ML081200136
| ML081200136 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 04/28/2008 |
| From: | Gerald Bichof Dominion Nuclear Connecticut |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 07-0440A, NLOS/MAE R2 | |
| Download: ML081200136 (7) | |
Text
Dominion Nuclear Connecticut, Inc.
,000 Dominion Boulevard, Glen Allen, Virginia 2,060
\X'd, Address: www.dom.com April 28, 2008 U. S. Nuclear Regulatory Commission Serial No. 07-0440A Attention: Document Control Desk NLOS/MAE R2 One White Flint North Docket Nos. 50-336/423 11555 Rockville Pike License Nos. DPR-65 Rockville, MD 20852-2738 NPF-49 DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNITS 2 AND 3 SIGNIFICANT HAZARDS CONSIDERATION CONTROL ROOM HABITABILITY* RECENTLY IRRADIATED FUEL On July 13, 2007, Dominion Nuclear Connecticut, Inc. (DNC) submitted a request for an amendment to the Technical Specifications (TSs) for Millstone Power Station Units 2 and 3 (MPS2 and MPS3) (Serial No. 07-0440). The proposed amendment would revise TS requirements related to control room envelope habitability consistent with the intent of NRC-approved Technical Specification Task Force (TSTF) Standard Technical Specification Change Traveler, TSTF-448, "Control Room Habitability," Revision 3. In response to a November 21,2007 NRC Request for Additional Information (RAI), DNC submitted information related to the application of the term "recently irradiated fuel" (Serial No. 07-0790, dated December 7, 2007). The NRC forwarded an additional RAI on January 28, 2008. DNC responded to this RAI on March 5, 2008 (Serial No 08-0050) and March 25, 2008 (Serial No.
08-0050A).
As discussed in a March 5, 2008 teleconference between Mr. John D. Hughey (NRC) and Mr.
William D. Bartron (DNC), ONC is submitting a revised no significant hazards consideration determination (NSHCD) as an attachment to this letter. This revised NSHCD includes a consideration of the issues associated with recently irradiated fuel and supersedes the NSHCD which was referenced in DNC's July 13, 2007 submittal in its entirety.
Should you have any further questions in regard to this submittal, please contact Ms. Margaret A. Earle at (804) 273-2768.
Gerald Bischof Vice President - Nuc ear Engineering COMMONWEALTH OF VIRGINIA COUNTY OF HENRICO The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Gerald T. Bischof, who is Vice President - Nuclear Engineering of Dominion Nuclear Connecticut, Inc. He has affirmed before me that he is dUly authorized to execute and file the foregoing document in behalf of that company, and that the statements in the document are true to the best of his knowledge and belief.
Acknowledged before me this <:iB~day of ~I' L. ,2008.
My Commission Expires: Au.~,,~r SI, JQtJg .
MARGARET B. BENNETT Notary PubI1c3S4-3~
~~ Notary Public Commonwealth of Vlrglnra My Commlilion Expire. Aug 31. 2008
Serial No. 07-0440A Docket Nos. 50-336 50-423 Response to CR Habitability RAI Page 2 of 2 Attachment Commitments made in this letter: None cc: U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406-1415 Mr. J. D. Hughey Project Manager U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 08 B3 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station Director Bureau of Air Management Monitoring and Radiation Division CT Department of Environmental Protection 79 Elm St.
Hartford, CT 06106-5127
Serial No. 07-0440A ATTACHMENT CONTROL ROOM HABITABILITY TECHNICAL SPECIFICATION IMPROVEMENT SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION MILLSTONE POWER STATION UNITS 2 AND 3 DOMINION NUCLEAR CONNECTICUT, INC.
Serial No. 07-0440A Docket Nos. 50-336 50-423 Resp. to CR Habitability RAJ Attachment, Page 1 of 4 CONTROL ROOM HABITABILITY TECHNICAL SPECIFICATION IMPROVEMENT CONSIDERATION OF RECENTLY IRRADIATED FUEL SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION Description of Amendment Request:
There are two changes in this amendment request.
a) The first change is proposed to the plant specific technical specifications (T8),
to strengthen T8 requirements regarding control room envelope (CRE) habitability by changing the action and surveillance requirements associated with the limiting condition for operation operability requirements for the CRE emergency ventilation system, and by adding a new T8 administrative controls program on CRE habitability.
b) The second change involves removing the T8 requirement for the CRE emergency ventilation system to be operable while handling irradiated fuel after sufficient radioactive decay has occurred to ensure control room doses remain below the limit specified in 10 CFR 50.67. The purpose is to establish a time where operability of the CRE emergency ventilation, which is typically used to mitigate the consequences of a fuel handling accident (FHA), is no longer needed to meet the current license basis CRE dose limit of 5 rem Total Effective Dose Equivalent (TEDE). This decay time defines recently irradiated fuel. The new information for recently irradiated fuel provides a mechanism for applying a cutoff in fission product decay to various T8, including the CRE emergency ventilation system, where the concept applies.
T8 applicability statements are revised with "recently irradiated" replacing "irradiated" with additional information included in the Bases for the T8. The decay period (300 hours0.00347 days <br />0.0833 hours <br />4.960317e-4 weeks <br />1.1415e-4 months <br /> for MP82 and MP83; 350 hours0.00405 days <br />0.0972 hours <br />5.787037e-4 weeks <br />1.33175e-4 months <br /> for MP83 after Stretch Power Uprate (SPU>> has been shown by analysis to provide sufficient decay such that, assuming a design basis FHA, CRE radiological consequences are within the acceptance criteria of 10 CFR 50.67.
Accompanying the proposed T8 change are appropriate conforming technical changes to the T8 Bases. The proposed revisions to the Bases also include editorial and administrative changes to reflect applicable changes which were made to improve clarity, conform with the latest information and references, and correct factual errors.
The proposed revision to the TS and associated Bases is consistent with 8T8 as revised by T8TF-448, Revision 3.
Serial No. 07-0440A Docket Nos. 50-336 50-423 Resp. to CR Habitability RAI Attachment, Page 2 of 4 Basis for proposed significant hazards consideration determination:
As required by 10 CFR 50.91 (a), an analysis of the issue of significant hazards consideration is presented below:
Criterion 1 - The Proposed Change Does Not Involve a Significant Increase in the Probability or Consequences of an Accident Previously Evaluated a) The proposed change does not adversely affect accident initiators or precursors nor alter the design assumptions, conditions, or configuration of the facility. The proposed change does not alter or prevent the ability of structures, systems, and components (SSCs) to perform their intended function to mitigate the consequences of an initiating event within the assumed acceptance limits. The proposed change revises the TS for the CRE emergency ventilation system, which is a mitigation system designed to minimize unfiltered air leakage into the CRE and to filter the CRE atmosphere to protect the CRE occupants in the event of accidents previously analyzed.
An important part of the CRE emergency ventilation system is the CRE boundary. The CRE emergency ventilation system is not an initiator or precursor to any accident previously evaluated. Therefore, the probability of any accident previously evaluated is not increased. Performing tests to verify the operability of the CRE boundary and implementing a program to assess and maintain CRE habitability ensure that the CRE emergency ventilation system is capable of adequately mitigating radiological consequences to CRE occupants during accident conditions, and that the CRE emergency ventilation system will perform as assumed in the consequence analyses of design basis accidents. Thus, the consequences of any accident previously evaluated are not increased. Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
b) The proposed change revising the TS from "irradiated fuel movement" to "movement of recently irradiated fuel assemblies," referred to hereafter as the "recently irradiated fuel" change, is used to establish operational conditions on CRE emergency ventilation where significant radioactive releases can be postulated. These operational conditions are consistent with the design basis analysis. Inoperability of the CRE emergency ventilation system cannot increase the probability of a fuel handling accident (FHA) because the CRE emergency ventilation system is not considered an initiator to a FHA. The definition will allow fuel movement without the requirement of an operable CRE emergency ventilation system as long as fuel exceeds the decay time specified in the TS bases. As submitted to the NRC in the Response to Request for Additional Information, dated December 7, 2007, this decay time
Serial No. 07-0440A Docket Nos. 50-336 50-423 Resp. to CR Habitability RAI Attachment, Page 3 of 4 is 300 hours0.00347 days <br />0.0833 hours <br />4.960317e-4 weeks <br />1.1415e-4 months <br /> for MPS2 and MPS3 (350 hours0.00405 days <br />0.0972 hours <br />5.787037e-4 weeks <br />1.33175e-4 months <br /> for MPS3 SPU). The consequences of a FHA while moving non-recently irradiated fuel without an operable CRE emergency ventilation system remain less than the limits specified in 10 CFR 50.67. Other TS changes relating to "recently irradiated fuel" do not involve any accidents previously evaluated. Therefore the proposed "recently irradiated fuel" change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
Criterion 2 - The Proposed Change Does Not Create the Possibility of a New or Different Kind of Accident from any Accident Previously Evaluated a) The proposed change does not impact the accident analysis. The proposed change does not alter the required mitigation capability of the CRE emergency ventilation system, or its functioning during accident conditions as assumed in the licensing basis analyses of design basis accident radiological consequences to CRE occupants. No new or different accidents result from performing the new surveillance or following the new program. The proposed change does not involve a physical alteration of the plant (i.e., no new or different type of equipment will be installed) or a significant change in the methods governing normal plant operation. The proposed change does not alter any safety analysis assumptions and is consistent with current plant operating practice. Therefore, this change does not create the possibility of a new or different kind of accident from any accident previously evaluated.
b) The proposed "recently irradiated fuel" change does not affect nor create a different type of FHA. The FHA analyses continue to assume that all the iodine and noble gases that become airborne, escape and reach the CRE with no credit taken for deposition, filtration, or containment of the release.
The proposed "recently irradiated fuel" change does not involve the addition or modification of equipment or the design of plant systems. The proposed "recently irradiated fuel" change does not alter the mitigating capability of the CRE emergency ventilation system after a FHA involving recently irradiated fuel. This change only permits the CRE emergency ventilation system to be inoperable for a FHA involving fuel that has decayed beyond the "recently irradiated fuel" definition in the TS Bases. For this consideration, the dose consequences to CR occupants remain below the limits required in 10 CFR 50.67. No new or different accidents result from defining the time after shutdown that CRE emergency ventilation system is required to be operable.
Other TS changes relating to "recently irradiated fuel" do not create any accidents. Therefore, the proposed "recently irradiated fuel" change regarding recently irradiated fuel does not create the possibility of a new or different kind of accident from any previously analyzed.
Serial No. 07-0440A Docket Nos. 50-336 50-423 Resp. to CR Habitability RAI Attachment, Page 4 of 4 Criterion 3 - The Proposed Change Does Not Involve a Significant Reduction in the Margin of Safety a) The proposed change does not alter the manner in which safety limits, limiting safety system settings or limiting conditions for operation are determined. The proposed change does not affect safety analysis acceptance criteria. The proposed change will not result in plant operation in a configuration outside the design basis for an unacceptable period of time without compensatory measures. The proposed change does not adversely affect systems that respond to safely shut down the plant and to maintain the plant in a safe shutdown condition. Therefore, the proposed change does not involve a significant reduction in a margin of safety.
b) The proposed "recently irradiated fuel" change decay time limits on recently irradiated fuel are used to establish operational conditions on the CRE emergency ventilation system where specific activities represent situations where significant radioactive releases can be postulated. Safety margins and analytical conservatisms have been evaluated through the use of accepted methodology. Although CRE doses have slightly increased for all but the MPS3 AST, there was not a significant reduction in the margin of safety.
These operational conditions are consistent with the design basis analysis and are established such that the radiological consequences to the CRE occupants are below the limits specified in 10 CFR 50.67. Other TS changes relating to "recently irradiated fuel" are not related to a margin of safety.
Therefore, operations of the facility in accordance with the proposed "recently irradiated fuel" changes would not involve a significant reduction in the margin of safety.
Based upon the above assessment and the previous discussion of the amendment request, DNC concludes that the proposed change does not involve a significant hazards consideration.