ML11187A360
| ML11187A360 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 06/27/2011 |
| From: | - No Known Affiliation |
| To: | Division of Operating Reactor Licensing |
| References | |
| Download: ML11187A360 (6) | |
Text
1 WBN2Public Resource From:
Boyd, Desiree L [dlboyd@tva.gov]
Sent:
Monday, June 27, 2011 9:17 AM To:
Epperson, Dan; Poole, Justin; Raghavan, Rags; Milano, Patrick; Campbell, Stephen Cc:
Crouch, William D; Hamill, Carol L; Boyd, Desiree L
Subject:
TVA letter to NRC_06-27-11_RAI Response Regarding April 27, 2011 NRC Audit Attachments:
06-27-11_RAI Response Regarding April 27, 2011 NRC Audit_Final.pdf PleaseseeattachedTVAletterthatwassenttotheNRCtoday.
- ThankYou,
~*~*~*~*~*~*~*~*~*~*~*~
Désireé L. Boyd WBN2LicensingSupport SunTechnicalServices dlboyd@tva.gov 4233658764
Hearing Identifier:
Watts_Bar_2_Operating_LA_Public Email Number:
442 Mail Envelope Properties (7AB41F650F76BD44B5BCAB7C0CCABFAF20489624)
Subject:
TVA letter to NRC_06-27-11_RAI Response Regarding April 27, 2011 NRC Audit Sent Date:
6/27/2011 9:17:25 AM Received Date:
6/27/2011 9:17:31 AM From:
Boyd, Desiree L Created By:
dlboyd@tva.gov Recipients:
"Crouch, William D" <wdcrouch@tva.gov>
Tracking Status: None "Hamill, Carol L" <clhamill@tva.gov>
Tracking Status: None "Boyd, Desiree L" <dlboyd@tva.gov>
Tracking Status: None "Epperson, Dan" <Dan.Epperson@nrc.gov>
Tracking Status: None "Poole, Justin" <Justin.Poole@nrc.gov>
Tracking Status: None "Raghavan, Rags" <Rags.Raghavan@nrc.gov>
Tracking Status: None "Milano, Patrick" <Patrick.Milano@nrc.gov>
Tracking Status: None "Campbell, Stephen" <Stephen.Campbell@nrc.gov>
Tracking Status: None Post Office:
TVANUCXVS2.main.tva.gov Files Size Date & Time MESSAGE 312 6/27/2011 9:17:31 AM 06-27-11_RAI Response Regarding April 27, 2011 NRC Audit_Final.pdf 223630 Options Priority:
Standard Return Notification:
No Reply Requested:
No Sensitivity:
Normal Expiration Date:
Recipients Received:
U.S. Nuclear Regulatory Commission Page 2 June 27, 2011
Enclosure:
- 1. Supplemental Information for the Watts Bar Unit 2 (WBT) Hot Zero Power (HZP) Steam Line Break (SLB) Analysis for RAI Response cc (Enclosure):
U.S. Nuclear Regulatory Commission Region II Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, Georgia 30303-1257 NRC Resident Inspector Unit 2 Watts Bar Nuclear Plant 1260 Nuclear Plant Road Spring City, Tennessee 37381
U.S. Nuclear Regulatory Commission Page 3 June 27, 2011 bcc (Enclosure):
Stephen Campbell U.S. Nuclear Regulatory Commission MS 08H4A One White Flint North 11555 Rockville Pike Rockville, Maryland 20852-2738 Charles Casto, Deputy Regional Administrator for Construction U.S. Nuclear Regulatory Commission Region II Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, Georgia 30303-1257
Enclosure Watts Bar Nuclear Plant (WBN) Unit 2 - Response to Request for Additional Information (RAI) Regarding April 27, 2011 NRC Audit Supplemental Information for the Watts Bar Unit 2 (WBT) Hot Zero Power (HZP) Steam Line Break (SLB) Analysis for RAI Response
Reference:
Westinghouse Letter WBT-D-3109 NRC Question A.4:
Address the staffs question, raised during the audit, regarding fuel rod mechanical design rod internal pressure (i.e., clad liftoff) concerns during the steamline break event down to the accumulator injection set pressure.
TVA Response:
The fuel design limit for rod internal pressure is that:
- 1. The internal pressure of the lead rod in the reactor will be limited to a value below that which could cause (1) the diametral gap to increase due to outward cladding creep during steady-state operations and (2) extensive DNB propagation to occur,
- 2. DNB propagation is limited for Condition II events, and
- 3. The increased fuel pressure does not introduce a significant number of additional DNB events in the safety analysis of Condition III and IV events.
Cycle-specific evaluations are performed using NRC-approved models and methodologies in order to confirm that all of the above criteria are met. These evaluations include analyzing the effects of steamline break events down to the accumulator injection set pressure.
NRC Question A.5:
What, if any, actions would plant operators initiate if the moderator temperature coefficient (MTC) surveillance measurement was within the most-negative allowable MTC, but beyond the cycle specific moderator density coefficients used in the steamline break analysis?
TVA Response:
There are no separate, tiered actions for Technical Specification requirements and cycle-specific values. The required actions are defined by Technical Specifications Limiting Condition for Operation (LCO) 3.1.4. Related information is provided in Reference 5 (WCAP-15088, Rev. 1) of the Core Operating Limits Report (COLR) section of the Watts Bar Unit 2 Technical Specifications (Section 5.9.5).