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 Nuclear Regulatory Commission 10 CFR Part 50
RIN 3150-AI01
[NRC-2007-0008]
 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 
                        *Michael.Lesar@nrc.gov.*


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 × 10−7
                         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 φte
                     = φt for φ ≥ 4.39 × 1010
                     n/cm2
                    /sec φte
                     = φt × (4.39 × 1010
                    /φ)0.2595
                     for φ < 4.39 × 1010
                     n/cm2
                    /sec where: φ [n/cm2
                        /sec] = average neutron flux t [sec] = time that the reactor has been in full power operation φt [n/cm2
                        ] = φ × t f(Cue,P) = 0 for Cu ≤ 0.072 f(Cue,P) = [Cue
                    −0.072]0.668
                     for Cu > 0.072 and P ≤ 0.008 f(Cue,P) = [Cue
                    −0.072 + 1.359 × (P−0.008)]0.668
                     for Cu > 0.072 and P > 0.008 where: Cue
                         = 0 for Cu ≤ 0.072 Cue
                         = MIN (Cu, maximum Cue) for Cu > 0.072 maximum Cue
                         = 0.243 for Linde 80 welds maximum Cue
                         = 0.301 for all other materials g(Cue,Ni,φte) = 0.5 + (0.5 × tanh {[log10
                    (φte) + (1.1390 × Cue)−(0.448 × Ni)−18.120]/0.629} Equation 8: Residual (r) = measured ΔT30
                    −predicted ΔT30
                     (by Equations 5, 6 and 7)  Equation 10: Maximum credible heat-average residual = 2.33σ/n0.5 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 Table 1—PTS Screening Criteria
Product form and RTMAX-X values
RTMAX-X
                             limits [°F] for different vessel wall thicknesses 6
                             (TWALL)TWALL
                             ≤ 9.5 in.
9.5 in. < TWALL ≤ 10.5 in.
10.5 in. < TWALL ≤ 11.5 in.Axial Weld—RTMAX-AW
269
230
222Plate—RTMAX-PL
356
305
293Forging without underclad cracks—RTMAX-FO7
356
305
293Axial Weld and Plate—RTMAX-AW
                             + RTMAX-PL
538
476
445Circumferential Weld—RTMAX-CW
                             8
312
277
269Forging with underclad cracks—RTMAX-FO
                             9
246
241
2396
                         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
                         RTPTS
                         limits contribute 1×10−8
                         per reactor year to the reactor vessel TWCF.
                        ( print page 5497)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.]
Maximum number of flaws per 1,000-inches of weld length in the inspection volume that are greater than or equal to TWEMIN
                             and less than TWEMAXTWEMIN
TWEMAX0
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.]
Maximum number of flaws per 1,000 square-inches of inside surface area in the inspection volume that are greater than or equal to TWEMIN
                             and less than TWEMAX. This flaw density does not include underclad cracks in forgingsTWEMIN
TWEMAX0
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
MnPlates
0.014
1.45Forgings
0.016
1.11Welds
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 points3
4
5
6
7
8Welds, for Cu > 0.072
26.4
35.5
30.8
27.5
25.1
23.2
21.7Plates, for Cu > 0.072
21.2
28.5
24.7
22.1
20.2
18.7
17.5Forgings, for Cu > 0.072
19.6
26.4
22.8
20.4
18.6
17.3
16.1Weld, Plate or Forging, for Cu ≤ 0.072
18.6
25.0
21.7
19.4
17.7
16.4
15.3
 Table 6—TMAX
                         Values for the Slope Deviation Test (Significance Level = 1%)
Number of available
                             data points (n)
TMAX3
31.824
6.965
4.546
3.757
3.368
3.149
3.0010
2.9011
2.8212
2.7613
2.7214
2.6815
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] BILLING CODE 7590-01-P