ML042450147
| ML042450147 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 08/31/2004 |
| From: | Hartz L Dominion Nuclear Connecticut |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 03-373E, GL-03-001 | |
| Download: ML042450147 (7) | |
Text
Dominion Nuclear Connecticut, Inc.
hlilltront Power \\tation k q w k r r r b Ko.id W'.it~rtord. ( T 0(>185 August 31, 2004 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 k
Y borninion Serial No.
03-373E Docket No.
50-423 License No.
NPF-49 MPSLicNVDB R1 DOMINION NUCLEAR CONNECTICUT, INC. (DNC)
MILLSTONE POWER STATION UNIT 3 SUPPLEMENTAL INFORMATION, TRACER GAS INLEAKAGE TEST RESULTS, AND TECHNICAL SPECIFICATION CHANGES GENERIC LETTER 2003-01, CONTROL ROOM HABITABILITY On June 12, 2003, the NRC issued Generic Letter (GL) 2003-01, "Control Room Habitability," to all operating reactors. The GL requested information that demonstrates that the control room at each facility complies with the current licensing and design bases as well as applicable regulatory requirements. In a June 1, 2004 letter (Serial No. 03-373D), DNC provided the requested information for Millstone Power Station Units 2 and 3.
Based on the change in the tracer gas test schedule for MPS 3 documented in DNC letter (Serial No. 03-3738) dated March 5, 2004, DNC committed to provide supplemental information to complete the generic letter response by August 31, 2004.
DNC herein provides the Millstone Power Station Unit 3 (MPS 3) control room habitability envelope tracer gas inleakage test results. This information is contained in.
The DNC June 1, 2004 NRC Generic Letter 2003-01 response also committed to delineating a plan and schedule for any proposed technical specification changes for MPS 3 control room habitability envelope integrity upon completion of tracer gas inleakage testing. This information is contained in Attachment 2.
If you have any questions or require additional information, please contact Mr. Thomas Shaub at (804) 273-2763.
Very truly yours, Leslie N. Hartz Vice President - Nuclear Engineering Attachments
Serial No. 03-373E Generic Letter 2003-01 Response Page 2 of 2 Commitments made in this letter:
- 1. An amendment request for MPS 3 that will incorporate the intent of the current proposed TSTF-448 for a control room habitability program will be submitted within six months following either the approval of TSFT-448 or its adoption in the Consolidated Line Item Improvement Process (CLIIP) by the NRC, whichever is later.
cc:
U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406-1 41 5 Mr. V. Nerses Senior Project Manager US. Nuclear Regulatory Commission One White Flint North 11 555 Rockville Pike Mail Stop 8C2 Rockville, MD 20852-2738 Mr. S. M. Schneider NRC Senior Resident Inspector Millstone Power Station Serial No. 03-373E GENERIC LETTER 2003-01, CONTROL ROOM HABITABILITY SUPPLEMENTAL INFORMATION, TRACER GAS INLEAKAGE TEST RESULTS Millstone Power Station Unit 3 Dominion Nuclear Connecticut, Inc. (DNC)
Serial No. 03-373E Generic Letter 2003-01 Response Page 1 of 1 Operation Mode Tested Train A Emergency Filtration System Pressurization Train B Emergency Filtration System Pressurization Millstone Power Station Unit 3, Control Room Habitability Envelope Tracer Gas lnleakage Results Unfiltered lnleakage 20.1 k 3.6 scfm 7.1 k7.0 scfm With the assistance of NUCON International, Inc., control room habitability envelope tracer gas inleakage testing, in accordance with ASTM E741 test methodology, was completed and the results are summarized in Table 1.
Train B Isolation Dampers Closed, Neutral Pressure Table 1 Control Room Envelope Tracer Gas In leakage Test Results' (actual cubic feet per minute) 95 f 2 acfm Additional Information Current control room radiological analysis assumes a 10 cfm unfiltered inleakage (for ingresdegress activities) when the control room is at a positive pressure and a 115 cfm unfiltered inleakage when the control room is at a neutral pressure2.
The tracer gas inleakage test showed that the current radiological analysis inleakage assumption was met for the neutral pressure operating mode, but was not met for the positive pressure operating mode. An operability determination3 was performed that evaluated inleakage in excess of that which was assumed in the analysis.
The operability determination specified operational restrictions (e.g., maximum permitted containment leak rate and primary to secondary leak rate) affecting potential radiological release pathways to compensate for the higher measured positive pressure mode inleakage, which thereby maintains radiological consequences within the limits specified in the current licensing basis acceptance criteria of 5 rem whole body, 30 rem thyroid, and 30 rem skin dose limits. No credit was taken in the operability determination for the use of self-contained breathing apparatus or the use of potassium iodide.
NUCON International, Inc., Test Report "Control Room Habitability: Tracer Gas Leak Testing of the Millstone Unit 3 Control Room", Purchase Order No. 701 18900, July 27, 2004.
of Alternate Source Term", Table 2.6-1, May 27, 2004.
OD No. MP3-070-04.
1
. DCN Submittal Serial No.04-285, "MPS-3 Proposed Technical Specification Changes, Implementation 2
Serial No. 03-373E GENERIC LETTER 2003-01, CONTROL ROOM HABITABILITY SUPPLEMENTAL INFORMATION, TECHNICAL SPECIFICATION CHANGES Millstone Power Station Unit 3 Dominion Nuclear Connecticut, Inc. (DNC)
Millstone Power Station Unit 3, Plan and Schedule For Proposed Changes To The Technical Specifications For Control Room Habitability Envelope Integrity Parameter Unfiltered lnleakage During Periods of Neutral Pressure Unfiltered lnleakage During Periods of Positive Pressure
Background
Analysis Assumption 350 scfm 100 scfm NRC Generic Letter 2003-01 Item 1 (c) requests confirmation that existing technical specifications are adequate to verify CRE integrity and that CRE in-leakage is bounded by analysis assumptions. If current technical specifications have a AP surveillance requirement to demonstrate CRE integrity, the generic letter requests the basis for the conclusion that the current technical specifications remain adequate to be a demonstration of CRE integrity in light of the ASTM E741 testing results.
Assessment Bases This assessment of the need to change existing technical specification is based upon the alternate source term (AST) analysis inleakage assumptions that are shown in Table 2. The AST analysis was submitted for NRC review and approval on May 27, 2004.
Table 2 Control Room lnleakage Assumptions Employed in the AST Analyses4
Response
Based upon industry experience, plants with high inleakage values are typically those with HVAC equipment and ductwork located outside the control room habitability envelope boundary. Most all MPS 3 control room HVAC and ductwork is located within the habitability envelope.
Thus, MPS 3 has low susceptibility to this boundary degradation mechanism.
Because of the low leakage boundary design, recent tracer gas inleakage test results, and conservative inleakage assumptions contained in the proposed AST control room dose analysis, the existing technical specification for control room differential pressure (AP) surveillance (i.e., Technical Specification 4.7.7.e.2: Maintain a positive pressure of greater than or equal to 1/8 inch water gage at less than or equal to a pressurization flow of 230 cfm.) is considered sufficient to ensure that unfiltered inleakage is maintained within the inleakage values used in the proposed control room habitability DNC Correspondence to NRC, Serial No.04-285, MPS 3 -Proposed Technical Specification Changes, Implementation of Alternate Source Term", dated May 27, 2004 (Table 2.6-1) 4
analysis. Hence the current technical specifications remain adequate to demonstrate control room envelope integrity in light of the ASTM E741 testing results and the AST submittal.
Given that the Technical Specification 4.7.7.e.2 surveillance frequency is 24 months, a control room habitability program, consistent with the intent of TSTF-448, would provide additional assurance that the envelope inleakage remains within accident analysis assumptions. Therefore, an amendment request for MPS 3 that will incorporate the intent of the current proposed TSTF-448 for a control room habitability program will be submitted within six months following either the approval of TSFT-448 or its adoption in the Consolidated Line Item Improvement Process (CLIIP) by the NRC, whichever is later.