ML051790198
| ML051790198 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 06/17/2005 |
| From: | Mauldin D Arizona Public Service Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 102-05294-CDM/TNW/RAB | |
| Download: ML051790198 (5) | |
Text
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10 CFR 50.90 LA41:
David Mauldin Vice President Nuclear Engineering and Support Palo Verde Nuclear Generating Station Tel: 623-393-5553 Fax: 623-393-6077 Mail Station 7605 PO Box 52034 Phoenix, Arizona 85072-2034 102-05294-CDM/TNW/RAB June 17, 2005 ATTN: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001
Reference:
Letter No. 102-05116-CDMITNW/RAB, Dated July 9, 2004, from C. D.
Mauldin, APS, to U. S. Nuclear Regulatory Commission, "Request for a License Amendment to Support Replacement of Steam Generators and Uprated Power Operations in Units I and 3, and Associated Administrative Changes for Unit 2"
Dear Sirs:
Subject:
Palo Verde Nuclear Generating station (PVNGS)
Units 1, 2 and 3, Docket Nos. STN 50-528, STN 50-529 and STN 50-530 Supplement to Request for a License Amendment to Support Replacement of Steam Generators and Uprated Power Operations Concerning Reactor Drain Tank Room Hydrogen Concentration In Reference 1, Arizona Public Service Company (APS) submitted a license amendment request to support steam generator replacement and uprated power operations for PVNGS Units 1, 2 and 3. Based on a separate review of post LOCA hydrogen concentration in the containment, APS believes that Reference 1, Attachment 4, Section 9.3 requires clarification. Enclosure 2 provides the revised Section 9.3 of Reference 1 with revision bars to denote changes. This information is also applicable to Unit 2.
There are no commitments being made to the NRC in this letter.
Should you have any questions, please call Mr. Thomas N. Weber at (623) 393-5764.
Sincerely t
CDM/TNW/RAB/ca A member of the STARS (Strategic Teaming and Resource Sharing) Alliance A bbl Callaway
- Comanche Peak
- Diablo Canyon
- Palo Verde
- South Texas Project
- Wolf Creek
U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Supplement to Request for a License Amendment to Support Replacement of Steam Generators and Uprated Power Operations Concerning Reactor Drain Tank Room Hydrogen Concentration Page 2
Enclosures:
1.
2.
Notarized Affidavit Revised Section 9.3 from Letter No. 102-05116-CDM/TNW/RAB, Dated July 9, 2004, from C. D. Mauldin, APS, to U. S. Nuclear Regulatory Commission cc:
B. S. Mallett M. B. Fields G. G. Warnick A. V. Godwin NRC Region IV Regional Administrator NRC NRR Project Manager NRC Senior Resident Inspector Arizona Radiation Regulatory Agency (ARRA)
ENCLOSURE 1 NOTARIZED AFFIDAVIT STATE OF ARIZONA
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COUNTY OF MARICOPA 1, David Mauldin, represent that I am Vice President Nuclear Engineering and Support, Arizona Public Service Company (APS), that the foregoing document has been signed by me on behalf of APS with full authority to do so, and that to the best of my knowledge and belief, the statements made therein are true and correct.
David Mauldin Sworn To Before Me This /7JZ* Day Of nU!2z
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Notary Commission Stamp Revised Section 9.3 from Letter No. 102-05116-CDMITNW/RAB, Dated July 9, 2004, from C. D. Mauldin, APS, to U. S. Nuclear Regulatory Commission
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Revised Section 9.3:
Section 9.3 Loss-of-Coolant Accident Hydrogen Generation The post-LOCA hydrogen generation analysis was performed for Unit 1 and 3 PUR. The existing containment aluminum and zinc inventories remain unchanged by PUR. The PUR post-LOCA containment temperature profile is discussed in Section 6.2.2. A core wide oxidation rate of 1.0% was used to predict the quantity of hydrogen released because of the zirconium metal water reaction as a result of implementation of ZIRLOTM cladding refer to Section 6.1.
Consistent with the licensing basis, the hydrogen recombiners are assumed to be placed into service at 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br />. The analysis concluded that the peak bound hydrogen concentration remains less than 3.99% by volume.
As discussed in UFSAR Section 6.2.5 (Reference 9-5), and as accepted by the NRC as documented in the Standard Review Plan (SRP) (Reference 9-6), under postulated LOCA conditions, the Reactor Drain Tank (RDT) room may become an essentially closed room with the only venting occurring through an annular opening in the ceiling. The potential therefore exists for the accumulation of hydrogen in the RDT subcompartment to exceed the lower flammability concentration limit.
The maximum hydrogen concentration has been analyzed in the RDT room using the same NRC reviewed methodology as the original design (Reference 9-7). The analysis shows that the hydrogen concentration could be as high as 4.5 Volume % in the RDT room, well below the increased hydrogen concentration limit of 6 volume percent discussed in Regulatory Guide 1.7. Exceeding the hydrogen concentration lower flammability limit of 4 Volume % in the RDT room is acceptable because there is no ignition source in the room and the plume exiting the roof of the room mixes quickly with containment atmosphere, reducing the concentration to below the lower flammability limit. This clarification also applies to Unit 2. The results of the analyses and the conclusions remain the same for the three units at PVNGS.