Rules and Regulations. Final rule; correction

Agency: Nuclear Regulatory Commission
Action: Final rule; correction
Citation: FR Doc. 2010-2283 · RIN 3150-AI01 · NRC-2007-0008 · 10 CFR 50

Summary

This document corrects a rule that appeared in the Federal Register on January 4, 2010 (75 FR 13), that amends the NRC's regulations to provide alternate fracture toughness requirements for protection against pressurized thermal shock (PTS) events for pressurized water reactor (PWR) pressure vessels. This document is necessary to correct formatting and typographical errors in paragraph (g).

Dates

The correction is effective February 3, 2010, the date the original rule becomes effective.

Supplementary Information

In FR doc. E9-31146, published on January 4, 2010, make the following correction: § 50.61a [Corrected] 1. On page 27, paragraph (g) of § 50.61a is corrected to read as follows: (g) Equations and variables used in this section. ER03FE10.000 ER03FE10.001 ER03FE10.002 ER03FE10.003 ER03FE10.004 ER03FE10.005 ER03FE10.006 where: P [wt-&%] = phosphorus content Mn [wt-%] = manganese content Ni [wt-%] = nickel content Cu [wt-%] = copper content A = 1.140 × 10 −7 for forgings A = 1.451 × 10 −7 for plates A = 1.417 × 10 −7 for welds B = 102.3 for forgings B = 102.5 for plates in non-Combustion Engineering manufactured vessels B = 135.2 for plates in Combustion Engineering vessels B = 155.0 for welds φt ^e = φt for φ ≥ 4.39 × 10 10 n/cm 2 /sec φt ^e = φt × (4.39 × 10 10 /φ) 0.2595 for φ < 4.39 × 10 10 n/cm 2 /sec where: φ [n/cm 2 /sec] = average neutron flux t [sec] = time that the reactor has been in full power operation φt [n/cm 2 ] = φ × t f(Cu ^e ,P) = 0 for Cu ≤ 0.072 f(Cu ^e ,P) = [Cu ^e −0.072] 0.668 for Cu > 0.072 and P ≤ 0.008 f(Cu ^e ,P) = [Cu ^e −0.072 + 1.359 × (P−0.008)] 0.668 for Cu > 0.072 and P > 0.008 where: Cu ^e = 0 for Cu ≤ 0.072 Cu ^e = MIN (Cu, maximum Cu ^e ) for Cu > 0.072 maximum Cu ^e = 0.243 for Linde 80 welds maximum Cu ^e = 0.301 for all other materials g(Cu ^e ,Ni,φt ^e ) = 0.5 + (0.5 × tanh {[log ¹⁰ (φt ^e ) + (1.1390 × Cu ^e )−(0.448 × Ni)−18.120]/0.629} Equation 8: Residual (r) = measured ΔT ³⁰ −predicted ΔT ³⁰ (by Equations 5, 6 and 7) ER03FE10.007 Equation 10: Maximum credible heat-average residual = 2.33σ/n 0.5 where: where: n = number of surveillance data points (sample size) in the specific data set σ = standard deviation of the residuals about the model for a relevant material group given in Table 5. ER03FE10.008 where: m is the slope of a plot of all of the r values (estimated using Equation 8) versus the base 10 logarithm of the neutron fluence for each r value. The slope shall be estimated using the method of least squares. se(m) is the least squares estimate of the standard-error associated with the estimated slope value m. ER03FE10.009 where: r is defined using Equation 8 and σ is given in Table 5 Table 1—PTS Screening Criteria Product form and RT ^MAX-X values RT ^MAX-X limits [°F] for different vessel wall thicknesses 6 (T ^WALL ) T ^WALL ≤ 9.5 in. 9.5 in. < T ^WALL ≤ 10.5 in. 10.5 in. < T ^WALL ≤ 11.5 in. Axial Weld—RT ^MAX-AW 269 230 222 Plate—RT ^MAX-PL 356 305 293 Forging without underclad cracks—RT ^MAX-FO 7 356 305 293 Axial Weld and Plate—RT ^MAX-AW + RT ^MAX-PL 538 476 445 Circumferential Weld—RT ^MAX-CW 8 312 277 269 Forging with underclad cracks—RT ^MAX-FO 9 246 241 239 6 Wall thickness is the beltline wall thickness including the clad thickness. 7 Forgings without underclad cracks apply to forgings for which no underclad cracks have been detected and that were fabricated in accordance with Regulatory Guide 1.43. 8 RT ^PTS limits contribute 1×10 −8 per reactor year to the reactor vessel TWCF. 9 Forgings with underclad cracks apply to forgings that have detected underclad cracking or were not fabricated in accordance with Regulatory Guide 1.43. Table 2—Allowable Number of Flaws in Welds Through-wall extent, TWE [in.] TWE ^MIN TWE ^MAX Maximum number of flaws per 1,000-inches of weld length in the inspection volume that are greater than or equal to TWE ^MIN and less than TWE ^MAX 0 0.075 No Limit. 0.075 0.475 166.70. 0.125 0.475 90.80. 0.175 0.475 22.82. 0.225 0.475 8.66. 0.275 0.475 4.01. 0.325 0.475 3.01. 0.375 0.475 1.49. 0.425 0.475 1.00. 0.475 Infinite 0.00. Table 3—Allowable Number of Flaws in Plates and Forgings Through-wall extent, TWE [in.] TWE ^MIN TWE ^MAX Maximum number of flaws per 1,000 square-inches of inside surface area in the inspection volume that are greater than or equal to TWE ^MIN and less than TWE ^MAX . This flaw density does not include underclad cracks in forgings 0 0.075 No Limit. 0.075 0.375 8.05. 0.125 0.375 3.15. 0.175 0.375 0.85. 0.225 0.375 0.29. 0.275 0.375 0.08. 0.325 0.375 0.01. 0.375 Infinite 0.00. Table 4—Conservative Estimates for Chemical Element Weight Percentages Materials P Mn Plates 0.014 1.45 Forgings 0.016 1.11 Welds 0.019 1.63 Table 5—Maximum Heat-Average Residual [°F] for Relevant Material Groups by Number of Available Data Points (Significance Level = 1%) Material group σ [°F] Number of available data points 3 4 5 6 7 8 Welds, for Cu > 0.072 26.4 35.5 30.8 27.5 25.1 23.2 21.7 Plates, for Cu > 0.072 21.2 28.5 24.7 22.1 20.2 18.7 17.5 Forgings, for Cu > 0.072 19.6 26.4 22.8 20.4 18.6 17.3 16.1 Weld, Plate or Forging, for Cu ≤ 0.072 18.6 25.0 21.7 19.4 17.7 16.4 15.3 Table 6—T ^MAX Values for the Slope Deviation Test (Significance Level = 1%) Number of available data points (n) T ^MAX 3 31.82 4 6.96 5 4.54 6 3.75 7 3.36 8 3.14 9 3.00 10 2.90 11 2.82 12 2.76 13 2.72 14 2.68 15 2.65 Dated at Rockville, Maryland, this 29th day of January 2010. For the Nuclear Regulatory Commission. Michael T. Lesar, Chief, Rulemaking and Directives Branch, Division of Administrative Services, Office of Administration. [FR Doc. 2010-2283 Filed 2-2-10; 8:45 am]