Figures I.7 and I.8 present plots of these RPV base cases, compared to the piping base cases from Appendices D, E, F, and G. For purposes of this comparison, a single set of piping base case LOCA frequencies were derived that are a composite of the results from the four appendices. Plots are presented for the 0-25 year (Figure I.7) and the 25-40 year (Figure I.8) periods. Since the RPV LOCA frequencies for the 40-60 year period are not significantly different than the 25-40 year results, a separate plot for that case is not included. It is seen from these figures that the RPV base cases are at the low end of the piping

LOCA probabilities for the large break Categories 5 and 6, but are at the high end for small, Category 1 and 2 breaks, due largely to the small penetration (CRDM) contributions discussed above. Note also that the small LOCA probability estimates are substantially lower in the outlying years (25-40 and 40-60) because of inspection programs implemented as a result of these issues. In general, small break LOCA frequency contributors (Categories 1 and 2) from PWR RPVs are seen to be greater than those for BWRs, due to the PWSCC concern in CRDM and other small penetrations. Large break LOCA contributors (Categories 5 and 6) are also estimated to be greater for PWR RPVs due to higher irradiation embrittlement and the potential for PTS transients.

I-7

Break				Average LOCA Probabilities
Cat.	Break	Size		During Operating	Years:
	gpm	NPS	0-25 yrs	25-40 yrs	40-60 yrs
				TimeFactor	TimeFactor
1	100	0.5	1.00E-08	2.98E-08 2.98	4.57E-08	4.57
2	1,500	1.5	2.32E-09	6.19E-09 2.67	2.84E-08	12.24
3	5,000	3.5	1.21E-09	3.12E-09 2.58	2.30E-08	19.01
4	25,000	7	5.04E-10	1.25E-09 2.47	1.73E-08	34.33
5	100,000	16	2.38E-10	5.65E-10 2.37	1.36E-08	57.14
6	500,000	30	9.86E-11	2.32E-10 2.35	1.02E-08	103.45
			BWR FW Nozzles
Break				Average LOCA Probabilities
Cat.	Break	Size		during Operating	Years:
	gpm	NPS	0-25 yrs	25-40 yrs	40-60 yrs
				TimeFactor	TimeFactor
1	100	0.5	1.00E-06	1.47E-06 1.47	1.25E-06	1.25
2	1,500	1.5	2.00E-07	2.94E-07 1.47	2.50E-07	1.25
3	5,000	3.5	4.00E-08	5.88E-08 1.47	5.00E-08	1.25
4	25,000	7	8.00E-09	1.18E-08 1.47	1.00E-08	1.25
5	100,000	16
6	500,000	30
		BWR CRDs & Other Small Penetrations
Break				Average LOCA Probabilities
Cat.	Break	Size		during Operating	Years:
	gpm	NPS	0-25 yrs	25-40 yrs	40-60 yrs
0			2.00E-03	5.00E-04 Factor	5.00E-04 Factor
1	100	0.5	1.27E-04	2.75E-05 0.22	2.75E-05	0.22
2	1,500	1.5	2.50E-05	5.00E-06 0.20	5.00E-06	0.20
3	5,000	3.5	4.00E-09	2.00E-10 0.05	2.00E-10	0.05
4	25,000	7
5	100,000	16
6	500,000	30
			BWR Vessel — Totals
Break				Average LOCA Probabilities
Cat.	Break	Size		during Operating	Years:
	gpm	NPS	0-25 yrs	25-40 yrs	40-60 yrs
				TimeFactor	TimeFactor
1	100	0.5	1.28E-04	2.90E-05 0.23	2.88E-05	0.23
2	1,500	1.5	2.52E-05	5.30E-06 0.21	5.28E-06	0.21
3	5,000	3.5	4.52E-08	6.21E-08 1.37	7.32E-08	1.62
4	25,000	7	8.50E-09	1.30E-08 1.53	2.73E-08	3.21
5	100,000	16	2.38E-10	5.65E-10 2.37	1.36E-08	57.14
6	500,000	30	9.86E-11	2.32E-10 2.35	1.02E-08	103.45

Break Cat.		Break Size		Pete Riccardella Estimate
		gpm	NPS	0-25 yrs	25-40 yrs		40-60 yrs
						Factor		Factor
	1	100	0.5	1.00E-07	2.98E-07		2.98	4.57E-07	4.57
	2	1,500	1.5	2.32E-08	6.19E-08		2.67	2.84E-07	12.24
	3	5,000	3	1.21E-08	3.12E-08		2.58	2.30E-07	19.01
	4	25,000	7	5.04E-09	1.25E-08		2.47	1.73E-07	34.33
	5	100,000	14	2.38E-09	5.65E-09		2.37	1.36E-07	57.14
	6	500,000	30	9.86E-10	2.32E-09		2.35	1.02E-07	103.45
				PWR CRDMs
Break Cat.		Break Size		Pete Riccardella Estimate
		gpm	NPS	0-25 yrs	25-40 yrs		40-60	yrs
	0			2.00E-02	5.00E-03	Factor	5.00E-03	Factor
	1	100	0.5	1.27E-03	2.75E-04		0.22	2.75E-04	0.22
	2	1,500	1.5	2.50E-04	5.00E-05		0.20	5.00E-05	0.20
	3	5,000	3.5	4.00E-08	2.00E-09		0.05	2.00E-09	0.05
	4	25,000	7
	5	100,000	16
	6	500,000	30
				PWR Vessel	— Totals
Break Cat.		Break Size		Pete Riccardella Estimate
		gpm	NPS	0-25 yrs	25-40 yrs		40-60	yrs
						Factor		Factor
	1	100	0.5	1.27E-03	2.75E-04		0.22	2.76E-04	0.22
	2	1,500	1.5	2.50E-04	5.01E-05		0.20	5.03E-05	0.20
	3	5,000	3.5	5.21E-08	3.32E-08		0.64	2.32E-07	4.45
	4	25,000	7	5.04E-09	1.25E-08		2.47	1.73E-07	34.33
	5	100,000	16	2.38E-09	5.65E-09		2.37	1.36E-07	57.14
	6	500,000	30	9.86E-10	2.32E-09		2.35	1.02E-07	103.45

I.6 References

1.1 Peter Riccardella, Nathaniel Cofie, Angah Miessi, Stan Tang, Bryan Templeton, “Probabilistic Fracture Mechanics Analysis to Support Inspection Intervals for RPV Top Head Nozzles” U. S. Nuclear Regulatory Commission / Argonne National Laboratory Conference on Vessel Head Penetration Inspection, Cracking, and Repairs, September 29 — October 2, 2003, Gaithersburg, Maryland.

1.2 Materials Reliability Program, MRP-105, “Probabilistic Fracture Mechanics Analysis of PWR Reactor Pressure Vessel Top Head Nozzle Cracking,” EPRI Report 1007834 (EPRI Licensed Material), May, 2004.

1.3 EPRI Report, “BWR Reactor Pressure Vessel Shell Weld Inspection Recommendations (BWRVIP — 05),” TR-105697, September 1995.

1.4 NRC Report, “Final Safety Evaluation of the BWR Vessel and Internals Project BWRVIP-05 Report (TAC No. M93925),” Division of Engineering, Office of Nuclear Reactor Regulation, May 1998.

1.5 NUREG-0619, “BWR Feedwater Nozzle and CRD Return Line Nozzle Cracking, Resolution of Generic Tech Activity A-10,” November 1980.

1.6 U. S. NRC Order EA-03-009, “Interim Inspection Requirements for Reactor Pressure Vessel Heads at Pressurized Water Reactors”, issued on February 11, 2003.

1.7 VIPER Version 1.2, Structural Integrity Associates, Report # SIR-95-098 Rev. 1, Feb. 1999.

0.90
0.63 0.50
0.20
0.10
0.05
0.02
0.01
1	10	100
EDYs

Figure I.1 Weibull Plot of Plant Inspection Data Showing Extrapolation Back to Time of First Leakage or Cracking. Plants that Performed NDE and were Found Clean are

Treated as Suspensions

1.00E-01

Figure I.2 Benchmarking of PFM Crack Growth Analyses with Respect to Field-Observed

Circumferential Cracking of Various Lengths

2.0E-03
0.0E+00
10 15 20 25 Operating Years
30	35	40
5

0

Figure I.3 RPV Top Head PFM Analysis Results for Plant with 580°F (304°C) Head Temperature — Probability of CRDM Nozzle Failure (i. e. Ejection of Nozzle from Vessel Head)

Figure I.4 RPV Top Head PFM Analysis Results for Plant with 580°F (304°C) Head Temperature —

Probability of Leakage from CRDM Nozzle

Figure I.5 Schematic of Thermal Fatigue Cracking in BWR Feedwater Nozzles

Figure I.6 Historical BWR Feedwater Nozzle Cracking Experience (circa 1980)

‘ *100000 A ‘F — .

1.00E-04
1.00E-05
1.00E-08
1.00E-09
1500	5000	25000	500000
1.00E-10

Break Size (G PM)

Figure I.7 Comparison of RPV and Piping Base Case LOCA Frequencies Versus Break Size

(0 to 25 Years)

Figure I.8 Comparison of RPV and Piping Base Case LOCA Frequencies Versus Break Size

(25 to 40 Years)