ML022660611
| ML022660611 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 09/23/2002 |
| From: | Dan Collins NRC/NRR/DLPM/LPD1 |
| To: | Bezilla M FirstEnergy Nuclear Operating Co |
| Collins D S, NRR/DLPM, 415-1427 | |
| References | |
| TAC MB3906 | |
| Download: ML022660611 (5) | |
Text
September 23, 2002 Mr. Mark B. Bezilla Vice President FirstEnergy Nuclear Operating Company Beaver Valley Power Station Post Office Box 4 Shippingport, PA 15077
SUBJECT:
BEAVER VALLEY POWER STATION, UNIT NO. 2 -
SUMMARY
OF TELEPHONE CONFERENCE WITH FIRSTENERGY NUCLEAR OPERATING COMPANY REGARDING CURRENT STEAM GENERATOR INSPECTION RESULTS (TAC NO. MB3906)
Dear Mr. Bezilla:
The Nuclear Regulatory Commission (NRC) staff participated in a conference call with FirstEnergy Nuclear Operating Company (FENOC) on February 15, 2002, to discuss the results of the steam generator (SG) tube inspections that were being performed during the ninth refueling outage (RF09) at Beaver Valley Power Station, Unit No. 2 (BVPS-2). The NRC staff documented its request and suggested agenda for the telephone conference in a letter to FENOC dated February 8, 2002 (Agencywide Documents Access and Management System Accession No. ML012530154).
Topics discussed during this call included the inspection scope, the eddy current data analysis results, new degradation mechanisms, plugging and repair plans, in-situ pressure testing and actions taken in response to the Indian Point Unit 2 (IP2) tube rupture event and NRC Information Notice 2000-02 (IN 2002-02), Recent Experience with Plugged Steam Generator Tubes. Many of these details are contained in the enclosed inspection summary FENOC provided in support of this call. During the call, FENOC updated the number and depth of some flaw indications. These changes are noted below.
The inspection scope included both bobbin and rotating pancake coil (RPC) examinations of bobbin distorted signal indications (DSI) and hot leg Alloy 690 rolled plugs. During the call, FENOC updated the number of bobbin DSIs from 316 to 329 and confirmed four of these indications as Tube Support Plate (TSP) axial outer-diameter stress corrosion cracking (ODSCC). The maximum DSI voltage was 1.71; however, FENOC stated that this voltage may be higher after they completed the data evaluation. Although the BVPS-2 technical specifications allow use of the Generic Letter (GL) 95-05 alternate repair criteria (ARC), FENOC chose not to formally use the ARC because only 4 DSIs were confirmed as flaw-like. The NRC staff inquired about the nature of these indications with respect to their presence in previous outages and their confirmation with RPC probes. FENOC stated that these indications appear to be the same indications from previous outages with a slight increase in the voltages. In addition, FENOC theorized that the RPC probes have not been confirming most of the bobbin data because many of the DSIs may be shallow ODSCC indications that are more difficult to M. Bezilla detect with RPC. Although the NRC staff is aware that RPC probes will not confirm all bobbin indications, the NRC staff questioned the quantity of unconfirmed DSIs. With respect to plugged tubes at BVPS-2, FENOC reported that, in addition to Alloy 690 rolled plugs, BVPS-2 SGs also contain Alloy 600 rolled plugs that have been repaired with a plug-in-plug technique.
FENOC has visually inspected these plugs.
The NRC staff and FENOC discussed in detail the results of the bobbin and RPC inspections, including new degradation mechanisms such as axial primary water stress corrosion cracking (PWSCC) and axial ODSCC within freespan dings. During the examination of the bobbin mixed residual signals, FENOC identified a 1/2-inch, 2.7 volt, 51% maximum depth axial PWSCC indication at the 05H TSP in SG B. When FENOC identified this flaw, the analysts expanded the scope of the mixed residual analysis by increasing the phase angle from 45° to 50°.
Upon expanding the scope, another 2.2 volt, 25% through-wall, 0.3-inch axial PWSCC indication was identified at the 04H TSP in SG C. At the intersections with the axial PWSCC indications there were dents approximately one volt in magnitude. A third axial PWSCC indication was identified at the top of the tubesheet. These inspection findings are discussed in the enclosed material provided by FENOC.
During the call, FENOC reported that there were no tubes exceeding the screening criteria for in-situ pressure testing. The NRC staff asked if the Electric Power Research Institute (EPRI) guidelines address the performance of in-situ pressure testing upon discovering a new degradation mechanism. FENOC stated that EPRI guidelines do not suggest in-situ pressure testing tubes with new degradation mechanisms and did not express any plans to perform pressure testing. After the call, FENOC conducted in-situ pressure tests on the tubes with axial PWSCC and found that the in-situ leakage and 3P pressure tests were satisfactory. FENOC did not further increase the phase angle criteria because all tubes with phase angle indications 50° were inspected with no additional findings.
The second new degradation mechanism was one hot leg ODSCC indication within a ding located in SG A between the 02H and 03H TSPs. The licensee identified this flaw within a 20%
hot leg sample of >5 volt dings. As a result of this finding, the licensee expanded the sample to all hot leg dings greater than five volts in SG A. The licensee did not identify additional axial ODSCC indications within this expanded sample. The licensee indicated that new degradation mechanisms are tracked in the BVPS-2 corrective action program. Prior to the phone call, FENOC generated a condition report (CR) for the axial PWSCC indications. In addition, FENOC stated the intention to generate a CR for the axial ODSCC finding.
Other inspection findings included tubes in all SGs with volumetric, outer-diameter (OD) axial and OD circumferential degradation in the hot leg near the top of the tubesheet (TTS). SGs A and B each had one tube with volumetric indications that FENOC characterized as loose parts wear; however, no visual confirmation of any loose parts was performed near these tube locations. During the call, FENOC updated the maximum TTS circumferential ODSCC depth from 63% to 67%. A visual inspection of the secondary side revealed no swollen or severed plugged tubes. FENOC stated that although there have been no specific changes made to the SG inspection program in response to IN 2002-02, for the past few cycles (~ 3 cycles)
M. Bezilla and including RF09, all tubes with circumferential indications meeting the repair criteria were stabilized prior to plugging.
At the conclusion of the call, the NRC staff requested that FENOC contact the NRC project manager (PM) with any additional inspection results significantly different than those discussed.
On February 19, 2002, FENOC contacted the PM with the results of the sample expansion in SG A of hot leg dings > 5 volts and the in-situ pressure tests on the tubes with axial PWSCC.
These results are captured in the above discussion.
Based on the information provided during the conference call and on February 19, 2002, the staff did not identify any issues requiring further discussion.
Sincerely,
/RA/
Daniel S. Collins, Project Manager, Section 1 Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-412
Enclosure:
Discussion Points cc w/encl: See next page
M. Bezilla and including RF09, all tubes with circumferential indications meeting the repair criteria were stabilized prior to plugging.
At the conclusion of the call, the NRC staff requested that FENOC contact the NRC project manager (PM) with any additional inspection results significantly different than those discussed.
On February 19, 2002, FENOC contacted the PM with the results of the sample expansion in SG A of hot leg dings > 5 volts and the in-situ pressure tests on the tubes with axial PWSCC.
These results are captured in the above discussion.
Based on the information provided during the conference call and on February 19, 2002, the staff did not identify any issues requiring further discussion.
Sincerely,
/RA/
Daniel S. Collins, Project Manager, Section 1 Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-412
Enclosure:
Discussion Points cc w/encl: See next page DISTRIBUTION:
PUBLIC MOBrien ACRS PDI-1 Reading DCollins BPlatchek, RGN-I SRichards OGC ESullivan RLaufer CKhan ALLund ASmith DLew, RGN-I MModes, RGN-I KKarwoski Accession nos.:
Letter: ML022660611
Enclosure:
ML Package: ML OFFICE PDI-1/PM PDI-1/LA EMCB/SC PDI-1/SC NAME DCollins MOBrien memo from A. Louise Lund RLaufer DATE 09/23/2002 09/23/2002 03/27/02 09/23/2002 OFFICIAL RECORD COPY
Beaver Valley Power Station, Units 1 and 2 Mary OReilly, Attorney Rich Janati, Chief FirstEnergy Nuclear Operating Company Division of Nuclear Safety FirstEnergy Corporation Bureau of Radiation Protection 76 South Main Street Deparment of Environmental Protection Akron, OH 44308 Rachel Carson State Office Building P.O. Box 8469 FirstEnergy Nuclear Operating Company Harrisburg, PA 17105-8469 Regulatory Affairs/Corrective Action Section Larry R. Freeland, Manager Mayor of the Borough of Beaver Valley Power Station Shippingport Post Office Box 4, BV-A P O Box 3 Shippingport, PA 15077 Shippingport, PA 15077 Commissioner James R. Lewis Regional Administrator, Region I West Virginia Division of Labor U.S. Nuclear Regulatory Commission 749-B, Building No. 6 475 Allendale Road Capitol Complex King of Prussia, PA 19406 Charleston, WV 25305 Resident Inspector Director, Utilities Department U.S. Nuclear Regulatory Commission Public Utilities Commission Post Office Box 298 180 East Broad Street Shippingport, PA 15077 Columbus, OH 43266-0573 FirstEnergy Nuclear Operating Company Director, Pennsylvania Emergency Beaver Valley Power Station Management Agency ATTN: M. P. Pearson, Director 2605 Interstate Dr. Services and Projects (BV-IPAB)
Harrisburg, PA 17110-9364 Post Office Box 4 Shippingport, PA 15077 Ohio EPA-DERR ATTN: Zack A. Clayton FirstEnergy Nuclear Operating Company Post Office Box 1049 Beaver Valley Power Station Columbus, OH 43266-0149 Mr. B. F. Sepelak Post Office Box 4, BV-A Dr. Judith Johnsrud Shippingport, PA 15077 National Energy Committee Sierra Club 433 Orlando Avenue State College, PA 16803 L. W. Pearce, Plant Manager (BV-IPAB)
FirstEnergy Nuclear Operating Company Beaver Valley Power Station Post Office Box 4 Shippingport, PA 15077