DCL-14-093, Revision to Response Date for NRC Request for Additional Information - Fire Modeling 3 - National Fire Protection Association Standard 805
| ML14300A706 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 10/27/2014 |
| From: | Allen B Pacific Gas & Electric Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| DCL-14-093 | |
| Download: ML14300A706 (3) | |
Text
Pacific Gas and Electric Company October 27, 2014 PG&E Letter DCL-14-093 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Diablo Canyon Units 1 and 2 Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Barry S. Allen Site Vice President Diablo Canyon Power Plant Mail Code 104/6 P. 0. Box 56 Avila Beach, CA 93424 805.545.4888 Internal: 691.4888 Fax: 805.545.6445 10 CFR 50.90 Revision to Response Date for NRC Request for Additional Information-Fire
. Modeling 3 - National Fire Protection Association Standard 805
Reference:
- 1. NRC Letter, "Diablo Canyon Power Plant, Units 1 and 2 - Request for Additional Information Re: License Amendment Request to Adopt National Fire Protection Association Standard 805 (TAC Nos. MF2333 and MF2334),"
dated July 31, 2014
Dear Commissioners and Staff:
In Reference 1, the NRC provided a request for additional information (RAI) regarding Pacific Gas and Electric Company's (PG&Es) license amendment request (LAR) to adopt National Fire Protection Association Standard 805. The RAI questions were discussed in draft form in a teleconference on July 8, 2014, and during an audit performed at Diablo Canyon Power Plant during the week of July 14-18, 2014.
On October 16, 2014, PG&E discussed with NRC Staff moving the response to Fire Modeling (FM) RAI 3.b from the 90-day response letter to the 120-day response letter. PG&E agreed to provide the reason for changing the response date in a letter.
The reason for the change in the response date is as follows:
The only fire modeling tool used that was not explicitly listed in Attachment J of the LAR is Consolidated Model of Fire and Smoke Transport (CFAST).
CFAST was used to analyze the hot gas layer (HGL) for a catastrophic turbine generator (TG) fire within fire zones 14-D and 19-D. CFAST was also used to model thermocouple targets at critical locations to analyze the A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway
- Comanche Peak
- Diablo Canyon
- Palo Verde
- Wolf Creek
m Document Control Desk r!if&~ October 27, 2014 Page 2 temperature where structural steel is exposed.
PG&E Letter DCL-14-093 The verification and validation (V&V) basis for HGL calculations using CFAST was provided in the LAR. The V&V basis for thermocouple targets was not provided in the LAR.
During review of the V&V basis for the use of thermocouple targets in CFAST, one of the limitations of CFAST (specifically flame height to ceiling height ratio) was identified as being outside the range of limitation for CFAST V&V.
In order to properly address the concern, PG&E elected to use Fire Dynamics Simulator (FDS) as a FM tool to perform a sensitivity analysis of the TG fire scenario. This analysis is a complex simulation using computational fluid dynamics FM software that requires additional time to perform. The sensitivity analysis making use of this FM tool (FDS) is not yet complete.
Consistent with other RAI responses, all subparts of FM RAI 3 will be submitted within the same RAI response letter. Therefore, PG&E will provide the response to FM RAI 3 with the other 120-day RAI responses due to the additional analysis being performed to respond to FM RAI 3.b.
PG&E makes no regulatory commitments (as defined by NEI 99-04) in this letter.
This letter includes no revisions to existing regulatory commitments.
If you have any questions or require additional information, please contact Mr. Tom Baldwin at 805-545-4720.
I state under penalty of perjury that the foregoing is true and correct.
Executed on October 27, 2014.
Sincerely,
....6~5. 4a-Barry S. Allen Site Vice President A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway
- Comanche Peak
- Diablo Canyon
- Palo Verde
- Wolf Creek
Document Control Desk October 27, 2014 PG&E Letter DCL-14-093 Page 3 mjrm/4557/50037 411 cc:
Diablo Distribution Marc L. Dapas, NRC Region IV Administrator Thomas R. Hipschman, NRC Senior Resident Inspector Eric R. Oesterle, NRC Senior Project Manager Gonzalo L. Perez, California Department of Public Health A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway
- Comanche Peak
- Diablo Canyon
- Palo Verde
- Wolf Creek