ML20237L394
| ML20237L394 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 08/21/1987 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| NUDOCS 8708280085 | |
| Download: ML20237L394 (2) | |
Text
o TENNESSEE VALLEY AUTHORITY CHATTANOOG A. TENNESSEE 374o1 SN 157B Lookout place
/tVG 211987 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 SEQUOTAH NUCLEAR PLANT (SQN) UNITS 1 AND 2 - NRC INSPECTION REPORT 50-327, -328/87-30; REEVALUATION OF RESPONSE TO VIOLATION 50-327/82-25-01 i
1 In response to Gary G. Zech's letter to S. A. White dated July 20, 1987, TVA has reevaluated the potential radiological consequences resulting from Emergency Gas Treatment System (EGTS) inoperability as reported in Reportable Occurrence Report SQRO-50-327/82107, dated September 24, 1982, and subsequently cited in violation 50-327/82-25-01, The reevaluation was primarily based on the decrease in time for Reactor Coolant System (RCS) source term de."y by conservatively establishing that time as the time from mode 3 entry to the time that EGTS became inoperable (i.e., the elevation 690 annulus door and the containment access area outer door were concurrently opened) versus the original assumption of RCS source term decay time from mode 3 entry to the time that the EGTS was discovered inoperable (i.e., the doors were found to be open).
It should be noted that the reevaluation also assumed a later time for mode 3 entry (derived from the unit operator's daily journal) as 0450 hours0.00521 days <br />0.125 hours <br />7.440476e-4 weeks <br />1.71225e-4 months <br /> versus the originally assumed 0345 hours0.00399 days <br />0.0958 hours <br />5.704365e-4 weeks <br />1.312725e-4 months <br />.
Therefore, the revised RCS source term decay tima was assumed as a 16.67-hour period (i.e., from 0450 hours0.00521 days <br />0.125 hours <br />7.440476e-4 weeks <br />1.71225e-4 months <br /> [ mode 3 entry) to 2130 hours0.0247 days <br />0.592 hours <br />0.00352 weeks <br />8.10465e-4 months <br /> [the time the EGTS was made inoperable by personnel entry into the containment annulus]).
This reevaluation, utilizing more realistic assumptions, has yielded a result that shows the original calculation was conservative with regard to iodine release; thereby, the reevaluation resultant inhalation dose is less than that previously reported, i.e., 200 rems at the site boundary vercus the previous analysis result of 240 rems.
From the reevaluation results, it can still be concluded that the potential radiological consequences for a postulated loss of coolant accident would have been within 10 CFR 100 limits.
If you have any questions, please telephone M. R. Harding at 615/870-6422.
Very truly yours, TENNESSEE VALLEY AUTHORITY 8708280005 B7082.
PDR ADOCK 05000327 O
PDR 1
gR. Oridley, Director i
Nuclear Safety and Licensing fj \\
O cc:
See page 2 k0 An Equal Opportunity Employer
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U.S. Wuclear Regulatory Commission AdJB 211987 cc:
Mr. C. G. Zech, Assistant Director for Inspection Programs Office of Special Projects U.S. Nuclear Regulatory Commission 101 Marietta Street, NW, Suite 2000 Atlanta, Georgia 30323 Mr. J. A. Zwolinski, Assistant Director for Projects Division of TVA Projects Office of Special Projects U.S. Nuclear Regulatory Commission 4350 East West Highway EWW 322 Bethesda, Maryland 20814 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37T/9