ML23229A594
| ML23229A594 | |
| Person / Time | |
|---|---|
| Site: | 99902049 |
| Issue date: | 08/30/2023 |
| From: | Shurtleff C Holtec, SMR |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML23229A591 | List: |
| References | |
| 160-USNRC-059 | |
| Download: ML23229A594 (1) | |
Text
HOLTEC INTE FIDENTAL www.holtec.com www.smrllc.com SMR-160 - RPV Neutron Embrittlement Methods Date: 8/30/2023 Presented By: Clark Shurtleff SMR, LLC, A Holtec International Company Krishna P. Singh Technology Campus One Holtec Boulevard Camden, NJ 08104, USA
[Not Export Controlled]
HOLTEC INTERNATIONAL
HOLTEC INTE FIDENTAL holtec.com l smrllc.com l Page 2 Agenda
Introductions
Purpose & Outcome Discussion of neutron embrittlement methodology Discussion of planned surveillance program Questions Open Forum
HOLTEC INTE FIDENTAL holtec.com l smrllc.com l Page 3 Purpose & Outcome Purpose Provide SMRs plans to:
Use unique methodology to predict neutron embrittlement Justify use of that methodology Execute a surveillance plan to validate results Outcome Obtain feedback from NRC staff on this approach
holtec.com l smrllc.com l Page 4 Refresher from February Meeting SA-508 Grade 3 Class 2 base material, ((
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Low alloy steel weld material Cold leg/irradiation temperature ((
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Maximum estimated neutron fluence ((
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Fluence calculations based on RG 1.190 framework Flux at RPV surface ((
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Fluence for 40 years (38 EFPY) is ((
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HOLTEC INTE FIDENTAL holtec.com l smrllc.com l Page 5 Refresher from February Meeting RG 1.99 applicable for 525oF; not appropriate for SMR-160 Temperature dependence not considered Alternative industry standards:
ASTM E900 - includes a temperature-dependent term Irradiation temperatures 491 - 572oF SMR considered using this formula with a separate temperature factor EPRI - MRP-462 Considers test reactor data and adds flux term
____,,. 11T
= f (Cu, Ni, Mn, P, , T)
L.11r = f (Cu, Ni, Mn, P, , T, cp)
HOLTEC INTE FIDENTAL holtec.com l smrllc.com l Page 6 Temperature plays a significant role in the extent of neutron embrittlement Two main types of damage generally agreed upon:
Cu-rich clusters (N/A - low Cu)
Matrix damage (enhanced by solute clustering - Ni, Mn)
Matrix damage is worse at low temperature Less energy for diffusion Reduced self-annealing of damage
HOLTEC INTE FIDENTAL holtec.com l smrllc.com l Page 7 Temperature dependence in industry standards All data used by industry correlations is >480oF
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HOLTEC INTE IDENTAL holtec.com l smrllc.com l Page 8 SMR-160 Embrittlement Approach
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holtec.com l smrllc.com l Page 9 SMR-160 Embrittlement Approach
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HOLTEC INTE FIDENTAL holtec.com l smrllc.com l Page 10 Results of Design Assumptions
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holtec.com l smrllc.com l Page 11 SMR-160 Surveillance Program 10 CFR 50 App H requires surveillance program References ASTM E185-82 for most requirements ASTM E185-82 requirements are not ideal for SMR-160 Requires tracking of welds in addition to base metal Low lead factors (1-3) provide data slowly SMR intends to follow all other App H requirements
HOLTEC INTE FIDENTAL holtec.com l smrllc.com l Page 12 Considering replacing weld metal specimens with additional base metal (BM)
Specimens ASTM E185-82 Proposed BM Charpy BM Charpy Weld Charpy BM Charpy (2nd set)
BM tensile BM tensile Weld tensile BM tensile (2nd set)
Fracture toughness (some capsules)
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HOLTEC INTE FIDENTAL holtec.com l smrllc.com l Page 13 High lead factors (LF) generate data quickly ASTM E185-82 recommends LF of 1-3 E185-21 recommends LF below 5 Recommends validation method (e.g., correlation monitor) for LF > 5
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Recent NRC publication:
In practice, the testing of correlation monitor material has demonstrated variability which has limited the practical use of the data.
Japan and Germany allow LF of 10 and 12, respectively
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HOLTEC INTE FIDENTAL holtec.com l smrllc.com l Page 14 Lead Factor and Withdrawal Schedule
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HOLTEC INTE FIDENTAL holtec.com l smrllc.com l Page 15 Proposed ISP unit site Specimens (each capsule)
Units 1 & 2 BM Charpy - RPV 1 BM Charpy - RPV 2 BM tensile - RPV 1 BM tensile - RPV 2 Fracture toughness -
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holtec.com l smrllc.com l Page 16 Upper shelf energy is not a significant concern Requirements from 10 CFR 50 App G:
> 75ft-lbs @ BOL
> 50 ft-lbs @ EOL Typical BOL value for SA-508 Gr 3:
>100 ft-lbs is expected, 150 ft-lbs not uncommon Typical USE reduction for low Cu steel is <<50%
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Will be validated by surveillance data Considering adding a PO requirement that USE exceed 100 ft-lbs
HOLTEC INTE FIDENTAL holtec.com l smrllc.com l Page 17 SMR does not plan to obtain KIC data from three heats of material before construction ASME Sec XI Appendix G:
For materials with Y.S. 50-90 ksi, the existing KIC vs (T - RTNDT) design curve may be used provided fracture mechanics data are obtained on at least three heats of the material on a sufficient number of specimens to cover the temperature range of interest, including the weld metal and heat-affected zone that exceed the curve SA-508 Gr 3, Cl 2 is well known 2021 ASME code exempts it from this requirement This includes the HAZ and associated weld metals
holtec.com l smrllc.com l Page 18 BACKUP SLIDES
HOLTEC INT DENTAL holtec.com l smrllc.com l Page 19
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HOLTEC INTE FIDENTAL holtec.com l smrllc.com l Page 20
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holtec.com l smrllc.com l Page 21 MTR data compared to PWR and BWRs
- from EPRI report MTR data is conservative Flux effects from accelerated data over predict damage (ASTM E900 correlation)
Predicted - Measured AT41, [0C]
150 ----------------,----------------
100 - ----+-----+--------<~------+------+-----
-100 1-----+-----+--------<~----+------+-----t
-150 +-----..-----...------,...-----..------+-----1 8
g 10 BWR (n=342)
T 1 = 2.24 (Bias ~ *l.SC)
Figure 3-3 11 12 Log {Flux [n/cm2/sec]}
PWR (n=l,536)
T e!IJ = 0.68 (Bia5 = +0.2C) 13 14 MTR (n=562)
T8.,.5 = 10.7 IBias = -12.9C)
Data from the ASTM E10.02 PLOTTER [3] demonstrating a neutron flux effect in test reactor (MTR) AT41J values, as evidenced by the 13°C bias in the ASTM E900-15 prediction error for the MTR (purple) data
holtec.com l smrllc.com l Page 22 ASME Sec XI Appendix G - 2021 Edition (b) For materials with specified minimum yield strengths at room temperature greater than 50 ksi (350 MPa) but not exceeding 90 ksi (620 MPa), other than those in Table G-2110-1, Figure G-2210-1 (Figure G-2210-lM) may be used, pro-vided fracture mechanics data are obtained on at least three heats of the material on a sufficient number of specimens to cover the temperature range of interest, including the weld metal and heat-affected zone, and provided the data are equal to or above the curve of Figure G-2210-1 (Figure G-2210-lM). These data shall be documented. If these materials of higher yield strengths [specified minimum yield strength greater than 50 ksi (350 MPa)] but not exceeding 90 ksi (620 MPa), including the materials in Table G-2110-1, are to be used in conditions in which radiation might affect the material properties, the effect of radiation on the K 1 c curve shall be determined for the material. This information shall be documented.
Table G-2110-1 Materials With Specified Minimum Yield Strength Greater Than 50 ksi (350 MPa) But Not Exceeding 90 ksi (620 MPa) Permitted to Use Figure G-2210-1 (Figure G-2210-lM)
SA-508 Grade 2 Class 2 (former designation SA-508 Class 2A)
SA-508 Grade 3 Class 2 (former designation SA-508 Class 3A)
SA-533 Type A Class 2 (former designation SA-533 Grade A Class 2)
SA-533 TyPe B Class 2 (former designation SA-533 Grade B Class 2)