ML020880150
| ML020880150 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 03/19/2002 |
| From: | - No Known Affiliation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| FOIA/PA-2001-0256 | |
| Download: ML020880150 (11) | |
Text
Communicating Safety Significance of IP2 Tube Failure For IP2, CCDP and LERF are close, creating confusion.
Analysis Initiating Frequency Conditional Core Large Early Release Damage Probability Frequency (LERF)
(CCDP) based on failure-to isolate and cooldown IP2 IPE for 1.3E-2/yr z8E-5 1 E-6/yr SGTR Feb. 2000 Tube 1 per year
-<1 E-6
-<1 E-6/yr Failure at IP2 NRC SDP Risk 0.5 per year 1 E-4*
5E-5/yr Assessment of (z 1 E-4/yr)
IP2 Tube Failure
- Value based on NUREG-1 150 Surry model and SPAR IP2 model
Risk Communication Initiating Event IP2 IPE SGTR Mitigation Result Safe Shutdown Large Early Release Operators fail to Isolate and Cooldown Frequency:
1.3E-2/yr
-8E-5 (Conditional CDP) 1 E-6/yr (LERF)
Risk Communication Initiating Event IP2Tube Failure (150 gpm)
Mitigation Result Safe Shutdown Large Early Release Operators fail to lisolate and Cooldown Frequency:
1 per year
<1 E-6 (Conditional CDP)
<1 E-6/yr (LERF)
Risk Communication Initiating Event SGTR >600 gpm Mitigation Result Safe Shutdown Large Early Release Operators fail to lisolate and Cooldown Frequency:
0.5 per year 1 E-4 (Conditional CDP) 0 For IP2, the CCDP and LERF are close, which creates confusion.
Number of SG Replacements vs. SG Forced Outages 25-7 I
I I
1990 1991 1992 W@
I I
I 1993 1994 1995 1996 1997 1998 1999 Plants with Replaced SGs SG-Related Forced Outages 20 15 10 5-C)I
Fraction of Repaired SG Tubes All SGs 95.4 4.6 Original SGs 93.6 Replaced SGs 99.75 6.4 0.25
PWRs with Repaired SG Tubes 22 PWRs w/ Replaced SGs 15 of 22 PWRs w/ Replaced SGs have Repaired Tubes 47 PWRs w/ Original SGs All PWRs with original SGs have had tube repairs
Rate of SG Forced Outages 30 25 TO2 0 "15 0
,,°15_
6 z a)
.10 E
1992 1994 1990 1996 1998
Rate of SG Tube Failures Indian Point 2 Palo Verde 2 1
" North Anna 1 Calhoun
/Z Ginna Prairie Island 1 Line indicates rate of 1 failure every 2.5 years.
1985 1990 1995 10 9
8 Co CU U
- 3 6 z E
7 6
5 4
3 2
1 0
1975 1980 2000
Reg. Guide 1.174 Acceptance Guidelines for Core Damage Frequency U..
4-Z\\
iO- ~
'S ~-~
~
~
.s4; 10-6 CDF*
10-4
Reg. Guide 1.174 Acceptance Guidelines for Large Early Release Frequency 411
....... *:,,N LERF0 10-6