ML103500484

Lr - Teleconference to Discuss SAMA Clarification RAIs

ML103500484
Person / Time
Site:	Diablo Canyon
Issue date:	12/16/2010
From:	Office of Nuclear Reactor Regulation
To:	Division of License Renewal
References
Download: ML103500484 (3)

Text

DiabloCanyonNPEm Resource From: Stuyvenberg, Andrew Sent: Thursday, December 16, 2010 3:13 PM To: dngd@pge.com Cc: DiabloCanyonNPEm Resource; Tan, Miranda; Grebel, Terence

Subject:

Teleconference to discuss SAMA Clarification RAIs Importance: High Dan -

As I mentioned earlier today, Ive received a request from our SAMA reviewers for a teleconference regarding the SAMA clarification responses we recently received. Their particular informational needs are detailed in items 1 through 6, below.

Our staff is available on a limited basis next week. Were available from 2p to 5p (EST) on Monday, and from 1p to 2p (EST) on Tuesday. Ill be traveling on Wednesday, but I may also be able to coordinate a call on Wednesday afternoon (again, after 1p EST) if that would work for you all. Our reviewers will not be available again until after the first of the year. We anticipate that well need one hour for the call.

Please call me (301-415-4006) if you have any questions, and I look forward to hearing from you.

Best, Drew

1. The responses to a number of RAIs state that the DC01B model includes or does certain things or gives certain results. Presumably these statements are also true for the DC01A model since the only difference between the two models is the seismic hazard curve.

2. The response to RAI 4 (or RAI 1.i) mentions that the DC00 (stage 1) model was modified to take credit for RCS depressurization following loss of charging in the seismic PRA and this resulted in a reduction in total CDF to 5.05E-5 per year. Was this change incorporated in the DCC0 model? The results for DCC0 do not show such a significant decrease in CDF.

3. RAI 8 (or RAI 2.e and 2.d). The RAI response does not support the conclusion that the higher cesium (Cs) release fraction for RC16U than for RC14 would not be expected to impact the consequences by a significant amount. Consider that the RC16U/RC14 Cs release fraction ratio, derived from information provided in ER Table F.2-8, is 2.9 (4.3E-02/1.5E-02) for the MAAP3 results and 1.7 (8.9E-02/5.1E/-02) for the ZISOR results, while the release frequency ratio, derived from information provided in the response to RAI 2.b, is 0.7 (5.98E-07/8.55E-07). The NRC staff performed an analysis that scaled the population dose-risk and OECR for the ST2 release category by the MAAP3 ratio. The NRC staffs analysis showed that SAMA 3, and potentially SAMAs 10 and 18, were potentially cost-beneficial, in addition to the SAMAs previously determined by PG&E to be cost-beneficial. Provide further justification for the conclusion in the RAI 8 response that the difference in the Cs release fractions for RC16U and RC14 would not impact the results of the SAMA analysis.

4. The response to RAI 10 (or RAI 2.j) discusses some mitigation actions called for in the SAMGs. To what extent are the SAMGs incorporated into the DCPP Level 2 model?

5. RAI 11 (or RAi 3.c). SAMAs 5 and 18 are described as identical except that the alternate EDG is seismically qualified in SAMA 18. How does split fraction TD2 differ from TD1 and TDF?

1

6. RAI 12 (or RAI 3.d). Are AFW seismic failures in the sequence therefore failures or unavailabilities of the AFW water sources?

Drew Stuyvenberg U.S. Nuclear Regulatory Commission 3014154006 Andrew.Stuyvenberg@nrc.gov 2

Hearing Identifier: DiabloCanyon_LicenseRenewal_NonPublic Email Number: 2310 Mail Envelope Properties (AF843158D8D87443918BD3AA953ABF781C556BC226)

Subject:

Teleconference to discuss SAMA Clarification RAIs Sent Date: 12/16/2010 3:13:15 PM Received Date: 12/16/2010 3:13:17 PM From: Stuyvenberg, Andrew Created By: Andrew.Stuyvenberg@nrc.gov Recipients:

"DiabloCanyonNPEm Resource" <DiabloCanyonNPEm.Resource@nrc.gov>

Tracking Status: None "Tan, Miranda" <M1TF@pge.com>

Tracking Status: None "Grebel, Terence" <TLG1@pge.com>

Tracking Status: None "dngd@pge.com" <dngd@pge.com>

Tracking Status: None Post Office: HQCLSTR02.nrc.gov Files Size Date & Time MESSAGE 3226 12/16/2010 3:13:17 PM Options Priority: High Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received: