ML11105A214

OL - Revised Component Cooling System RAI 9.2-CSS-6

ML11105A214
Person / Time
Site:	Watts Bar
Issue date:	03/17/2011
From:	Office of Nuclear Reactor Regulation
To:	Division of Operating Reactor Licensing
References
Download: ML11105A214 (4)

Text

1 WBN2Public Resource From:

Poole, Justin Sent:

Thursday, March 17, 2011 9:12 AM To:

garent@tva.gov; Crouch, William D Cc:

fakoontz@tva.gov; Elton, Thomas L; WBN2HearingFile Resource; Lyon, Fred; Milano, Patrick

Subject:

Revised Component Cooling System RAI 9.2-CSS-6 Attachments:

Revised RAI 9 2-CSS-6.docx On March 11, 2011, the NRC sent a request for additional information (RAI) regarding the component cooling system via email. In preparing the formal letter, the staff made revisions to the questions. See the attached document as to ensure that the RAI questions are understandable, the regulatory basis is clear, there is no proprietary information contained in the RAI, and to determine if the information was previously docketed.

JustinC.Poole ProjectManager NRR/DORL/LPWB U.S.NuclearRegulatoryCommission (301)4152048 email:Justin.Poole@nrc.gov

Hearing Identifier:

Watts_Bar_2_Operating_LA_Public Email Number:

335 Mail Envelope Properties (19D990B45D535548840D1118C451C74D7F50843DE6)

Subject:

Revised Component Cooling System RAI 9.2-CSS-6 Sent Date:

3/17/2011 9:12:03 AM Received Date:

3/17/2011 9:12:05 AM From:

Poole, Justin Created By:

Justin.Poole@nrc.gov Recipients:

"fakoontz@tva.gov" <fakoontz@tva.gov>

Tracking Status: None "Elton, Thomas L" <tlelton@tva.gov>

Tracking Status: None "WBN2HearingFile Resource" <WBN2HearingFile.Resource@nrc.gov>

Tracking Status: None "Lyon, Fred" <Fred.Lyon@nrc.gov>

Tracking Status: None "Milano, Patrick" <Patrick.Milano@nrc.gov>

Tracking Status: None "garent@tva.gov" <garent@tva.gov>

Tracking Status: None "Crouch, William D" <wdcrouch@tva.gov>

Tracking Status: None Post Office:

HQCLSTR02.nrc.gov Files Size Date & Time MESSAGE 593 3/17/2011 9:12:05 AM Revised RAI 9 2-CSS-6.docx 21903 Options Priority:

Standard Return Notification:

No Reply Requested:

No Sensitivity:

Normal Expiration Date:

Recipients Received:

REQUEST FOR ADDITIONAL INFORMATION REGARDING FSAR SECTION 9.2.2, COMPONENT COOLING SYSTEM (CCS)

TENNESSEE VALLEY AUTHORITY WATTS BAR NUCLEAR PLANT, UNIT 2 DOCKET NO. 50-391 By letter to the U.S. Nuclear Regulatory Commission (NRC) dated March 4, 2009 (ADAMS Accession No. ML090700378), the Tennessee Valley Authority (TVA) submitted an update to its application for a facility operating license for Watts Bar Nuclear Plant (WBN), Unit 2. The NRC staffs review of the information provided by TVA, as supplemented by amendments to the WBN Unit 2 Final Safety Analysis Report (FSAR), and TVAs responses to the staffs requests for additional information, is in progress. The NRC staff requests the following additional information to complete its review of the proposed application.

Request for Additional Information (RAI)

=

Background===

In TVA letter dated December 10, 2010, the applicant provided the following:

a) Enclosure 3, Summary Heat Load and Flow Tables for RAI 9.2-CCS-4. This table shows CCS heat loads and flows for:

(1) LOOP (loss of offsite power) with loss of Train B (2) LOOP with loss of Train A (1A & 2A).

It is apparent that loss of Train A is the worst case single failure with only CCS HX C available for Train B.

b) Response to RAI 9.2-CCS-1 that The project has performed calculations which demonstrate that there is sufficient Essential Raw Water Cooling (ERCW) and Component Cooling System capability to bring the non-accident unit to Cold Shutdown within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from entry into hot standby mode.

Questions:

A) For (a) (1) above with LOCA (Unit 1) and Cold Shutdown (Unit 2), it appears that the CCS is capable of removing 56,220 kBTU/hr in CCS Train 1A and 93,230 kBTU/hr in CCS Train 2A.

1) With this capability of CCS for a LOOP and loss of Train B, explain the capability of the shared CCS for Watts Bar 1 & 2 to comply with GDC 5. [in that systems important to safety shall not be shared among nuclear power units unless it can be shown that such sharing will not significantly impair their ability to perform their safety functions, including, in the event of an accident in one unit, an orderly shutdown and cool down of the remaining unit]

2) What is the time to reach cold shutdown of the non accident unit? List major assumptions.

2 B) For (a) (2) above with LOCA (Unit 1) and Cold Shutdown (Unit 2), it appears that the CCS is capable of removing 55,162 kBTU/hr in CCS Train 1B and 73,567 kBTU/hr in CCS Train 2B.

1) With this capability of CCS for a LOOP and loss of Train A, explain the capability of the shared CCS for Watts Bar 1 & 2 to comply with GDC 5 as described in (A) (1) above.

2) What is the time to reach cold shutdown of the non accident unit? List major assumptions.

C) How do the calculations mentioned in b) above relate to Enclosure 3, Summary Heat Load and Flow Tables for RAI 9.2-CCS-4.

D) Revise the FSAR as necessary to describe the design basis for adherence to GDC 5.