ML052340484
| ML052340484 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 08/05/2005 |
| From: | Pace P Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BL-03-001, TAC MB9872 | |
| Download: ML052340484 (5) | |
Text
I-I.
Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381-2000 AUG 0 5 25 10 CFR 50.54(f)
U. S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C. 20555-0001 Gentlemen:
In the Matter of
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Docket No. 50-390 Tennessee Valley Authority WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 -
BULLETIN 2003-01 POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY SUMP RECIRCULATION AT PRESSURIZED WATER REACTORS -
REQUEST FOR ADDITIONAL INFORMATION (RAI) (TAC NO. MB 9872)
The purpose of this letter is to respond to NRC's request for additional information concerning the subject bulletin responses dated August 8, 2003, April 6, 2004, and November 19, 2004.
This RAI was received by electronic mail (e-mail) on June 3, 2005 from the NRC WBN Project Manager.
TVA's responses were discussed in a teleconference call with NRC reviewer on June 10, 2005.
In a July 11, 2005 e-mail, NRC requested TVA to supplement the Bulletin response as discussed in the teleconference call with NRC.
The Enclosure provides the response to NRC's concerns.
There are no regulatory commitments associated with this submittal.
If you have any questions concerning this matter, please call me at (423) 365-1824.
/0lo Pmled
, reCYd PaW
U.S. Nuclear Regulatory Commission Page 2 AUG 0 5 2005 I declare under penalty of perjury that the foregoing is true and correct.
Executed on this 5th day of August, 2005.
Sincerely, P
. Pace Manager, Site Licensing and Industry Affairs Enclosure cc (Enclosure)
NRC Resident Inspector Watts Bar Nuclear Plant 1260 Nuclear Plant Road Spring City, Tennessee 37381 Mr. D. V. Pickett, Project Manager U.S. Nuclear Regulatory Commission MS 08G9 One White Flint North 11555 Rockville Pike Rockville, Maryland 20852-2738 U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth St., SW, Suite 23T85 Atlanta, Georgia 30303
ENCLOSURE WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION BULLETIN 2003-01 The following provides TVA's responses to NRC's questions as understood from the June 10, 2005 teleconference call concerning TVA's response to the subject bulletin dated November 19, 2004.
In a July 11, 2005 electronic mail NRC requested TVA to supplement the Bulletin response as discussed in the teleconference call with NRC.
NRC QUESTION 1 Does any procedural direction exist to refill the refueling water storage tank (RWST) after a plant went on recirculation, assuming no blocked sump?
TVA RESPONSE Once the plant transitions to recirculation, it remains there for 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />.
During this period, as during any extended loop activity, the operators review the lit annunciators and take the actions as specified in the Annunciator Response Procedures that can be taken in the existing plant condition.
This would include Annunciator Response Instruction, ARI-124-130, for Annunciator 127-D, RWST LEVEL START MAKEUP.
The actions for this annunciator direct the operators to initiate makeup to RWST.
This is the procedural direction that would start RWST makeup without a blocked sump.
NRC QUESTION 2 Action 6 of page E-l1 implies that more water would never be injected from the RWST to the sump.
TVA RESPONSE At the end of the paragraph under Action 6, add:
"However, the Technical Support Center guidance contains instructions to evaluate the need for RWST refill and allows water to be pumped from the refilled RWST by the emergency core cooling system (ECCS) pumps, with consideration of instrument flooding and containment integrity precautions associated with excessive containment flood level."
Procedural guidance is in place to initiate refill of the RWST with or without a blocked sump; however, current conditions would be considered prior to injecting additional water in containment.
The Technical Support Center's E-1
ENCLOSURE WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION BULLETIN 2003-01 evaluation would consider the containment water level at the time and the instrumentation relied upon above flood levels.
To ensure containment integrity, containment pressure with the additional water would also be a consideration prior to injection.
NRC QUESTION 3 Supplement the response to the second question to verify that, following RWST injection and initiation of recirculation, control room operators have procedures in place to provide water to the reactor vessel from alternative sources of water outside of the RWST (i.e., RWST bypass lines).
TVA RESPONSE Procedures for use of makeup sources of water once the preferred sources have been depleted are currently being developed.
TVA had previously initiated a Problem Evaluation Report (PER) which identified that procedures were not in place for utilizing other water sources (i.e.,
high pressure fire protection water) as stated in the design system description for flood mode boration makeup system.
These procedure revisions are being tracked by the PER.
E-2
U.S. Nuclear Regulatory Commission Page 2 A-G Q 5 2005 Enclosure cc (Enclosure)
A. S. Bhatnagar, LP 6A-C M. F. DeRoche, ADM lQ-WBN J. C. Fornicola, LP 6A-C J. M. Frisco, EQB 2A-WBN J. E. Hinman, ADM 1B-WBN G. J. Laughlin, MOB 2R-WBN G. W. Morris, BR 4X-C NSRB Support, LP 5M-C K. W. Singer, LP 6A-C J. E. Semelsberger, EQB 2W-WBN E. J. Vigluicci, ET 1OA-K K. W. Whittenburg, SP2B-C Sequoyah Licensing Files, OPS 4C-SQN EDMS, WT 3B-K M:\\SUBMIT\\BL 2003-01 RAI Response.doc