# [Corrected]
**AGENCY:**
Nuclear Regulatory Commission.
**ACTION:**
Final rule; correction.
**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.
**FOR FURTHER INFORMATION CONTACT:**
Michael T. Lesar, Chief, Rulemaking and Directives Branch, Office of Administration, Nuclear Regulatory Commission, Washington, DC 20555-0001, telephone 301-492-3663, e-mail *[email protected].*
**SUPPLEMENTARY INFORMATION:**
In FR doc. E9-31146, published on January 4, 2010, make the following correction:
§ 50.61a
1. On page 27, paragraph (g) of § 50.61a is corrected to read as follows:
(g) *Equations and variables used in this section.*
where:
P [wt-&%] = phosphorus content
Mn [wt-%] = manganese content
Ni [wt-%] = nickel content
Cu [wt-%] = copper content
A = 1.140 × 10 <sub>−7</sub> for forgings
A = 1.451 × 10 <sub>−7</sub> for plates
A = 1.417 × 10 <sub>−7</sub> 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 <sub>e</sub> = φt for φ ≥ 4.39 × 10 <sup>10</sup> n/cm <sup>2</sup> /sec
φt <sub>e</sub> = φt × (4.39 × 10 <sup>10</sup> /φ) <sup>0.2595</sup> for φ < 4.39 × 10 <sup>10</sup> n/cm <sup>2</sup> /sec
where:
φ [n/cm <sup>2</sup> /sec] = average neutron flux
t [sec] = time that the reactor has been in full power operation
φt [n/cm <sup>2</sup> ] = φ × t
f(Cu <sub>e</sub> ,P) = 0 for Cu ≤ 0.072
f(Cu <sub>e</sub> ,P) = [Cu <sub>e</sub> −0.072] <sup>0.668</sup> for Cu > 0.072 and P ≤ 0.008
f(Cu <sub>e</sub> ,P) = [Cu <sub>e</sub> −0.072 + 1.359 × (P−0.008)] <sup>0.668</sup> for Cu > 0.072 and P > 0.008
where:
Cu <sub>e</sub> = 0 for Cu ≤ 0.072
Cu <sub>e</sub> = MIN (Cu, maximum Cu <sub>e</sub> ) for Cu > 0.072
maximum Cu <sub>e</sub> = 0.243 for Linde 80 welds
maximum Cu <sub>e</sub> = 0.301 for all other materials
g(Cu <sub>e</sub> ,Ni,φt <sub>e</sub> ) = 0.5 + (0.5 × tanh {[log <sub>10</sub> (φt <sub>e</sub> ) + (1.1390 × Cu <sub>e</sub> )−(0.448 × Ni)−18.120]/0.629}
Equation 8: Residual (r) = measured ΔT <sub>30</sub> −predicted ΔT <sub>30</sub> (by Equations 5, 6 and 7)
Equation 10: Maximum credible heat-average residual = 2.33σ/n <sup>0.5</sup>
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.
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.*
where:
*r* is defined using Equation 8 and σ is given in Table 5
| Product form and RT | RT
limits [°F] for different vessel wall thicknesses
(T
) | T
≤ 9.5 in. | 9.5 in. < T | 10.5 in. < T |
| --- | --- | --- | --- | --- |
| Axial Weld—RT | 269 | 230 | 222 | |
| Plate—RT | 356 | 305 | 293 | |
| Forging without underclad cracks—RT | 356 | 305 | 293 | |
| Axial Weld and Plate—RT
+ RT | 538 | 476 | 445 | |
| Circumferential Weld—RT | 312 | 277 | 269 | |
| Forging with underclad cracks—RT | 246 | 241 | 239 | |
| Through-wall extent, TWE [in.] | TWE | TWE | Maximum number of flaws per 1,000-inches of weld length in the inspection volume that are greater than or equal to TWE
and less than TWE |
| --- | --- | --- | --- |
| 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. | |
| Through-wall extent, TWE [in.] | TWE | TWE | 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
and less than TWE
. 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. | |
| Materials | P | Mn |
| --- | --- | --- |
| Plates | 0.014 | 1.45 |
| Forgings | 0.016 | 1.11 |
| Welds | 0.019 | 1.63 |
| 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 | |
| Number of available | T |
| --- | --- |
| 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 |
For the Nuclear Regulatory Commission.
Dated at Rockville, Maryland, this 29th day of January 2010.
Michael T. Lesar,
Chief, Rulemaking and Directives Branch, Division of Administrative Services, Office of Administration.