L-13-197, Response to Request for Additional Information on 10 CFR 50.55a Request RR-A37
| ML13206A308 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 07/24/2013 |
| From: | Lieb R A FirstEnergy Nuclear Operating Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| L-13-197, TAC MF0752 | |
| Download: ML13206A308 (14) | |
Text
FE NOCŽ FirstEnergy Nuclear Operating Company Raymond A Lieb Vice President, Nuclear July 24, 2013 L-13-197 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
SUBJECT:
Davis-Besse Nuclear Power Station Docket No. 50-346, License No. NPF-3 5501 North State Route 2 Oak Harbor, Ohio 43449 10 CFR 50.55a 419-321-7676 Fax: 419-321-7582 Response to Request for Additional Information on 10 CFR 50.55a Request RR-A37 (TAC No. MF0752) By correspondence dated February 27, 2013 (Accession No. ML 13059A315), FirstEnergy Nuclear Operating Company (FENOC) submitted 10 CFR 50.55a Request RR-A37 for the Davis-Besse Nuclear Power Station. By electronic mail dated June 27, 2013 (Accession No. ML 13179A095), the Nuclear Regulatory Commission (NRC) additional information to complete its review of Request RR-A37. FENOC's response to this request is attached.
Additionally, the performance demonstration qualification summary, as requested in item 6 of the request for additional information, is provided as an enclosure.
There are no regulatory commitments contained in this submittal.
If there are any questions or additional information is required, please contact Mr. Thomas A. Lentz, Manager -Fleet Licensing, at (330) 315-6810.
Attachment:
Response to June 27, 2013 Request for Additional Information
Enclosure:
Performance Demonstration Qualification Summary (PDQS) No. 651 cc: NRC Region Ill Administrator NRC Resident Inspector NRC Project Manager Utility Radiological Safety Board Attachment L-13-197 Response to June 27, 2013 Request for Additional Information Page 1 of 9 By correspondence dated February 27, 2013, FirstEnergy Nuclear Operating Company (FENOC) submitted a 10 CFR 50.55a Request for Nuclear Regulatory Commission (NRC) review and approval. By elec tronic mail dated June 27, 2013, NRC staff requested additional information to complete its review.
The requested information is presented in bold type, followed by the FENOC response.
- 1. The licensee states in Proposed Alternative and Basis for Use
- "Based on radiological survey results from the spring 2012 refueling outage, this work would occur within radiation fields with dose rates up to 500 milli-Rem per hour, resulting in a significant increase in occupational radiation exposure
[dose] to personnel." The Examinat ion Data Sheet for the examination performed on May 15, 2012, indicated that the examination required nearly one hour, but the UT Examination Summary documented a total dose of 32 milli-
Rem for the examination.
- a. Explain the apparent discrepancy in the dose rate and the total radiological dose. Response: The total radiological dose of 32 milli-Rem (mR), as cited on the May 15, 2012 weld examination summary document, was the re sult of performing the ultrasonic (UT) examination with shielded pipi ng adjacent to the weld. T he 32 mR is for the weld examination itself; it does not include any ancillary activities, such as installing and subsequently removing access scaffolding or radiological shielding.
A spring 2012 refueling outage radiological survey used during development of Request RR-A37 revealed a maximum dose ra te of 500 mR/hour on contact with the cold leg drain pipe. Therefore, should the piping require a modification, this work would occur within radiation fields with dose rates up to 500 mR/hour.
- b. Justify why the dose incurred would present a hardship.
Response: Radiological dose does not present a hardship; however, unnecessary dose to personnel should be avoided. As discu ssed during a FENOC-NRC teleconference on June 26, 2013, implementing a modification to reroute the American Society of Mechanical Engineers (ASME) Class 1 piping would require offloading the reactor core, flushing and draining the system, installing (and subsequently removing) scaffolding and rigging, cutting out the exis ting piping, removi ng associated pipe supports, installing new pipe supports, installing a new section of piping, and performing any requisite examinations.
Though detailed planning and man-hour estimates for the modification do not exist, it is roughly estimated that several hundred man-hours of work would occur within radiation fields with dose rates up to 500 mR/hour, resulting in a significant increase in occupational radiation exposure [dose]
to personnel involved with implementing the modification.
Attachment L-13-197 Page 2 of 9
- 2. The NRC staff is unable to determine the exact volumes that were examined and the part of the required volume that was not examined from the drawings provided in the proposed alternative.
Provide clear scale drawings (with scale indicated) of the subject DMBW [dissimilar metal butt weld], including weld butter and FSWOL [full structural weld overlay] indicated. Clearly show the American Society of Mechanical Engineers (ASME) Boiler and Pressu re Vessel Code (Code) Case N-770-1 required examination volume and the volu me of material in terrogated by the examination in the axial and circumferential scan directions.
Response: The requested information is provided in Figures 1 and 2.
- 3. Provide a table detailing the scan coverage achieved for each of the following:
- a. carbon steel nozzle; b. stainless steel elbow;
- c. susceptible weld metal; and
- d. full structural weld overlay.
Provide values for scans in the circumferential and axial directions.
Response: The requested information is provided in Figures 3 and 4 with coverage values expressed as percentages.
- 4. The licensee states that "limitations imposed by the weld geometry" resulted in incomplete scan coverage. Describe these limitations and their effects on
scan coverage.
Response: The whole footprint of t he search unit must be on the examination surface during scanning. At the point where the search unit loses contac t with the surface or hits an obstruction is where the exit point of the sound beam is measur ed. Examples of this limitation, which results in reduced or incomplete scan coverage values, would be the FSWOL tapers or elbow intrados. Figure 5 provides an example.
Attachment L-13-197 Page 3 of 9
- 5. The technical report detailing the preservice examination of Cold Leg Drain Nozzle 1-2 (ISI Component ID RC-40-CCA-18-3-FW9)
FSWOL in 2010, "Summary of Weld Overlay Ultrasoni c Examinations for Reactor Coolant Pump Suction and Discharge Welds, Core Flood Nozzle Welds, and Cold Leg Drain Line Welds at Davis-Besse Nuclear Power Station, Unit 1" (ADAMS Accession No. ML101230641), states "100 percent axial scan coverage and 80.1 percent circumferential scan coverage of the ASME Code Case N-740 [8] required volume, as documented in the Relief Request [5], was achieved during the examinations."
- a. Why does the current examination not achieve 100 percent coverage for scans in the axial direction and at least 80 percent coverage for scans in the circumferential direction?
Response: The winter 2010 refueling outage (1R16) preservice inspection examination limited examination calculations we re not correct. The spring 2012 refueling outage (1R17) inservice inspection examination limitation calculation is correct. The noted discrepancies have been entered and addressed within FENOC's corrective action program. The 1R17 calcul ated coverage values have subsequently been verified with field measurements and detailed co verage drawings. The 1R17 coverage calculations are more conservative than those documented in the 1R16 examination and will be used for all future examinations. The 1R17 calculated coverage values were used in Request RR-A37. For alignm ent and consistency, the 1R16 datasheet has been updated to reflect the 1R17 calculated coverage values.
- b. Provide a detailed explanation for the differences in examination coverage between the preservice and the cu rrent inservice examination.
Response: Response to RAI 5a contains the requested information.
- 6. Provide a copy of the Performance Demonstration Qualification Summary (PDQS) for the UT examination procedure used. Describe any limitations of the ASME Code,Section XI, Appendix VIII qualified examination procedure.
Response: A copy of the PDQS is provided as an enclosu re to this letter.
Limitations on its use are specifically described in the PDQS.
- 7. Was the subject inservice examination performed by team scanning?
Response:
Attachment L-13-197 Page 4 of 9
No. The inservice examinati on was performed by one individual.
Note: Acronyms or symbols used on the following figures
- Dissimilar Metal Weld: DMW Square Inch: sq. in.
Ultrasonic: UT Percent: %
Carbon Steel: CS Stainless Steel: SS Full Structural Weld Overlay: FSWOL 1-2 RCS COLD LEG DRAIN NOZZLE INTRADOSE 90 deg.270 deg.EXTRADOSE 1.55 - TOTAL 1.61 - TOTAL 1.18 - 100%
1.18 / 1.55 = .761 1.14 / 1.61 = 70%
1.14 - 100%
CIRC. COVERAGE 76%EXTRADOSE = 76%
INTRADOSE = 70%
90 deg. = 68%
270 deg. = 73%
Circ. Composite = 71%
B P A C 1.15 - 100%
1.57 TOTAL 1.15 / 1.57 = .73 1.54 - TOTAL 1.06 - 100%
1.06 / 1.54 = .68 70%68%73%RC-40-CCA-18-3-FW9 OVERLAY 1.0"1.0" A ttachment L-13-197 Pa g e 5 of 9 Fi gure1OutlineofUTEquipment (typical)CIRCUMFERENTIALCOVERAGE1.55sq.in.=TOTAL[areaofinterest]
1.18sq.in.=scanachieved[2directions]
1.18/1.55=0.76 76%coverageEXTRADOSE=76%
INTRADOSE=70%
90Degrees=68%
270Degrees=73%
CircumferentialComposite=71%coverage1.61sq.in.=TOTAL[areaofinterest]
1.14sq.in.=scanachieved[2directions]
1.14/1.61=0.70 70%coverage1.54sq.in.=TOTAL[areaofinterest]
1.06sq.in.=scanachieved[2directions]
1.06/1.54=0.68 68%coverage90Degrees270Degrees1.57sq.in.=TOTAL[areaofinterest]
1.15sq.in.=scanachieved[2directions]
1.15/1.57=0.73 73%coverage EXTRADOS INTRADOSElbow(typical)Nozzle(typical)SSCladding Butter DMW FSWOLRequiredexamination volume(typical)
SCALE 1-2 RCS COLD LEG DRAIN NOZZLE INTRADOSE 90 deg.270 deg.EXTRADOSE 1.55 - TOTAL 1.61 - TOTAL 0.83 - 100%
0.64 - 50%
0.60 - 50%
0.68 - 100%
AXIAL COVERAGE
(.64 x .5) + .83 = 1.15 / 1.55 = .74 74%(.60 x .5) + .68 = .98 / 1.61 = .60 EXTRADOSE = 74%
INTRADOSE = 60%
90 deg. = 69%
270 deg. = 73%
Axial Composite = 69%
B P A C 0.76 - 100%
1.57 TOTAL 0.79 - 50%
1.54 - TOTAL 0.72 - 100%
0.70 - 50%
60%(.70 X .5) + .72 = 1.07 / 1.54 = .694 69%(.79 X .5) + .76 = 1.155 / 1.57 = .735 73%RC-40-CCA-18-3-FW9 OVERLAY 70 - 50%1.0"1.0" A ttachment L-13-197 Pa g e 6 of 9Figure2OutlineofUTEquipment (typical)EXTRADOS=74%
INTRADOS=60%
90Degrees=69%
270Degrees=73%
AxialComposite=69%coverage EXTRADOS INTRADOS90Degrees270Degrees1.55sq.in.=TOTAL[areaofinterest]
0.83sq.in.=scanachieved[2directions]
0.64sq.in.=scanachieved[1direction]
(0.64x0.5)+0.83=1.15 1.15/1.55=0.74 74%coverage1.61sq.in.=TOTAL[areaofinterest]
0.68sq.in.=scanachieved[2directions]
0.60sq.in.=scanachieved[1direction]
(0.60x0.5)+0.68=0.98 0.98/1.61=0.60 60%coverage1.54sq.in.=TOTAL[areaofinterest]
0.72sq.in.=scanachieved[2directions]
0.70sq.in.=scanachieved[1direction]
(0.70x0.5)+0.72=1.07 1.07/1.54=0.69 69%coverage1.57sq.in.=TOTAL[areaofinterest]
0.76sq.in.=scanachieved[2directions]
0.79sq.in.=scanachieved[1direction]
(0.79x0.5)+0.76=1.15 1.15/1.57=0.73 73%coverageElbow(typical)Nozzle(typical)
DMW ButterSSCladding FSWOLRequiredexamination volume(typical)
SCALE 1-2 RCS COLD LEG DRAIN NOZZLE INTRADOSE 90 deg.270 deg.EXTRADOSE CIRC. COVERAGE RC-40-CCA-18-3-FW9 OVERLAY CS Nozzle Base Material Susceptible Weld Metal SS Elbow Base Material FSWOL Material 0.08 0.13 0.04 1.31 Section Total Area (sq. in.)Coverage (sq. in.)Scan Coverage 100%100%50%(ACTUAL / TOTAL )
92%0%74%EXTRADOSE CS Nozzle Base Material Susceptible Weld Metal SS Elbow Base Material FSWOL Material Section Total Area (sq. in.)Coverage (sq. in.)Scan Coverage 100%50%(ACTUAL / TOTAL )
INTRADOSE 0.09 0.14 1.27 0.09 0.11 N/A CS Nozzle Base Material Susceptible Weld Metal SS Elbow Base Material FSWOL Material Section Total Area (sq. in.)Coverage (sq. in.)Scan Coverage 100%50%(ACTUAL / TOTAL )
90°0.07 0.12 0.06 1.27 0.07 N/A 100%83%
0%
70%CS Nozzle Base Material Susceptible Weld Metal SS Elbow Base Material FSWOL Material Section Total Area (sq. in.)Coverage (sq. in.)Scan Coverage 100%50%(ACTUAL / TOTAL )
0.06 0.13 0.06 1.32 100%100%0%73%270°100%78%0%72%0.08 0.12 0.0 0.98 N/A N/A N/A N/A N/A N/A N/A N/A 0.11 0.92 0.11 0.89 0.00 N/A N/A N/A 0.06 0.13 0.97 0.00 N/A N/A N/A N/A
A ttachment L-13-197 Pa g e 7 of 9Figure3OutlineofUTEquipment (typical)Elbow(typical)Nozzle(typical)
INTRADOS EXTRADOS90Degrees270Degrees90Degrees270DegreesCIRCUMFERENTIALCOVERAGE DMW ButterSSCladding FSWOLRequiredexamination volume(typical) 91%
1-2 RCS COLD LEG DRAIN NOZZLE INTRADOSE 90 deg.270 deg.EXTRADOSE AXIAL COVERAGE RC-40-CCA-18-3-FW9 OVERLAY CS Nozzle Base Material Susceptible Weld Metal SS Elbow Base Material FSWOL Material 0.08 0.13 0.04 1.31 Section Total Area (sq. in.)Coverage (sq. in.)Scan Coverage 0.08 100%0.04 0.09 100%50%N/A (ACTUAL / TOTAL )
0.04 65%50%0.7 0.53 73%N/A EXTRADOSE CS Nozzle Base Material Susceptible Weld Metal SS Elbow Base Material FSWOL Material Section Total Area (sq. in.)Coverage (sq. in.)Scan Coverage 100%50%(ACTUAL / TOTAL )
INTRADOSE 0.09 0.14 1.270.070.03 0.05 0.11 0.09 0.11 0.64.54 N/A CS Nozzle Base Material Susceptible Weld Metal SS Elbow Base Material FSWOL Material Section Total Area (sq. in.)Coverage (sq. in.)Scan Coverage 100%50%(ACTUAL / TOTAL )
90°0.07 0.12 0.06 1.27 0.07 0.06 0.03 0.09 0.65 0.52 N/A N/A 100%62%50%71%CS Nozzle Base Material Susceptible Weld Metal SS Elbow Base Material FSWOL Material Section Total Area (sq. in.)Coverage (sq. in.)Scan Coverage 100%50%(ACTUAL / TOTAL )
0.06 0.13 0.06 1.320.040.02 0.04 0.09 0.060.580.70 N/A 66%65%50%75%270°1.0" 1.0" 72%75%40%71% A ttachment L-13-197 Pa g e 8 of 9Figure4OutlineofUTEquipment (typical)Elbow(typical)Nozzle(typical)270Degrees270Degrees90Degrees90Degrees EXTRADOS INTRADOSSSCladding Butter DMW FSWOLRequiredexamination volume(typical)
SCALE
Figure 5 - Example of Methodology for Limited Scanning Measurements Sound exit point is measured at the point where any part of the SU scan surface looses contact with the component surface. (i.e. taper)
Scanning continues until sound beam signal is lost, however this scanning area is not factored into the limited scan calculations.
Scan up to any physical
limitations to SU movement.(i.e. elbow intradose).
A ttachment L-13-197 Pa g e 9 of 9Scanuptoanyphysical limitationtosoundunit(SU) movement(thatis,elbow
intradose).Soundexitpointismeasuredatthepointwhere anypartofthesoundunit(SU)scansurface losescontact(thatis,edgeofweldoverlay).Scanningcontinuesuntilthesound beamsignalislost;however,this scanningareaisnotrequiredforor factoredintothelimitedscan
calculations.
Nozzle DMW Butter ElbowSSCladding FSWOLOutlineofUTEquipment (typical)Requiredexamination
volume Enclosure L-13-197 Performance Demonstration Initiative Program Performance Demonstration Qualification Summary (PDQS) No. 651 (3 pages total)
PERFORMANCE DEMONSTRATION PROGRAM Date: OS-Feb-IO
\tinDiam:
2.00 \t8l[Diam:
28.00 Material:
Austenitic MinTbick; 0.1 S '\luTbick:
\.10 Examination:
Overlay Acrrss: Dual Weld Crown Condition:
Shan Range: Roughness:>=250 ,RMS Lon!! Ranl!e Roughness;e=lJ32 Gap PerformaDce Demonstration Initiative Program Printed: J'I-Jan-lJ In Accordance with tbe PDllmplementation or Section Appendix Vlll Specific Detam of Qualifications Owner: EPRI NDE CENTER Procedure:
EPRI-WOL-PA-l; Revision:
2; Addenda: 0 PDQSNo: Procedure for Manual Phased Array Ultrasonic Examination of Weld Overlaid Similar and Dissimilar Metal Welds PDQSRrv: Date of Issue: Category:
3 3()'Jan-lJ Ovi:rlay Mao Applic:atioa:
Mmusl Ranges Demonstrated:
Hardwan: N/A AquisitioD SW TyptJlb,*:
N/A Aualysis SW TypeJRu: NlA 651 Under Sc:m:h Cnit For Entire Length of Scan Paad or J
.. . .... :. '" Performance Demonstration Initiative Program Printed: 31-JaD-IJ PROGRAM In Accordance with the PDllmplementatiou or Section XI, Appendix VIII Specific Details of Qualifications Owner: EPRI NDE CENTER Procedure:
EPRI-WOL-PA-l; Revision:
2; Addenda: 0 Procedure for Manual Phased. Array Ultrasonic Examination of Weld Overlaid Similar aod Dissimilar Metal Welds Tolerances for field applications as follows: Diamct.:r; PDQSRev: Dare of Issue: Category:
Scan AppIiratioo:
3 lo-Jan*13 Overlay Manual _ .. _--------------Hardware:
Aqnisltion SW TypelRev:
Aualysls SW TypellUv:
PIpe ommclt.:rs within a range of 0.9 tQ 1.5 times the nominal diameter demonstrated shall be considered equivalent.
l>iamerCIS gn:ater lhlDl 24 n need not be demonstrated.
ThIckness I.<mer. 0.100* can be subtracted from the minimum ovcrlay thickness demonstraled.
lipper 0.:250* can be :ulded 10 the maximum overlay lhickness demonstrated_
Comments:
Candidates qualified to earlier revisions oflhis procedure are qualified to usc this revision.
2 See procedun:
Table I llI1d Table 1 for qun1ified search unit I insmnnenl combinations and CSSCIltw variable scttinp. r\IA N/A N/A 3 For PSI axial examinations of the overlay material.
100% coverage can bec:laimcd ifthc cntiR ewnination volwm: is coyc:n:d from aI least one direction.
4 For PSI circumferential ClWIIinations or the overlay materi3l.
100% COVCI1lgl:
can be c:laimcd if the* entire examination volume is covered from two directions.
5 For lSI examinations.
100% percent coverage may be claimed When the reqllin:d volume is examined from 2 directions in both the eire. and axial scan directions.
6 For lSI examinations of component diameters:!
4" (pre-ovcrtay).
examination coYenJge may be claimed when the required volume is examined Ylith angles:i!
25°. 7 For lSI ell:aminations of component diameters
< 4" (pre-overtay).
examinalion coverage rna)' be claimed when Ihe required \"Olume is examined with angles O! 45°. 8 The Appendix VID demonstration requimnents applicable to this procedure dt) nOI conlain provisions to demonstrate sizing ofaxial fJnws. \\'ben required, the tcchniquC$
described for flaw Sizing shall be used for axial Raw sizing. 651 I.imitations:
1 This proc.:dure/candidale is nol qualified for establishing the through waD dimension of flows contained within the weld overlay material.
lIowen:r.
the ligament abov!: a l1a\\ tip b qualified.
2 This procedurclcandidate is nol qualitied for detc:clion.
length or depth sizing oftlaws contained Ylithin the: base material of stainless steel I'£RFORMA.'E DEMONSTRATION PROGRAM Performance Demonstration Initiative Program In Aeeonlance with the PDllmplementation of Section Xl, Appendix Vlll Specific Details of Qualifications Owner: EPRI NDE CENTER Procedure:
EPRI-WOL-PA-l; Revision:
2; Addenda: 0 JI-Jao-lJ PDQSNo: 651 Proeedure ror Manual Phased Array Ultrasonic Examination or Weld Overlaid Similar and Dissimilar Melal Welds PDQSRtv: .} Hardware:
N/A Date or Issor: JO-JIIII-1J AqoisilioD SW l\!:A Catqtory:
Overlay Allalysis SW NiA Scaa Applieatiou:
Manual The above procedure bas met the requirements of The Performance Demonstration lnitiative 1 s Implementation or The Ameriean Society of Mechanical Engineers Boiler and Pressure Vessel Code, SeetioD XI, Appendix Vnl, as stated in this document -------
Jo gevin Perro aace Demonstration Initiative Piping SupervisorlLevellll
' ___________________
_
Performance Demonstration Initiative Piping Projed Manager PllgeJor 3 Date: J &\,.:l!3