SCE: Gambling Our Future On Probabilities & Un-Verified Data

PRESS RELEASE 

The DAB Safety Team: November 30, 2012

Media Contact: Don Leichtling (619) 296-9928 or Ace Hoffman (760) 720-7261 

Don't Gamble Our Future On Probabilities & Un-Verified Data

SCE erroneous claims about Westinghouse and AREVA Operational Analysis (OA) as being Deterministic Analysis are misleading, confusing and controversial.  These OA’s are Actually Possibilistic Analysis, (PA) which is nothing more than Profitganda, the use of phony "feel good" information to sell an idea, product or concept to the masses.

Safety analysis can be characterized as Probabilistic, Deterministic or a combination of both known as Possibilistic Analysis.  Deterministic Analysis Definition: Analysis of a deterministic problem, without taking the probabilities of different event sequences into account. [Source: Businessdictionary.com]

1.     Attachment 6 - Steam Generator Operational Assessment- 3.6 Summary of All OAs  - The OAs (See Table 3-1) summarized in Sections 3.1 and 3.2 conclude the SIPC and AILPC are satisfied.

Table 3-1: Edison OA Approach and Results Comparison

OA Description	OA for Degradation Mechanisms Other Than TTW	TTW OA With No Effective AVB Supports	“Traditional” Probabilistic OA Prepared for TTW	Deterministic TTW OA
Reference Attachment 6 Appendix	Appendix A AREVA	Appendix B AREVA	Appendix C Intertek APTECH	Appendix D Westinghouse
Edison Claim	Probabilistic	Deterministic	Probabilistic	Deterministic
DAB Safety Team Analysis	Probabilistic	Possibilistic (Alarming)	Probabilistic	Possibilistic (Alarming)

2.  AREVA Attachment 6 – Appendix B: SONGS U2C17 - Steam Generator Operational Assessment for Tube-to-Tube Wear – page 20 - 4.2 - Operational Assessment Strategy: The nominal distance between extrados and intrados locations of neighboring U-bends in the same plane ranges from 0.25 inches to 0.325 inches due to the tube indexing. There are 36 U-bends in Unit 2 SG E-088 and 34 in SG E-089 with a separation less than or equal to 0.050 inches (Design 0.25 inches, Arkansans Nuclear One Unit 2 0.35-0.50 inches).  The U-bends with the smaller separation distances are much better candidates for wear by rubbing yet do not exhibit TTW.  Contact forces, as deteriorated by tube wear at support locations over time, will be calculated using advanced computational techniques. This will be combined with calculations of stability ratios to develop the probability of the onset of in-plane fluid-elastic instability (an alarming statement because a Main Steam Line Break (MSLB) accident has no time line), both as a function of operating power level and operating time. The operating power and operating time will be adjusted to provide a probability of occurrence of instability 0.05. This probability is based on considerations and requirements described in the EPRI SG Integrity Assessment Guidelines. Without the development of TTW, the Structural Integrity Performance Criteria, SIPC, is automatically satisfied to a probability greater than 0.95.

DAB Safety team Comment:  This is claimed to be a Deterministic OA but is using Probabilities. This is projecting possibilities using probabilities.  Hence this is an (Alarming) Possibilistic OA and not a Deterministic OA as claimed by SCE.

 3. Westinghouse Attachment 6 – Appendix D: Operational Assessment of Wear Indications In the U-bend Region of San Onofre Unit 2 Replacement Steam Generators, Page 5, Section 1- Introduction: For the SONGS application, the resulting wear distribution after a cycle of operation is known, or can be inferred from existing ECT data, but for any given tube, there are many parameters that resulted in the wear distribution that are unknown.  It can be assumed that the tube and AVB surfaces will not have significant run-in effects for the first cycle of operation, but even this assumption involves a potential error of several hundred percent. Most importantly, the tube/AVB geometry is expected to be different than the original design intent, but all that can be inferred with the available information is the minimum length of the dominant tube vibration span. In the largest sense, the answer (wear distribution) is known, but the inputs are unknown.

Foot Note 4, Page 101: Westinghouse does not have access to the assembly procedures. The 0.12 to 0.14 dimensions are anecdotal without verification.  NOTE: Anecdotal: Based on personal observation, case study reports, or random investigations rather than systematic scientific evaluation. [Source: dictionary.reference.com]

Foot Note 5, Page 102: Westinghouse does not have access to final manufacturing or inspection details, but anecdotal input indicates that six-pound weights were allowed and used during AVB inspection for consistency with AVB drawing tolerances.

DAB Safety team Comment:  When you start using the words unknown, assumed, inputs are unknown, anecdotal without verification and this assumption involves a potential error of several hundred percent, then this Deterministic OA is using unknown Probabilities and un-validated (Alarming) Possibilities. Hence this is a Possibilistic OA and not a Deterministic OA as claimed by Edison.

4. Enclosure 2 San Onofre Nuclear Generating Station Unit 2 Return to Service Report -Section 5.2.2 Probabilistic Risk Assessment: The differential pressure across the SG tubes necessary to cause a rupture will not occur if operators prevent RCS re-pressurization in accordance with Emergency Operating Instructions.

The DAB Safety Team Comment:  Do Southern Californians really want to live at the mercy of SCE’s plant operators, who will be put in the very difficult position of operating defective steam generators that already have thousands of damaged tubes, just so SCE can profit (See SONGS Union Leader's letter that the SONGS workforce thinks a restart is not safe)?  Even an Ex-Plant Shift Manager said, “He was not going to put his license on line and risk public lives because SCE Management wants to make money by restarting a defective reactor.”  The question is, how bad do these steam generators have to be before the NRC tells SCE to pulls the plug? 

The DAB Safety Team believes that SCE’s own data proves beyond a doubt, that these already heavily damaged replacement steam generators (RSG) should never be restarted.

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Copyright November 30, 2012 by The DAB Safety Team.  All rights reserved. This material may not be published, broadcast or redistributed without crediting the DAB Safety Team. The contents cannot be altered without the Written Permission of the DAB Safety Team Leader and/or the DAB Safety Team’s Attorneys.