IR 05000302/2011009
| ML111330350 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 05/12/2011 |
| From: | Mark Franke NRC/RGN-II/DRS/EB2 |
| To: | Franke J Florida Power Corp, Progress Energy Florida |
| References | |
| IR-11-009 | |
| Download: ML111330350 (328) | |
Text
May 12, 2011
SUBJECT:
CRYSTAL RIVER NUCLEAR PLANT - STEAM GENERATOR REPLACEMENT INSPECTION PROGRESS REPORT 05000302/2011009
Dear Mr. Franke:
On April 22, 2011, the U.S. Nuclear Regulatory Commission (NRC) completed inspections at
your Crystal River Unit 3 Nuclear Plant in accordance with NRC Inspection Procedure (IP)
50001, Steam Generator Replacement Inspection. The enclosed inspection report documents
inspection results, which were discussed on April 28, 2011, with you and members of your staff.
The inspections examined activities conducted under your license as they relate to safety and compliance with the Commission's rules and regulations and with the conditions of your license.
The inspectors reviewed selected procedures and records, observed activities, interviewed
personnel, and conducted plant walk downs, including visual examination of accessible portions
of the containment building structure.
In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and its
enclosure will be available electronically for public inspection in the NRC Public Document
Room or from the Publicly Available Reco rds (PARS) component of the NRC's Agencywide Documents Access and Management System (ADAMS
). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).
Sincerely,
/RA/
Mark E. Franke, Chief Operations Branch 2
Division of Reactor Safety
Docket No. 50-302
License No. DPR-72
Enclosures:
1: Inspection Report 05000302/2011009
w/Attachment: Supplemental Information
2: Licensee Question Tracking Database
REGION II Docket No.: 50-302
License No.: DPR-72
Report No.: 05000302/2011009
Licensee: Progress Energy (Florida Power Corporation)
Facility: Crystal River Unit 3
Location: Crystal River, FL
Dates: January 1, 2011 through April 22, 2011
Inspectors: R. Carrion, Senior Reactor Inspector L. Lake, Senior Reactor Inspector
Approved by: Mark E. Franke, Chief, Operations Branch 2
Division of Reactor Safety
Enclosure 1
SUMMARY OF FINDINGS
IR 05000302/2011009; 01/01-04/22/2011; Crystal River Unit 3; Steam Generator Replacement
Inspection
This report covered an infrequently performed Steam Generator Replacement Project (SGRP)inspection performed by regional reactor inspectors from January 1, 2011, through April 22, 2011. This report also includes a list of issued inspection reports and a summary of the SGRP inspections performed prior to December 31, 2010. The NRC's program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, "Reactor
Oversight Process," Revision 4, dated December 2006.
A. NRC-Identified
& Self-Revealing Findings No findings were identified.
B. Licensee-Identified Violations
None.
REPORT DETAILS
Background
The licensee scheduled the replacement of its steam generators during Crystal River Unit 3 (CR3) Refueling Outage 16, which began in September 2009. The steam generators are
housed in the reactor containment building. In preparation for the steam generator
replacement, the licensee evaluated options for moving the existing steam generators out of the
containment building and moving the new steam generators into the containment building. The
licensee decided to make a construction opening in the containment building wall, approximately forty feet directly above the equi pment hatch, to facilitate this evolution.
Fabricating the opening in the containment building wall included preparing the containment
building by detensioning its pre-stressed tendons and then removing the concrete with high
pressure water (a process known as hydro-demolition), removing the rebar and tendons from
the area of the construction opening, and cutting the containment liner plate. A concrete
delamination in Bay 3-4 of the containment structure was discovered while creating the SGR
opening in October 2009. The licensee determined that the root cause of the delamination was
related to the scope and sequence of the tendon detensioning process.
The licensee's containment building repair plan included:
- (1) additional detensioning of
containment;
- (2) removal of delaminated concrete;
- (3) installation of reinforcement, including
radial reinforcement through the delamination plane;
- (4) placing of new concrete;
- (5) retensioning containment; and
- (6) post-repair confirma tory system pressure testing. In early 2011, the licensee had completed repair steps 1 through 4 and was in the process of
retensioning the containment. On March 14, 2011, during the final stages of the re-tensioning
process, the licensee had indications that a new delamination occurred in Bay 5-6 of the
containment structure.
Since September 2009, and through the end of this inspection period, Crystal River Unit 3 has
remained shutdown, a mode of operation where containment building operability is not required.
The purpose of this inspection report is to document all inspection activities performed related to
the steam generator replacement project for Unit 3 containment restoration activities including
repairs due to the concrete delamination identified in October 2009.
OTHER ACTIVITIES
[OA]
4OA5 Steam Generator Replacement Inspection (IP50001)
.1 SGRP Inspection Activities through December 31, 2010
Inspection of the licensee's SGRP began in September 2009 when the inspectors
reviewed the preparations for heavy load movement and lifting and started the review of
the design modifications associated with the project. Inspection of the licensee's SGRP
continued in the fourth quarter of 2009 and throughout 2010. Results of the SGRP
inspections are documented in the quarterly integrated resident inspector reports. The
following is a summary of the activities inspected. Details of the inspections can be
found in the following inspection reports:
Inspection Report ADAMS ML # Report Section 05000302/2009004 ML093030165 4OA5.2 05000302/2009005 ML100250014 4OA5.2 05000302/2010002 ML101170619 4OA5.3 05000302/2010003 ML102090239 4OA5.2 05000302/2010004 ML103020127 4OA5.3 05000302/2010005 ML110270190 4OA5.2 Design and Planning The inspectors reviewed and examined the SGRP activities and compared them to the
requirements of the American Society of Mechanical Engineers (ASME) Code. The
inspectors reviewed Engineering Change (EC) 63038, Replacement Once Through
Steam Generators (ROTSGs or RSGs), which included the design changes, analyses, evaluations, safety analyses, 10 CFR Part 50.59 change evaluation, configuration, materials, implementation, and post-modification testing acceptance. The inspectors
reviewed EC 62500, RCS Hot Leg Cutting and Welding, EC 63016, Containment
Opening; EC 63025, Main Feedwater Flow Accelerated Corrosion (FAC) Pipe
Replacement, EC 63026, RCS Cold Leg Cutting and Welding, EC 63027, Secondary
Side Large Bore Pipe Cutting and Welding, EC 63034, Structural Interferences, and EC 63039, Replacement Steam Generator Anchorage. The inspectors also reviewed
selected work order (WO) packages prepared for the construction and implementation of
the ECs to determine whether appropriate work processes and quality control hold
points were implemented.
Steam Generator Removal and Replacement During the hydro-demolition process to create the construction opening in the
containment wall, the licensee identified concrete cracks/separations. The concrete
separations were located within the entire perimeter of the opening. An NRC Special
Inspection Team was chartered to inspect the separation issues. Results of the Special
Inspection, including the licensee's root cause analysis, are documented in NRC
Inspection Report 05000302/2009007 (ML1028610261). The licensee evaluated the
containment wall cracks to modify the hor izontal transfer system (HTS) supporting structures. Prior to the removal of the original steam generators (OSGs), the inspectors
reviewed, observed, and evaluated the associated temporary and permanent
modifications of the cutting, disconnecting, and the providing of temporary supports for
the OSGs and cutoff piping. The inspectors observed lifting, rigging, downending and
upending, and transporting of the OSGs, RSGs, and associated equipment; machining
and preparations of the existing piping for the connections to the RSGs; welding and
non-destructive examination (NDE) activities; and the radiological safety plan for the
temporary storage and disposal building of the retired steam generators. The inspectors
reviewed and observed the major structural modifications. The inspectors observed the
licensee performance inspection of the steam generator hold-down bolts to verify that
the bolts were acceptable to hold down the RSGs after the OSGs were moved from their
cubicles. During the steam generator (SG) removal and replacement, the inspectors
observed licensee activities associated with controls for excluding foreign material, including the primary and secondary side of the steam generators and in the related
RCS openings, and the establishment of operating conditions including defueling, RCS
draindown and system isolation. The inspecto rs also reviewed procedures, examination results, modification packages, and WO packages related to the modifications, including the construction opening steel containment vessel (SCV)reinstallation, to ensure compliance with the requirements of the ASME Code.
RSG Fabrication, Preservice Inspection, and Baseline Inspection The inspectors reviewed records associated with the materials, fabrication, examination, and testing for the RSGs, and replacement hot leg piping subassemblies ("Candy
Canes"), to verify compliance with the ASME Code. The inspectors also reviewed
documentation and interviewed plant personnel regarding the pre-service and baseline
testing of RSG tubing. The inspectors also reviewed documentation regarding the
manufacture of the RSG tubing, including heat treatment records and nonconformance
reports.
Welding The inspectors reviewed a sample of welding activities associated with the installation of
the RSGs to evaluate compliance with licensee/contractor procedures and the applicable
ASME Code. The inspectors reviewed joint configuration drawings, welding procedures, welding specifications, welding procedure qualifications, welder qualification records, weld data records, nuclear condition reports (NCRs), and post-weld heat treatment
procedures.
Non-Destructive Examination The inspectors reviewed the NDE procedures, calibration and examination reports, and
NCRs, and observed in-process NDEs, including liquid penetrant examinations (PTs),
magnetic particle examinations (MTs), radi ographic examinations (RTs), and ultrasonic examinations (UTs), and compared them to the requirements of the procedures and the ASME Code for the construction, pre-service, and baseline inspections.
Containment Construction Opening and Closure - Steel and Concrete Containment The inspectors reviewed the licensee's activities associated with the concrete removal
and the removal and restoration of the steel containment liner plate (SCLP) for the
containment construction hatch opening, as detailed in the EC 63016, Containment
Opening. The inspectors reviewed the plans for the cutting and restoration of the SCLP
for the construction opening and compared post-testing requirements to the applicable
ASME Code. The inspectors observed the hydro-demolition of concrete for the
containment construction opening and reviewed the WO packages for the cutting of the
liner plate to verify that the steps had been completed and documented. The inspectors
also reviewed the welding procedures, procedure qualification records, and welder
qualification records to confirm that the Code-required essential and supplemental
essential welding variables were met. The inspectors reviewed the WO packages, including welding electrode receipt inspection, vacuum box leak testing, MT records, material certification records, and qualification and certification records for NDE
personnel, equipment, and consumables.
Heavy Load, Rigging, Lifting, and Transporting Activities The inspectors reviewed the SG lifting preparation activities and lifting equipment load
test data to ensure that they were prepared in accordance with regulatory requirements, appropriate industrial codes and standards, and to verify that the maximum anticipated loads to be lifted would not exceed the capacity of the lifting equipment and supporting structures. The inspectors reviewed procedures, calculations, drawings, work packages, crane and equipment operator training and certificates, and load and function test
records to verify that they were in accordance with regulatory requirements and
appropriate industrial codes and standards. The inspectors also examined SGRP lifting, rigging, and transporting equipment, including the polar crane, mobile crane, the
Temporary Lifting Device (TLD), the Horizontal Transfer System (HTS) (including its skid
system), the down/upender device, the Outside Lift System (OLS), and the self-propelled modular transporter (SPMT). The inspectors observed a selective sampling of rigging, lifting, transportation, and positioning of the original and replacement SGs.
Quality Assurance (QA) Program and Corrective Actions The inspectors conducted a review of the quality assurance program and its
implementation for the SG replacement to assess compliance with the requirements of
10 CFR Part 50, Appendix B. The inspectors also reviewed the surveillance reports and
nonconformance reports issued for the root cause analyses, evaluations, repairs, or
disposition during the manufacturing of the RSGs.
SG Post-Installation Verification and Testing The inspectors reviewed the SG post-installation verification and testing program to
verify that the required post-installation verification and testing, procedural changes, and
the adjustment of the instruments were properly identified.
Containment Detensioning The inspectors conducted a review of the licensee's detensioning activities for the repair
of the delaminated containment wall and restoration of the containment wall to it
pre-construction opening condition, including associated ECs and Work Packages (WPs). The inspectors also observed vertical and horizontal tendon detensioning. The
inspectors observed and reviewed the records of the acoustic monitors and strain
gauges used to detect sound volumes and concrete strain changes potentially due to
new cracks or compressive or tensile stress changes in the concrete during the
detensioning process. The inspectors reviewed the procedures, drawings, calibrations, equipment and personnel qualifications, and the tendon detensioning communication
plan associated with detensioning to verify that the licensee performed the activities in
accordance with approved procedures.
Concrete Removal, Surface Preparation, and Concrete Placement Activities The inspectors conducted a review of the licensee's activities associated with the
removal of the damaged concrete and restoration of the containment wall. The
inspectors reviewed associated documents, including ECs, WPs, specifications, drawings, test reports, and NCRs. The inspectors observed the process of the
hydro-demolition of damaged concrete, the surface preparation of concrete after the
hydro-demolition, and pull-out testing to assure that the concrete surface would have
enough tensile strength to bond the new and original concrete. The inspectors reviewed
radial rebar drilling; grouting; and identified void problems, and their respective
resolutions. The inspectors observed rebar and formwork installation and tendon sleeve
condition in preparation of the concrete pour. The inspectors also reviewed the
associated engineering packages, WPs, and drawings to verify that licensee activities were performed in accordance with approved documents. The inspectors observed concrete placement activities to verify that activities pertaining to concrete delivery time, flow distance, layer thickness, etc. conformed to industry standards established by the
American Concrete Institute (ACI). The inspectors also observed that concrete
placement activities were monitored by the licensee and contractor's quality control
personnel and engineers. The inspectors observed in-process concrete testing and
reviewed the results for slump, air content, temperature, and unit weight, to verify that
this was done in accordance with applicable American Society for Testing and Materials (ASTM) requirements. The inspectors checked the batch plant for its certification and
reviewed its preparation for the concrete pour. During the concrete placement activities, the inspectors identified a finding of very low safety significance and an associated non-cited violation (NCV) of 10 CFR Part 50, Appendix B, Criterion IX, "Control of Special
Processes," for the licensee's failure to establish measures to assure that testing of
rebar splices would adhere to the requirements of ASME Boiler and Pressure Vessel
Code. (Refer to Section 4OA5.3 of Inspection Report 05000302/2010004 (ML103020127) for additional details about NCV 05000302/2010004-03, Failure to
Submit Production Splices of Swaged Mechanical Splices for Testing.)
Containment Dome Cracks On April 14, 1976, a delamination was identified in the containment dome during the final
stages of containment construction and before initial plant startup. The area of the
delaminated concrete was approximately circular in shape with a 105-foot diameter. The
dome repair process included removal of the delaminated dome cap; removal of
meridional, hoop, and radial reinforcement; and placement of a new dome cap.
Instrumentation was installed to monitor the dome during tendon detensioning, retensioning and the initial structural integrity. As part of the Special Inspection to
assess the circumstances associated with the delamination discovered in 2009, NRC
inspectors conducted a review of the licensee's conclusion that the delamination
identified in 1976 is not related to the current delamination. Additional background
information and the results of these inspections are presented in NRC Inspection Report 05000302/2009007 (ML1028610261).
In 2009, NRC Special Inspection Team inspectors conducted concrete surface
inspections on the containment dome and identified a rough and uneven surface
condition of the dome surface. The inspectors reviewed the evaluation and corrective
action that determined the rough and uneven surface condition of the dome has existed
since the 1976 repair. The licensee had periodically completed numerous surface
patches in an attempt to address the surface spalls. Following additional reviews of the
dome tendon stresses and monitoring, the uneven surface also appeared to be a result
of concrete installation and finishing from the 1976 repair and not related to settlement of
the dome or the 2009 containment concrete wall delamination issue.
In 2010, the inspectors reviewed a condition assessment of the containment dome
documented in the licensee's engineering change package EC 74801. The licensee had
included this assessment in the activities associated with its 2009 containment extent-of-
condition investigation. Included was Impulse Response (IR) testing and core bores
made in support of evaluating the IR data. Anomalies were identified and, to evaluate
the anomalies, additional examinations were performed. A total of about 10,000 points
were tested and a total of 30 core samples were removed. Visual inspections were
performed of each core sample and a video scope inspection of each core hole was
performed after the core sample was removed. This evaluation revealed cracking in the plane of the dome (laminar cracking). The licensee determined that these anomalies were remnants of the repairs performed in 1976.
The inspectors reviewed the CTLGroup Project No. 059176 - Dome Report, which
included the results of the examinations identified above. The information contained in
this report was subsequently utilized in an engineering evaluation documented in
Containment Dome Evaluation, Report No. CR-3-LI-537934-52-SE-0059. The
engineering evaluation determined that the repairs made to the dome structure in 1976
are intact; that there are no significant anomalies, discrepancies, or structural issues
which would affect the overall structural integrity of the dome structure; and that the
structure is capable of performing its design basis functions as described in the Updated
Final Safety Analysis Report (UFSAR).
Additional information is presented in NRC Inspection Report 05000302/2009007 (ML1028610261).
Containment Tendon Retensioning Plan The inspectors reviewed the containment tendon retensioning plan, testing plan, and
schedule. The inspectors also interviewed licensee personnel and reviewed documents
related to the retensioning and testing plans. The licensee conducted a detailed
analysis to develop a tendon retensioning sequence that would minimize the possibility of causing new cracks or delaminations in the containment during the retensioning
process. The retensioning process began in January 2011. The inspectors also
reviewed licensee plans for Containment Building testing after completion of tendon
retensioning and post-maintenance testing after restart.
.2 SGRP Inspection Activities January 1, 2011 through April 22, 2011
Discussion of Technical Issues The following issues were discussed with licensee personnel during this inspection
period: Bulges of Liner Plate The inspectors completed a review of the licensee's actions related to containment liner
bulges. The licensee developed a calculation to evaluate bulges in the CR3
containment liner plate. It was directed at determining an apparent cause for the bulges
and establishing an analytically-based acceptance criterion for the bulges within the CR3
design basis. The analyses included finite element modeling of the liner and the
associated anchorage to the concrete containment structure. The apparent cause for
the bulges was determined to be a combination of elements, including geometrical
imperfections in the original liner plate during construction. The calculations considered
worst case configurations and a threshold for bulge size was established considering the
effects that occur due to normal operation and accident conditions. The primary
variables in the bulge evaluation were determined to be bulge size and thermal loading.
The calculation found that the bulges have an insignificant effect on the response of the
structure due to various load combinations. The current bulges are bounded by the
acceptance criteria in the analysis. To ensure that conditions are acceptable in the
future, the licensee planned to include the bulges in the IWE program. The licensee
added a summary evaluation to the EC, which includes steps to validate the effect of retensioning on bulge size by measurement and evaluation of a representative sample before initiating Structural Integrity Test (SIT) pressurization as well as requirements to
perform a complete baseline scan after completion of the SIT.
50.59 Evaluation The inspectors reviewed the licensee's evaluation of the containment building
modification resulting from the introduction of the construction opening and its
subsequent restoration with respect to requirements of 10 CFR, § 50.59, Changes, Tests and Experiments, to verify that the design bases, licensing bases, and
performance capability of the containment had not been degraded through the
modification and to verify that the design and license basis documentation used to
support changes reflect the design and license basis of the facility after the change had
been made.
The inspectors' review remained ongoing at the end of the inspection period. Remaining
activities necessary to complete the 50.59 review included: verification that tendon
retensioning activities and containment testing validated licensee design assumptions;
verifying that post-modification testing adequately confirmed containment functionality
via the scheduled Structural Integrity Test (SIT) and Integrated Leak Rate Test (ILRT)
prior to unit startup; verifying that design basis documentation used to support changes
and design basis documentation affected by changes had been adequately updated and
reflected the modified design and license basis of the facility consistent with the
restoration; and verifying that the license's UFSAR had been updated accordingly.
Vertical Cracks of Containment Building One of the licensee's design assumptions for containment repair was that vertical cracks discovered on the exterior wall of the containment building would close as the building's tendons were retensioned. The inspectors walked down selected vertical cracks being monitored by the licensee to evaluate their condition. The licensee had measured the cracks periodically and determined that they were closing as the tendon retensioning process continued. The inspectors also visited the tendon control center where the retensioning process was controlled, and which housed the acoustic monitoring and strain gage instrumentation, and interviewed personnel in the center to better understand the operation of the systems being used and how the information obtained was interpreted.
The inspectors' review of vertical cracks remained ongoing pending inspection of the containment building after all repairs are completed and tendons are fully retensioned, and the completion of the SIT and ILRT.
Tendon Re-tensioning Activities The inspectors reviewed the licensee's re-tensioning plans, procedures, and drawings.
In addition the inspectors observed some of the re-tensioning work being performed on
selected hoop tendons to verify that the work was being conducted per approved
procedures.
SIT/ILRT Preparations The inspectors interviewed licensee personnel responsible for the planned SIT/ILRT to
determine the status of the test preparations; walked down the containment building to
verify the locations of the extensometers to be used to measure the containment
movements during the SIT/ILRT; and discussed the licensee's procedures to ensure that
they conformed to industry standards and ASME Code requirements.
Events of March 14, 2011 On the afternoon of March 14, 2011, the licensee had completed the first retensioning
sequence (Sequence #100, Hoop Tendons 42H41, 62H41, and 64H41) of the final pass (Pass #11). Per procedure, the licensee was waiting for the containment building to
stabilize before beginning the next sequence and monitoring the structural behavior of
the containment building via acoustical emissions monitors and strain gauges, specifically placed at various points of the structure to detect any abnormal/unexpected
response to tendon retensioning. During this monitoring period, the strain gauges
indicated an increase in strain and then failed high, and the acoustic monitors indicated
a high level of acoustic activity in the bay bordered by Butresses #5 and #6 (Bay 5-6).
The phenomenon reportedly lasted for about twenty minutes. The licensee conducted
impulse response (IR) non-destructive examination NDE techniques to determine the
condition of the wall in Bay 5-6. The IR scans of the bay determined that there were
numerous indications consistent with a delamination. By the end of the inspection
period, the licensee had determined that the delamination was extensive in Bay 5-6 and
was continuing to evaluate the condition of the entire containment structure. Future
inspection activities by the NRC relating to the March 14, 2011, event are to be
determined.
4OA6 Meetings, Including Exit
Exit Meeting Summary
On April 28, 2011, the inspectors presented the inspection results to Mr. J. Franke, Site
Vice President, and other members of licensee management via a telephone call. The
inspectors confirmed that proprietary info rmation was not provided or examined during the inspection.
ATTACHMENT:
SUPPLEMENTAL INFORMATION
KEY POINTS OF CONTACT
Licensee personnel
- S. Cahill, Manager, Engineering
- P. Dixon, Progress Energy
- G. Flavors, Nuclear Upgrades
- J. Franke, Site Vice-President
- T. Howard, Engineering
- J. Holt, Site General Manager
- J. Huegel, Nuclear Oversight
- M. Rigsby, Manager - Support Services
NRC personnel
- D. Rich, Chief, Branch 3, Division of Reactor Projects
- T. Morrissey, Senior Resident Inspector
- R. Reyes, Resident Inspector
LIST OF ITEMS
OPENED, CLOSED AND DISCUSSED
Opened
None.
Closed
None.
Discussed
- 05000302/2010004-03 NCV Failure to Submit Production Splices of
Swaged Mechanical Splices for Testing