quality I
met the required code minimum standards; however, in several instances,
the inspector observed that film placement was such that it barely
covered the area of interest. Also, the inspector observed that many of
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the radiographs exhibited numerous artifacts, including roller marks. '
l This observation was discussed with cognizant NDE personnel and
management. They acknowledged that the condition existed and that it
was due in part to a problem in the processor which they were determined
to correct. This condition was subsequently corrected as evidenced by
the quality of radiographs for the CF and SM welds.
Preservice Insoection of Reactor Coolant Welds
As required by ASME Code Section XI. reactor coolant system weldments
must undergo volumetric / ultrasonic examination before the plant returns
ENCLOSURE 2
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to power. Procedures used for this purpose must meet the subject code's
minimum requirements. As such, the licensee utilized ultrasonic
examination procedure NDE-610. Rev. 3. which references ASME Code
section XI. 1989 Edition. The examination covered the inner 1/3
thickness of the weldment and 1/4" of the adjacent base metal on each
side of the weld subjec: to accessibility. Because at the time of this
inspection all replacement reactor coolant loop welds had been examined,
the inspector reviewed examination records for adequacy, accuracy.
completeness and compliance with the subject code. Through this review,
the inspector ascertained that each weldment was examined with refracted
l 45 and 60 degree transducers. Welds were scanned in the axial and
l circumferential directions with the 45 degree transducer and only in the
- axial direction, from the safe-end side, with the 60 degree transducer.
Weldments for which records were reviewed were 1NC22-2 and -3. 1NC23-2
and -3. 1NC24-2 and -3 and 1NC25-2 and -3. Out of these eight welds,
only 1NC25-2 exhibited geometric reflectors in the root. This weld was
in the hot leg of the "C" loop where some mismatch was encountered
during the fitup and a ceramic backing was used to facilitate root
closure. Therefore, the indication was not totally unexpected. Other
records associated with these examinations that were reviewed included
certifications for instruments, transducers. calibration blocks, and
personnel.
c. Conclusion
The preparation, assembly fabrication and testing of reactor coolant
system welds without encountering problems of any significance is
considered as a strength in engineering. This achievement can be
attributed to the 3 reparation and planning by the licensee's lead
engineers and to tie intense training of the contractor's welding
personnel to achieve the necessary proficiency for performing their
assigned tasks. The licensee's efforts towards attaining this objective
was a significant SGRP group strength.
El.2 Fabrication and Testino of Main Feedwater and Main Steam Welds (50001)
a. Insoection Scooe
This inspection effort was a followup to that documented in NRC
Inspection Report No. 50-413.414/96-07. which covered Main Feedwater
welds that were welded in the licensee's fabrication shop.
The present inspection effort covers welds fabricated in the field
(inside Unit 1 containment) and includes welding, process control,
thermal treatment and testing,
b. Observation and Findinas
The inspector observed various as)ects of field weld fabrication in
several pipe systems, including t1e main steam and main feedwater
ENCLOSURE 2
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systems. Welding activities and practices were observed to verify that
the new welds were being fabricated and tested in accordance with the
l applicable code and regulatory requirements. This provided a reasonable
assurance that replacement components and the plant would operate in a
safe manner. To perform this task, the inspector selected for
observation, welds at various stages of fabrication (i .e. . fitup,
preheat, root closure, welding-out the joint, and postweld heat
treatment). Welds selected for this task were as follows:
Main Steam (SM)
SG A ISM 34-38 Outlet Nozzle to Elbow
ISM 34-37 Riser
1SM29-35 Riser
SG B 1SM39-35 Outlet Nozzle to Elbow
ISM 29-35 Riser
SG A 1CF038-01 Nozzle to Elbow
1CF038-10 Pipe to Elbow
1CF038-14 Pipe to Reducer
1CF002-04 Pipe to Pipe
1CF002-13 Pipe to Pipe
SG B 1CF039-01 Nozzle to Elbow
1CF039-10 Verticle Pipe to Elbow
1CF037-04 Pipe to Pipe
1CF039-13 Pipe to Pipe
SG Blowdown Recycle (BB)
SG Wet Lav-uo Recire. (BW)
Auxiliary Feedwater (CA)
Field welds were fabricated utilizing welding procedures from the
licensee's Welding Manual. These procedures were qualified to meet the
recuirements of ASME Code Sections IX. XI and III 1989. Pipe reroute
anc reassembly for the subject systems were addressed in Final Scope
Documents CN-19429. CF Piping Reroute. and CN-19510. Removal and
Installation of SM Lines.
ENCLOSURE 2
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i Fabrication of field welds was controlled by the applicable Process
j Specification and the Field Weld Data Sheet (FWDS) both of which
! contained process variables of the qualified welding procedure. Process
Control Sheet (CWP-1A) from the Maintenance Welding Manual.Section I,
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Rev.1. provided a historical fabrication record of a given weld and was
used to identify fabrication milestones (e.g., hold points. 0A/0C sign-
offs. Authorized Nuclear Inspector hold Joints, preheat and other
j 3ertinent information relative to the fa)rication of a given weld).
l 41 thin these areas. the inspector made the following observations.
- Keeoina Weld Documentation Packaae At The Job Site
S)ecification L-100. Welding Program, paragraph 4.3.3 states in part
j t1at a copy of the FWDS shall be available in the work area of t1at
- particular weld. Also Nuclear System Directive 704, Rev. 4. paragraph
- 704.6 states in part that a copy of the procedure shall be in the
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possession of the performer (s) at the job site. Contrary to this
requirement, on August 5-9, 1996, the inspector observed that weld
documentation packages were not being kept at the location where welds
were being fabricated.
. Failure to have these records readily available at the job site
i precludes welders and QA/0C inspectors from reviewing information ,
i essential to weld fabrication. to signing off on OC hold points, and to I
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document random inspections during fabrication. This failure to keep
< weld data packages at the job site as required by procedure is
- considered a violation of 10 CFR 50. Appendix B. Criterion V. and will
be identified as VIO 50-413/96-12-01. Failure To Follow Procedures.
Preheatina Welds
, The Licensee's Process Specification L-900. Rev. 3 provides guidelines
! for preheating, maintaining interpass temperatures and postweld heat
i treating of production welds. This s)ecification states in part that
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the entire joint to be welded, shall 3e preheated to the temperature
saecified on the FWDS...and shall be maintained throughout welding of
j t1e applicable joint. Paragraph 5.2.2 of the subject document requires
! that resistance heating elements (blankets), used for preheat and
- interpass temperature control operations, will be placed as closely as
i )ractical to the weld preparation on each side of the joint. Also.
- Metal Arc Welding, paragraphs 9.2 and 7.2 respectively, require that
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preheat be maintained throughout the welding of the applicable joints.
- This requirement is further supported by Regulatory Guide 1.50. May
i 1973. Control of Preheat Temperature for Welding of Low-Alloy Steel
J Section C.2 and C.3 which states in part that for production welds, the
i preheat temperature should be maintained until a post-weld heat
i treatment has been performed and, that production welds should be
j monitored to verify that the limits on preheat and interpass
i temperatures are maintained.
! ENCLOSURE 2
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By observation and through discussions with craft. OC inspectors, and :
craft supervisors, the inspector noted that the use of a flame torch was )
the preferred method for preheating production welds to the required ,
temperature. Flame torches were used for preheating prior to tacking i
and prior to welding the weld joint. A flame torch was used to reach !
and maintain minimum
one additional pass. preheat
From thattemperatures during
point on, minimum root temperatures
preheat closure and for
were maintained from heat generated by the welding process during
welding. The inspector observed that preheat was not being maintained
on several partially completed joints where welding had been stopped.
In these instances. the weld joint temperature had returned to
room / ambient temperatures.
Also by observation. the inspector noted that the above-mentioned
preheat requirements were not being followed while welding weld CFO
40-10. In this case only one resistance heating blanket was used for
maintaining preheat instead of one on either side of the joint as
required by the specification. These findings of failure to follow l
procedure are considered an additional example of VIO 50-413.414/96-12-
01 identified earlier in this section.
In discussing preheat practices and concerns with the licensee's !
cognizant engineer, the inspector stated that although use of a flame l
torch for this purpose was not a prohibited practice, it was not the
preferred method for preheating low-alloy materials e.g. , Cr-Mo piping
and Main Steam Lines in nuclear power plants and particularly on S/G
replacement projects. Also, the inspector stated that because flame
torch heating of welds is heavily dependent on the skill of the craft.
there is little or no assurance that all the requirements specified by
the specification have been followed. To underscore this concern, the
inspector ascertained through discussions with craft, that they had no l
clear understanding or formal instruction on the specified area around
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the weld joint that had to be preheated and/or the importance of
maintaining minimum preheat temperature throughout weld fabrication.
During this time. the inspector also noted that temperature indicating
crayons (temp sticks) were not in the possession of all welders
fabricating welds. This was noted when the inspector asked welders for
use of their temp sticks to check preheat and interpass temperatures,
but had to wait until one was borrowed from another crew before
proceeding with the test. This further heightened the concern over the
adequacy of preheat temperature control.
On August 8 and 9,1996, the inspector had a preliminary exit interview
with the licensee's site management and oiscussed in detail the concerns
and findings described above. The licensee reacted in a positive manner
ENCLOSURE 2
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to the inspector's concerns and findings and took the following
corrective actions:
. Stopped work to assess the situation and to discuss welding
practices with craft and supervision.
. Developed preheat guidelines for making tacks and welds. These
guidelines were issued on August 11, 1996.
. Developed maintenance procedure MP/0/A/7650/147 to describe
preheat requirements. Copies of this procedure were placed in all
applicable process control packages. This procedure contains an
attachment for documenting preheat for fabricating tack welds and
welding out of weldments.
. Provided for weld process control packages to be at weld
locations.
. Provided for increased management oversight to ensure compliance
with all welding requirements.
. Provided for all welds requiring preheat to be wrapped using
resistance heaters except where engineering granted an exemption.
. Increased frequency of OC random inspections with emphasis on
preheat /interpass temperature monitoring and for documentation in
the forms provided
. Provided training for line management and craft on welding program
changes being implemented.
. Conducted Laboratory Tests for tack welds and production welds
using a flame torch to determine length of time to reach minimum
preheat temperatures. Tests were performed on Chromium-Molybdenum
(Cr-Mo) material from 2"-6" thick.
. Issued PIP 1-C96-2082 and ]erformed an insight investigation on
main steam weld 1SM34-38 w1en a raridom inspection disclosed that
the 200 degree Fahrenheit minimum preheat tem)erature had not been
maintained over the entire circumference of t1e joint. Preheat
was maintained on opposite sides where welding was in progress.
- Secured the services of an independent welding consultant to
assess the SGRP and plant secondary side weld program and
practices with emphasis on preheat application.
. Performed overall Weld Program review including other critical
elements of the welding process and made appropriate
recommendations for strengthening the Duke Power Welding Program.
ENCLOSURE 2
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Replacement of the SGs required the removal and subsequent
4 reinstallation of main steam piping, immediately off the SGs. As such,
the piping was cut at the SG nozzle and near the bottom of the second
elbow. The design of the new SGs required that the existing CF line be
cut and rerouted to accommodate the new location of the CF nozzle on the
SGs. The replacement piping was made of Chromium-Molybdenum (Cr-Mo),
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low-alloy steel . This material was selected for its demonstrated
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resistance to erosion / corrosion attack. This material requires that
- welds be preheated and postweld heat treated following fabrication.
Field welds in the SM and CF systems were fabricated using gas tungsten
Arc (TIG) and shielded metal arc welding procedures from the Duke
Welding Manual. By record review the inspector ascertained that both i
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welding procedures and welders were qualified in accordance with ASME
Code Section IX requirements. Welders and their supervisors assigned to
this project were from the licensee's Electric System Support (ESS)
Department.
Between August 5-9, 1996, the inspector observed welding activities in
both systems and the findings were discussed earlier in this section of
this report. As a result of these observations, through reviews of
radiographs of in process and completed welds, and from discussions with
technical personnel the inspector became concerned over the relatively
high rate of rejections in these two systems and particularly in the BB ;
system where the nozzles were buttered with inconel material. Weld !
rejections, when they occurred, were for the most part associated with
the root and were identified as incomplete penetration and/or incomplete
fusion. Slag, porosity, and crack indications were also observed in l
weld locations. These rejectable indications were observed in various
degrees in all of the three systems inspected and more predominately in l
the BB system nozzle welds where repair rates ranged from 2 to 11 )
repairs per nozzle weld joint, Rejections in the CF and SM system were
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not as high, but still higher than would be expected based on the ,
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inspector's past experience with similar SGRPs where the same manual
processes were utilized. For example, out of the eight weld joints that
were fabricated in the SM system. five were rejected by radiography and
required weld repairs. One of these welds (No. ISM 29-36, outlet nozzle
to elbow weld on SG A) required seven repairs before it was accepted by
radiography. The inspector requested, and the licensee agreed, to
stress relieve /postweld heat treat this joint as a precautionary measure
to guard against the residual stresses which may have been built up by
the multiple weld repairs. In the CF system, weld rejections were
similarly high, as approximately 50% to 55% of the field welds required
anywhere from one to five weld repairs before being accepted by
radiography.
Through observations, discussions with craft and field supervisors and
by reviews of the licensee's assessment and other SGRP documents. the
ENCLOSURE 2
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following was ascertained by the inspector.
Trainina of Welders
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CN-19420. CF Piping Reroute. Section 10.6.2 Materials Section and
Fabrication, states in part that Duke complies with Regulatory Guide
1.71 Welding Qualification for areas of Limited Accessibility. However. l
Duke took exception to the regulatory position for welders to be tested
for proficiency under simulated access conditions such as those that
would be encountered when fabricating production / field welds. Duke's l
approach was to use only highly skilled personnel as a means of assuring
acceptable welds. As such, welders used for this project came from
Duke's ESS group for their familiarity and expertise in welding these
materials.
Through discussions with craft, supervisors and SGRP management the
inspector ascertained that welders were brought onsite immediately l
before work was to begin. They were provided little or no formal
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training or indoctrination on the requirements of the welding 3rogram
and were given no mock-up training to achieve proficiency in t1e
production of radiograph quality welds under field conditions.
Therefore the inspector believes that the licensee's decision to rely
heavily on the welder's past experience with welding these materials
instead of spending the time and resources to adequately train them was
a major contributor to the poor welding performance demonstrated during
this outage.
Failure to provide adequate indoctrination and training of personnel
performing activities affecting quality to assure that suitable
proficiency was achieved and maintained is considered a violation of 10
CFR 50. Appendix B. Criterion II Quality Assurance Program and will be
identified as VIO 50-413/96-12-02. Failure to Adequately Train Welders
To Perform Their Assigned Tasks.
Postweld Heat Treatment CF Welds
Postweld heat treatment (PWHT) of completed CF welds was performed to
satisfy applicable code requirements. This activity was controlled by
Duke's Welding Manual Process Specification L-900. This specification
provides the guidelines for thermal treatment of welds and uses data
sheets for specific ap)lications. Data sheets used for PWHT of CF pipe
and nozzle welds were _-924. Rev. 2 and L-923. Rev. 1. respectively.
The inspector reviewed the specification and the subject PWHT data
sheets for technical content, adequacy, and compliance with applicable
code requirements. Following is a list of welds that underwent PWHT and
the inspector observed the activity in progress or reviewed heat treat
charts and associated records.
ENCLOSURE 2
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Weld Descriotion Parameters
CF037-3 and -4 Pipe to Elbow 1hr @ 1150 F
CF038-1 Nozzle to Pipe Ihr @ 1135 F
CF038-10 Pipe to Elbow 1hr @ 1180 F
CF038-14 Pipe to Reducer Ihr @ 1180 F
CF039-1 Nozzle to Elbow 1hr @ 1135 F ,
CF039-10 Pipe to Pipe Ihr @ 1150 F
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CF039-14 Pipe to Pipe Ihr @ 1150 F
- 1SM29-36 Nozzle to Pipe 1 1/2hr @l150 F
- This weld did not require PWHT but was done in response to the
inspector's concern over the numerous re) airs and associated residual
stresses which may have accumulated in t1e process. Through
observations and reviews the inspector ascertained that PWHT was
consistent with code and specification requirements and that
documentation of the activity was satisfactory.
Preservice Examination of CF and SM Welds
SM welds were radiographed to satisfy ASME Code Section XI requirements
for a volumetric examination prior to the plant returning to power l
operations. The procedure used and ap)licable code was discussed
earlier in this report. A review of tie radiographs for the eight new
welds was performed. This review indicated that the radiographs met
minimum code requirements and that the welds were free of rejectable '
indications.
CF welds were ultrasonically examined and the results evaluated.
Procedures used included NDE-640. Rev. 1. with applicable code
requirements used to detect planar or laminar flaws in the base metal
while NDE-600. Rev. 7. was used to detect flaws in the weld metal. The
latter provides for axial and circumferencial scanning of the weld with
shear and or long wave transducers.
Because ultrasonic examination of the subject welds was complete at the
time of this ins)ection, the inspector reviewed records of the
examinations. T1ese records were reviewed for completeness, accuracy,
and adequacy of evaluations for indications. Certifications of
equipment. materials and personnel were reviewed at this time. This
work effort was performed for the following welds:
Weld Nc. Results
ICF 39-2 Root condition evaluated as acceptable.
documented for future reference.
1CF 39-12 and -13 No recordable indications (NRI).
1CF 40-11 and -13 NRI.
ENCLOSURE 2
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1CF 41-2 NRI.
1CF 41-15 Root condition evaluated as acceptable, ;
documented for future reference.
1(,F 36-5 Geometric indications due to counterbore !
configuration.
1CF 36-2 Geometric indications due to counterbore
configuration. l
1CF 37-5 Geometric indications due to counterbore
configuration.
c. Conclusion:
The welding program used to fabricate plant secondary side welds showed
significant weaknesses. These were demonstrated by: the failure to 7
adequately train welders to produce radiograph quality welds in the
restricted environment of the containment building; the use of flame :
torches for preheating safety-related low-alloy pipe welds and failure
to comply with specification requirements: failure to provide process !
control information at the work stations; failure to establish minimum
standards for random QC surveillances and to enforce its documentation:
and failure of line supervision to provide adequate oversight and
guidance in identifying and resolving weld fabrication problems and poor
welding practices.
The licensee initiated corrective measures to address several of the
identified weaknesses, but it appears that additional steps need to be
taken to address the significant number of problems identified.
E1.3 Review of Radicarachic Film for Steaq ffnerator Reolacement Pioina Welds
a. Insoection Scoce (50001)
Radiographic film for steam generator replacement piping field welds
were reviewed by the inspectors. This review was conducted to verify
that the radiographic process, including the acceptability of welds, met
ASME Code requirements. In addition, the inspectors reviewed and
assessed the high weld reject level experienced by manual welders on the
steam generator replacement project. In order to fully assess the
welding problem, radiographic film of acceptable and rejectable welds
were reviewed. The rejectable radiographs were reviewed to determine i
the location in the weld where the defects were occurring, what type of
welding defect conditions were involved, and if corrective measures
taken by the licensee to improve welding proficiency were effective.
ENCLOSURE 2
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b. Observations and Findinas
Acceptable radiographs for the reactor coolant (NC), main feedwater
(CF). steam generator blowdown (BB). steam generator wet layup (BW) and
mainsteam (SM) field welded pipe welds delineated below were reviewed.
The licensee's code implementing 3rocedure for this examination was NDE
10 Revision 19. General Radiograplic Procedure, which referenced ASME
Code Sections III. V and XI. 1989 Edition. The inspector reviewed the
radiographs to verify proper penetrameter type, size, placement,
sensitivity, film density, proper film identification, weld coverage, j
and evaluation and disposition of weld discontinuities.
Weld No. Weld No, )
l
NC23-2 CF37-04
NC22-3 CF3-14
CF38-10 BB129-04
CF39-10 BW16-02
CF38-14 CF38-01 ;
CF2-15 CF39-01 1
CF36-14 SM34-38 i
CF40-14
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NC24-2
CF37-16 BW19-34
CF36-15
4
In addition to the above acceptable film, the following rejectable film
packages for the welds delineated below were reviewed:
Weld No. Weld No.
'
BB128-8 CF41-10
BB128-7 CF37-15
BB127-4 CF2-13
BW16-1 BB134-4
CF40-10 BB132-4
CF39-14 SM29-36
CF40-14 CF34-1
CF2-4 BW19-1
Through the review of the film for the welds listed above, the inspector
concluded that film accepted by the licensee's NDE staff were
acceptable, and the film rejected by this staff were rejectable. The
inspector's review also determined that almost all weld rejects, whether
initial welds or repairs, were occurring in the weld root area. The
deficient weld conditions were generally the result of lack of weld
fusion or lack of a weld Jenetration. The licensee had determined and
the inspector concurred tlat the inconsistency in welding an acceptable
weld root pass was indicative of lack of welding proficiency caused by
inactivity in the area of welding. The licensee was giving welders
additional training on mockups to improve this trend before starting the
ENCLOSURE 2
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auxiliary feedwater system welding. In addition. manual welding
equipment with enhanced welding features were being sent to the Catawba
site. Several issues were raised by the inspector and addressed by the
licensee during the week of the inspection. They consisted of the l
following: ;
- Due to multiple repairs which extended to the weld root for the 3-
inch diameter BB and BW nozzles to pipe welds, the inspectors
questioned whether sufficient inconel buttering remained on the
nozzle end preps. To address this issue the licensee provided the
inspector with appro)riate drawings for the NC, BB, and BW systems
which depicted 1-inc1 of inconel weld butter applied on each
nozzle end prep. In addition, the licensee had engineers verify
that sufficient inconel butter could be seen remaining on each
nozzle.
- Radiographic examination reports used by the licensee had a column
labeled " dimensions" for film interpreters to record the size of
discrepant indications. The inspectors noted one case where an
interpreter had not done so. Although, this is not a Code
requirement it aids a second reviewer in determining whether the
interpreter based his acceptance of an indication on rounded
indication or an elongated indication criteria. This difference
becomes important when indications approach their minimum or
maximum allowable dimensions in a classification category. This
item was discussed with the cognizant supervisor who informed the j
film interpreters to record the dimensions of all relevant i
indications.
. The inspector held discussions with cognizant engineers to
determine whether the radiographic results were considered when
assigning welders to weld joints that were ex)eriencing multiple
repairs. The engineers stated that this had Jeen taken into
consideration.
c. Conclusion
Deficient welding on the steam generator replacement piping was
controlled by the licensee through effective and conservative
radiographic film review. The high weld reject rate was caused by the
lack of welder proficiency in making manual field weld root passes
particularly when using inconel weld filler material. The licensee was
taking appropriate corrective actions for this problem.
El.4 Foreian Obiect Search and Retrieval Activities (50001)
a. Insoection Scooe (50001)
During this inspection period the inspector reviewed the results of the
licensee's investigation of a loss of Foreign Material Exclusion (FME)
ENCLOSURE 2
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15
controls at the steam generator (SG) fabrication facility that resulted
, in three weld wires being left in one of the SG moisture separators.
The inspector reviewed and observed search and retrieval activities for
several unaccounted for objects and also reviewed the results of Foreign
Object Search and Retrieval (FOSAR) inspections performed in the SG
secondary areas, reactor coolant system hot and crossover legs, and the
reactor vessel.
b. Observations and Findinas
The licensee's investigation concluded that the three weld wires found
in the 1A SG were left in the SG at the Babcock & Wilcox International
(BWI) facility following FOSAR inspections performed during
manufacturing of the SG (PIP 1-C96-2099). The licensee performed
extensive FOSAR inspections of the up)er tube bundle areas and the top
of the tube sheets in all the SGs. T1e inspector witnessed portions of ,
these inspections. No additional weld wires were identified during the i
inspections. Several items were retrieved during the inspections
including a small quantity of weld slag. wire and tape. Two items were
known to be left in the 1B SG, a screwdriver tip and a piece of weld
slag. BWI concluded that due to their small size they would not cause
fretting problems in the bundle and would likely deposit in a low
velocity area or exit through the blowdown system.
Foreign material exclusion plugs used in the Reactor Coolant System
(RCS) hot legs and crossover legs were not effective in preventing
debris from entering the RCS piping. Sponge material used in the pipe
end decon process was found in these areas after the alugs were removed.
The licensee performed FOSAR inspections of each of t1e hot and
crossover legs. The inspector reviewed video tapes of the C SG F0SAR
and verified that the licensee was effective in removing sponge debris
from the RCS piping. The inspector verified by reviewing work order
(WO) documentation that quality control (OC) inspections performed
following the F0SARs found cleanliness conditions in all of the RCS
piping to be acceptable and all of the sponge material was removed (WO 95098510.20.21.22 and PIP 1-C96-2257).
c. Conclusions
The licensee's foreign object search and retrieval activities were
extensive. The quantity of foreign material retrieved from primary and i
secondary system areas was minimal. Evaluations performed for objects i
known to be left in the steam generators determined that the objects '
would not lodge in the tube bundles and cause fretting problems. ;
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ENCLOSURE 2
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E8 Hiscellaneous Engineering Issues (92903)
(Closed) URI 50-413.414/96-11-01: As Built Discrepancies Could Allow 3
Debris Transport to Containment Sump Screens. This item was opened ;
pending com)letion of the licensee's evaluation of several discrepancies
identified )y the inspector during a walkdown of Unit 1 containment sump
areas. The discrepancies included: (1) Floor drains that were not
covered with a screen that had a finer mesh than the sump screen as i
required by design calculation (CNC-1223.11-00-0005, Justification for
Using Flexible Blanket Insulation Inside Containment) and (2)
containment crane wall pipe sleeves that were not covered with screens
as specified in FSAR section 6.3.4.1. ECCS Performance Tests.
Subsequent to the initial identification of these problems the licensee
also recognized that four additional floor drains that did not have any
form of filter or screen. The discrepancies were not an immediate
concern for Unit 1 since the unit was defueled.
The licensee took actions to plug the Unit 2 crane wall pipe sleeves and
determined that the operability of Unit 2 recirculation sump would not
be adversely impacted by the potential transport of insulation to the
sump screen. The inspector reviewed the licensee's operability
evaluation (PIP 2-C96-1958), which was initiated following the
inspector's identification of this issue. The inspector agreed that
the impact on the Unit 2 sump operation would be minimal because
quantity of installed insulation was relatively small, the transport
path to the open pipe sleeves and floor drains was tortuous, and the
1/4-inch installed floor drain screens would limit insulation debris
that could reach the sump screen. The licensee determined that the
cause of using 1/4-inch floor drain screens instead of 1/8-inch screens
was because of an incomplete use of reference material during the
preparation of a modification which changed the size of the floor drain
screens. The licensee also determined that design basis information
relative to the size of the recirculation sump screens was incorrect and
confusing.
Based on this review, the inspector concluded that the licensee's design
control measures were not adequate to ensure the as-built configuration
of screens utilized in containment crane wall pipe sleeves and floor I
drains implemented design requirements for minimizing sump screen l
loading due to paint chips or blanket insulation material. The !
protection of sump screens from debris is significant since clogging of !
sump screens can potentially result in a reduction or loss of reactor !
core cooling flow following a loss of coolant accident. This issue is a l
violation of 10 CFR 50. Appendix B. Criterion III Design Control, and
will be identified as VIO 50-413,414/96-12-03. Inadequate Design !
Controls For Ensuring Containment Crane Wall And Floor Drain Screens
Implemented Design Requirements.
ENCLOSURE 2
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II. Manaaement Meetinas
X1 Exit Meeting Summary i
l
l The inspectors 3 resented the inspection results to members of licensee l
management at t1e conclusion of the inspection on September 5.1996. The l
licensee acknowledged the findings presented. No proprietary information was l
identi fied. i
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ENCLOSURE 2
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- PARTIAL LIST OF PERSONS CONTACTED
Licensee
Benoit. R., SGRP Engineer
Bowers. B.. Manager. ESS. SGRP
'
Cheezem. C. , Manager. NDE Diversified Services
- Connell K., Licensing and Procurement Manager. SGRP
i Crump. J. SGRP Engineer
.
Forbes J., Engineering Manager
i Hallman G., Project Director. SGRP
. Kent. G., SGRP Engineer
! Kitlan. M.. Manager. Regulatory Compliance
i McCollum. W., Catawba Site Vice-President
- Medlin. R.. ESS Customer Support Manager
l Nicholson. K., Compliance Specialist
- Patrick. M., Manager. Safety Assurance
f Peterson, G., Station Manager
Pitser. K., SGRP Engineer
Sharpe. R., SGRP Licensing
Sills. S., SGRP Site Manager
Stout. D. , Engineering Supervisor
Tower. D., Compliance Engineer
Van Malssen. S., ESS
ENCLOSURE 2
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INSPECTION PROCEDURES USED
IP 50001: Steam Generator Replacement Inspection
i
j IP 92903: Followup - Engineering
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4 ITEMS, OPENED, CLOSED, AND DISCUSSED 1
)
'
i Ooened
50-413/96-12-01 VIO Failure To Follow Procedures-Two Examples
(Section E1.2).
+
l 50-413/96-12-02 VIO Failure To Adequately Train Welders To Perform
i Their Assigned Tasks (Section E1.2).
- 50-413.414/96-12-03 VIO Inadequate Design Controls For Ensuring
i
Containment Crane Wall And Floor Drain Screens
Implemented Design Requirements (Section E8).
]
- Closed
i
! 50-413.414/96-11-01 URI As Built Discrepancies Could Allow Debris
j Transport To Containment Sump Screens (Section
i
E8).
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LIST OF ACRONYMS USED
ANSI -
American National Standard Institute
1 ASME - American Society of Mechanical Engineers
i BB -
Blowdown Recycle
BW -
Wet Lay-up Recirculation
i BWI -
Babcock & Wilcox International
i
CA -
- CF -
Main Feedwater
i CFR -
Code of Federal Regulations
i
CNS -
Catawb6 Nuclear Station
ECCS - Emergency Core Cooling System
. ESS -
Electrical System Support
l FME -
. F0SAR - Foreign Object Search And Retrieval
' FSAR - Final Safety Analysis Report
FTI Framatome Technologies Inc.
I- FWDS - Field Weld Data Sheet
.
IR -
Inspection Report
NDE -
NC -
NRR -
Office of Nuclear Reactor Regulation
i NSD -
Nuclear Station Directive
'..
NSM -
Nuclear Station Modification
OD -
Outer Diameter
4 PIP -
Problem Investigation Process
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PWHT - Post Weld Heat Treatment
OA -
Quality Assurance
4
OC -
Quality Control
'
RCS -
SG -
- SGR -
Steam Generator Replacement
'
SGRP - Steam Generator Replacement Project
i SM -
. URI -
Unresolved Item
VIO -
Violation
i WPCS - Weld Process Control Sheet
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ENCLOSURE 2
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