ML030030119
| ML030030119 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  (DPR-077, DPR-079) |
| Issue date: | 12/31/2002 |
| From: | Salas P Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| TAC MB2972, TAC MB2973 | |
| Download: ML030030119 (7) | |
Text
December 31, 2002 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:
In the Matter of
)
Docket Nos. 50-327 Tennessee Valley Authority
)
50-328 SEQUOYAH NUCLEAR PLANT - CONTROL ROOM HABITABILITY ANALYSIS FOR DESIGN BASIS ACCIDENTS - TRITIUM PRODUCTION (TAC NOS.
MB2972 AND MB2973)
Reference:
TVA letter to NRC dated August 30, 2002, Sequoyah Nuclear Plant (SQN) - Units 1 and 2 -
Technical Specification (TS) Change No. 00-06, Response to Request for Additional Information (RAI) (TAC Nos. MB2972 and MB2973)
The Tennessee Valley Authority (TVA) committed in the referenced letter to conduct control room habitability analyses for the Updated Final Safety Analysis accident scenarios and provide the results including a tabulation of the analysis inputs and assumptions used. The enclosure to this letter provides the results of TVAs analysis.
No new commitments are contained in this letter. This letter is being sent in accordance with NRC Regulatory Issue Summary
U.S. Nuclear Regulatory Commission Page 2 December 31, 2002 2001-05. Please direct questions concerning this issue to me at (423) 843-7170 or J. D. Smith at (423) 843-6672.
Sincerely, Original signed by Pedro Salas Licensing and Industry Affairs Manager I declare under penalty of perjury that the foregoing is true and correct. Executed on this 31 day of December 2002.
Enclosure cc (Enclosure):
Mr. Lawrence E. Nanney, Director Division of Radiological Health Third Floor L&C Annex 401 Church Street Nashville, Tennessee 37243-1532 Mr. Frank Masseth Framatome ANP, Inc.
3315 Old Forest Road P. O. Box 10935 Lynchburg, Virginia 24506-0935
E-1 ENCLOSURE TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT (SQN)
UNITS 1 AND 2 RADIOLOGICAL CONSEQUENCES OF ACCIDENTS FOR THE SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 ADDRESSING IMPLEMENTATION OF TRITIUM PRODUCING BURNABLE ABSORBER RODS (TPBARS)
E-2 Control room dose calculations have been performed for the steam generator tube rupture and fuel-handling accident design basis analyses. These analyses supplement the loss-of-coolant and main steam line break control room dose analyses previously discussed in the response to Question 2 in TVAs letter to NRC Dated August 30, 2002, Sequoyah Nuclear Plant (SQN) - Units 1 and 2 -
Technical Specification (TS) Change No. 00-06, Response to Request for Additional Information (RAI) (TAC Nos. MB2972 and MB2973). Control room dose calculations were not specifically performed for the loss of AC power, waste gas decay tank rupture, and ejected rod transients given the similarity of the transients to the steam line break, fuel-handling, and loss-of-coolant accidents respectively. Based on quantification of the potential radioactive releases and identification of the release points (and associated atmospheric dispersion factors), the steam line break analysis will bound the loss of AC power transient, the fuel-handling accident will bound the waste gas decay tank rupture, and the loss-of-coolant accident will bound the ejected rod transient.
Consistent with the loss-of-coolant accident and main steam line break control room dose calculations discussed in the response to Question 2 in the TVA letter to NRC dated August 30, 2002, calculations for the steam generator tube rupture and fuel-handling accidents were performed to establish the thyroid, whole-body and beta skin doses resulting from the releases of iodines and noble gases (beta skin doses also included the doses from the release of tritium). Since tritium in the gaseous form is not a significant dose contributor (i.e., a minor beta radiation emitter with no retention in the body), it was conservatively assumed that all tritium is released in the form of water as tritium oxide and is absorbed into the body as a dose contributor. No tritium contribution was included in the thyroid dose calculations since the thyroid dose is defined as the dose resulting from radioactive iodine releases. In accordance with NRC General Design Criteria (GDC) No. 19, the control room dose analysis acceptance criteria was established as 30 roentgen equivalent man (rem) thyroid, 5 rem whole-body, and 30 rem beta skin.
To account for the radiological consequences of tritium in the tritium production core, a Total Effective Dose Equivalent (TEDE) was also calculated. As discussed in the response to Question 3 in the TVA letter to NRC dated August 30, 2002, the TEDE values were calculated for information purposes and do not replace the current SQN design basis whole body and thyroid dose acceptance criteria.
E-3 The analysis inputs and assumptions for the SQN control room dose calculations are summarized in Table 1. The atmospheric dispersion factors listed in Table 1 are based on the conservative application of the results of the calculation provided as Attachment 2 to the TVA letter to NRC dated August 30, 2002.
The results of the control room doses analyses are summarized in Table 2. The calculations establish the limiting event for control room dose as the fuel-handling accident inside containment. All calculated radiological consequences meet the acceptance criteria of GDC 19.
E-4 TABLE 1 ANALYSIS INPUTS AND ASSUMPTIONS USED IN CONTROL ROOM DOSE ANALYSES Steam Generator Tube Rupture Control Room Volume 2.6E5 cubic feet Air Inflow (normal operation) 3200 cfm Filtered Intake Flow (emergency) 1000 cfm Filtered Recirculation Flow (emergency) 2600 cfm Filter Efficiency for Iodine 95 percent Unfiltered Inleakage 51 cfm Atmospheric Dispersion Factor 0-2 hours 1.93E-3 sec/m3 2-8 hours 7.02E-4 sec/m3 Occupancy Factor 0-24 hours 1.0 24-96 hours 0.6 96-720 hours 0.4 Breathing Rate 3.47E-4 m3/sec Shielding 0.5 inches of steel Fuel-Handling Accident Control Room Volume 2.6E5 cubic feet Air Inflow (normal operation) 3200 cfm Filtered Intake Flow (emergency) 1000 cfm Filtered Recirculation Flow (emergency) 2600 cfm Emergency Mode Time Delay 5 minutes Filter Efficiency for Iodine 95 percent Unfiltered Inleakage 51 cfm Containment Isolation 28 seconds Atmospheric Dispersion Factor FHA Inside Containment 5.63E-4 sec/m3 FHA Outside Containment 1.80E-3 sec/m3 Occupancy Factor 0-24 hours 1.0 24-96 hours 0.6 96-720 hours 0.4 Breathing Rate 3.47E-4 m3/sec Shielding 0.5 inches of steel
E-5 TABLE 2 SEQUOYAH CONTROL ROOM DOSE CALCULATION RESULTS Steam Generator Tube Rupture Pre-Existing Accident Acceptance Iodine Spike Initiated Limit Iodine Spike Thyroid Dose 15.2 rem 2.9 rem 30 rem Whole Body Dose 0.8 rem 0.9 rem 5 rem TEDE 1.1 rem 1.0 rem Beta-Skin 2.0 rem 1.9 rem 30 rem Fuel-Handling Accident Outside Inside Acceptance Containment Containment Limit Thyroid Dose 1.6 rem 27.8 rem 30 rem Whole Body Dose 1.0 rem 0.1 rem 5 rem TEDE 4.7 rem 1.6 rem Beta-Skin 4.5 rem 0.9 rem 30 rem