ML12299A471
| ML12299A471 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 10/23/2012 |
| From: | Mogren T Constellation Energy Nuclear Group |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML12299A471 (7) | |
Text
Thomas Mogren Manager, Engineering Services CENG a joint venture of suEnergym-e0 R.E. Ginna Nuclear Power Plant, LLC 1503 Lake Road Ontario, New York 14519-9364 585.771.5208 Thomas.Mo-qren~cenpqllc.com October 23, 2012 U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTENTION:
SUBJECT:
Document Control Desk R.E. Ginna Nuclear Power Plant Docket No. 50-244 Response to Request for Additional Information Regarding Bottom Mounted Instrument Nozzle Flaw Evaluation (a) Letter from Mohan Thadani (NRC) to Thomas Harding (Ginna LLC), Ginna-BMI Flaw Evaluation (ME8247) (ML12228A618)
REFERENCES:
(b) Letter from Thomas Mogren (Ginna LLC) to Document Control Desk (NRC), ASME Code Section Xl Evaluation of the Bottom Mounted Instrumentation (BMI) Penetration Nozzle A86 at the R.E. Ginna Nuclear Power Plant (ML12080A141)
By letter dated August 15, 2012 (Reference a), the NRC requested additional information regarding R.E. Ginna Nuclear Power Plant, LLC's flaw evaluation based on American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code), Section Xl, IWB-3600, in accordance with the provisions of Title 10 of the Code of Federal Regulations Section 50.55a, Paragraph (g)(4), which was submitted to the NRC on March 16, 2012 (Reference b). The requested information is contained in the Enclosure.
There are no new regulatory commitments identified in this correspondence.
If you have any questions or need any other clarifying information, please contact Thomas L.
Harding, at (585) 771-5219.
Sincerely, A~~Th P1 1ý Thomas Mogren 14tj~Q1 14eSN
Document Control Desk October 23, 2012 Page 2
Enclosure:
Response to Request for Additional Information cc:
M.C. Thadani, NRC Ginna Resident Inspector, NRC W.M. Dean, NRC
ENCLOSURE Response to Request for Additional Information
Response To Request for Additional Information
- 1. The stress ratio calculated on page 3 of Attachment 1 to the submittal includes "external mechanical loads" on the BMI nozzle.
a) Confirm that the source of these loads (Reference 6 to the submittal) was Ginna specific.
b) Confirm that these loads are consistent with or bounded by the BMI penetration nozzle design loads.
Answer:
A) The source of external mechanical loads from Reference 6 (ALTRAN Report 88105-C-01) cited in Attachment 1 to the submittal is Ginna Station specific.
B) The loads are bounded by the BMI penetration nozzle design allowable loads as stated in Note 3 of Table 1 (page 2 of this attachment) obtained from Reference 6 cited in Attachment 1 to the submittal.
- 2. Identify and describe the contributions to the axial membrane and bending stress of 6.2 ksi reported on page 4 of Attachment 1 to the submittal. Alternatively provide the relevant sections of the associated report.
Answer:
The relevant portion of Reference 6 (Page 29 of ALTRAN Report 88105-C-01) cited in Attachment 1 to the submittal is provided in Table 1 (page 2 of this attachment) to identify and describe the axial force and bending moment contributions to the axial membrane and bending stress of 6.2 ksi reported on page 4 of Attachment 1 to the submittal. The resulting axial membrane and bending stress is obtained based on the nozzle geometry as follows:
Faxiai/A + MbendinglZ Where Faxiai = Axial Force = 92 lb (See Table 1 below)
Mbending = Bending Moment = 2298 in-lb (See Table 1 below)
A = Cross Sectional Area of Penetration Nozzle Z = Section Modulus of Penetration nozzle Page 1 of 4
Response To Request for Additional Information Table 1 Supplementary Information for RAI No. 1 and 2 Altran Corporation Technical Report 88105-C-0o Revision 0 ctual/Allowable( 1 ) Individual Condition Nozzle comparison( 2 )
lond.
Axial Shear Torsion Bencding 11-f i -1h%
tb Actual Allow Actual Allow Actual Allow Actual Allow Seadweight 44 100 8
200 14 10 290:
400(3)
TH (Normal) 1 200 1
50 10 30 60 1100 5
9000 3
15s 42 300 285 2000 E
19 200 21 50 41 150 1014 1300 SSE 47 300 46 100 89 200 2008 1900(3)
,.I (1)
(2)
(3)
Loads derived from technical specification, ME-251[l].
All Loads +; Cobmination From Appendix E the following RPV nOzzle. load combinations show all r be within COMBINED allowables.
iozzle loads to S.
4ond..
DW + TH Iozoral)
W + TH (LOCA)
Axial Shear Torsion (in-lIb)
ACtual Allow Bending Actual Allow Comment Actual Allow' ActualAllbw 45 49 63 92 300 10000 300 400 9
11 29 54 250 24 40 350 350 56 310 575 250 55 160 1304 300 103 210 2298*
1500 2400 1700 2300 0.K.
O.K.
- 0. K.
O-..
- HMaximum for any individual nozzle All loads from computer output CP-14 Page 2 of 4
Response To Request for Additional Information
- 3. The stress input for the evaluation was produced using the methodology of the original BMI nozzle fatigue evaluation cited as Reference 3 of Attachment 1 to the submittal.
Clarify why this original evaluation methodology is still valid despite changes made to plant operation, a power uprate, and a steam generator replacement, since the methodology was created.
Answer:
The analytical methods used to quantify loads for the projects cited in the Staff's question were not changed from the analytical methods used to quantify loads for the original BMI nozzle fatigue evaluation cited in Reference 3 of Attachment 1 to the submittal. While activities such as power uprate, steam generator replacement, or other changes in plant operation may affect the output of the analytical methods, they do not impact the analytical methods used to quantify the loads that are considered in the evaluation. As such, the analytical methods described in Reference 3 to Attachment 1 were used to quantify the loads applicable to the evaluation to reflect the changes in plant operation, steam generator replacement, and power uprate. The loads used in the evaluation documented in Attachment I of the submittal reflected the as-built condition of the plant as shown in CN-PAFM-1 1-41. (Reference 5 of Attachment 1 to the submittal).
- 4. Provide Reference 5 of Attachment 1 to the submittal.
Answer:
Reference 5 of Attachment 1 (CN-PAFM-1 1-41) to the submittal can be made available for review at the Westinghouse Nuclear Regulatory Affairs Office located in Rockville, Maryland, since this is a Westinghouse proprietary document.
- 5. Previous investigations of analogous welds, such as those for control rod guide tubes, have revealed that weld residual stresses remain significant even after heat-treatment.
a) Provide an analysis of the weld residual stresses in the location of interest.
b) Show that the analysis in Attachment 1 of the submittal bounds the weld residual stresses, or supplement Attachment 1 as necessary.
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Response To Request for Additional Information Answer:
A) Since the circumferential flaw of interest has been determined to be a fabrication related flaw and not subjected to primary water stress corrosion cracking, fatigue crack growth is the only credible crack growth mechanism.
The magnitude of welding residual stress does not impact the crack tip stress intensity factor range (AK) used in the fatigue crack growth analysis.
Only the load ratio R, which is Kmrin/Kmax, would be affected resulting in a higher load ratio. A load ratio of R=1 was conservatively used in the fatigue crack growth analysis as stated on page 6 of Attachment 1 to the submittal in order to address the impact associated with the welding residual stress.
It is therefore not necessary to determine the welding residual stress at the location of interest and the use of a load ratio R=1 would adequately address the effect of welding residual stress.
B) As stated on page 6 of Attachment 1 to the submittal, a load ratio of R=1 was conservatively used in the fatigue crack growth analysis to address the impact associated with the welding residual stress and therefore the analysis in of the submittal has adequately addressed the effect of welding residual stress.
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