[Federal Register Volume 75, Number 22 (Wednesday, February 3, 2010)]
[Rules and Regulations]
[Pages 5495-5498]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-2283]
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NUCLEAR REGULATORY COMMISSION
10 CFR Part 50
RIN 3150-AI01
[NRC-2007-0008]
Alternate Fracture Toughness Requirements for Protection Against
Pressurized Thermal Shock Events; Correction
AGENCY: Nuclear Regulatory Commission.
ACTION: Final rule; correction.
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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:
Sec. 50.61a [Corrected]
0
1. On page 27, paragraph (g) of Sec. 50.61a is corrected to read as
follows:
(g) Equations and variables used in this section.
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[GRAPHIC] [TIFF OMITTED] TR03FE10.005
[GRAPHIC] [TIFF OMITTED] TR03FE10.006
where:
P [wt-&%] = phosphorus content
Mn [wt-%] = manganese content
Ni [wt-%] = nickel content
Cu [wt-%] = copper content
A = 1.140 x 10-7 for forgings
A = 1.451 x 10-7 for plates
A = 1.417 x 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
[phis]te = [phis]t for [phis] >= 4.39 x 10\10\ n/cm\2\/sec
[phis]te = [phis]t x (4.39 x 10\10\/[phis])\0.2595\ for
[phis] < 4.39 x 10\10\ n/cm\2\/sec
where:
[phis] [n/cm\2\/sec] = average neutron flux
t [sec] = time that the reactor has been in full power operation
[phis]t [n/cm\2\] = [phis] x 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 x (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,[phis]te) = 0.5 + (0.5 x tanh
{[log10([phis]te) + (1.1390 x Cue)-
(0.448 x Ni)-18.120]/0.629{time}
Equation 8: Residual (r) = measured [Delta]T30-predicted
[Delta]T30 (by Equations 5, 6 and 7)
[GRAPHIC] [TIFF OMITTED] TR03FE10.007
Equation 10: Maximum credible heat-average residual = 2.33[sigma]/
n\0.5\
where:where:
n = number of surveillance data points (sample size) in the specific
data set
[sigma] = standard deviation of the residuals about the model for a
relevant material group given in Table 5.
[GRAPHIC] [TIFF OMITTED] TR03FE10.008
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.
[GRAPHIC] [TIFF OMITTED] TR03FE10.009
where:
r is defined using Equation 8 and [sigma] is given in Table 5
Table 1--PTS Screening Criteria
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RTMAX X limits [[deg]F] for different vessel wall
thicknesses \6\ (TWALL)
Product form and RTMAX X values --------------------------------------------------------
9.5 in. < TWALL 10.5 in. < TWALL
TWALL <= 9.5 in. <= 10.5 in. <= 11.5 in.
----------------------------------------------------------------------------------------------------------------
Axial Weld--RTMAX AW................................... 269 230 222
Plate--RTMAX PL........................................ 356 305 293
Forging without underclad cracks--RTMAX FO \7\......... 356 305 293
Axial Weld and Plate--RTMAX AW + RTMAX PL.............. 538 476 445
Circumferential Weld--RTMAX CW \8\..................... 312 277 269
Forging with underclad cracks--RTMAX FO \9\............ 246 241 239
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\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\ RTPTS limits contribute 1x10-8 per reactor year to the reactor vessel TWCF.
[[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
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Through-wall extent, TWE [in.] Maximum number of
--------------------------------------------------- flaws per 1,000-
inches of weld
length in the
inspection volume
TWEMIN TWEMAX that are greater
than or equal to
TWEMIN and less than
TWEMAX
------------------------------------------------------------------------
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.
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Table 3--Allowable Number of Flaws in Plates and Forgings
------------------------------------------------------------------------
Through[dash]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
TWEMIN TWEMAX equal to TWEMIN and
less than TWEMAX.
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.
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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 [[deg]F] for Relevant Material Groups by Number of Available Data Points
(Significance Level = 1%)
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Number of available data points
Material group [sigma] -----------------------------------------------------------------
[[deg]F] 3 4 5 6 7 8
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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 <= 18.6 25.0 21.7 19.4 17.7 16.4 15.3
0.072.............................
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Table 6--TMAX Values for the Slope Deviation Test (Significance Level =
1%)
------------------------------------------------------------------------
Number of available data points (n) TMAX
------------------------------------------------------------------------
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
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Dated at Rockville, Maryland, this 29th day of January 2010.
[[Page 5498]]
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]
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