ML20079G424
| ML20079G424 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 09/26/1991 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20079G412 | List: |
| References | |
| NUDOCS 9110090103 | |
| Download: ML20079G424 (6) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N05. 28 AND 19 TO FACILITY OPERATING LICENSE N05. NPF-76 AND NFF-80 HOUSTON LIGHTING & POWER COMPANY CITY PUBLIC SERVICE BOARD OF SAN ANTONIO CENTRAL POWER AND LIGHT COMPANY CITY OF AUSTIN, TEXAS DOCKET NOS. 50-498 AND 50-499 l
SOUTH TEXAS PROJECT, UNITS 1 AND 2
1.0 INTRODUCTION
l By letter dated July 14, 1989 (ST-HL-AE-2940), Houston Lighting & Power Company, al,, (the licensee) requested changes to the Final Safety Analysis Report et.
l (FSAR) for ; w South Texas Project, Units 1 and 2.
The changes to the FSAR would revise Sections 6.4, 6.5, Appendix 7A, 9.4,15,6, and 15.7 by replacing i
I previously calculated offsite and control room radiological doses with the results of reanalyses.
The request for these revisions resulted mainly from l
the licensee's single failure analysis of the electric heater (previously unconsidered) in the fuel handling building and control room HVAC systems.
With the submittal of the Updated Final Safety Analysis Report (UFSAR), the proposed changes then became applicable to that document.
The current design basis accider.is in
'e South Texas UFSAR affected by the licensee's hcater failure analysis anc.ose recalculations include the LCCA, the fuel handling accident and the gaseous waste processing system failure l
accident.
The dose calculations for the control room operator are also affected.
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2.0 BACKGROUND
The engineered safety feature filter systems for South Texas Project, Units l
1 and 2 include:
(1) the fuel handling building (FHB) exhaust subsystem, and l
(2) the main control room HVAC makeup and cleanup filter system.
The FHB exhaust subsystem consists of two redundant filter traias, and each train corsists of three filter units to tritigate the radiological consequences ot the fuel handling accident as well as the LOCA.
The main control room HVAC l
makeup and cleanup filter system consists of three redundant filter units to l
9110090103 910926 PDR ADOCK 00000490 p
maintain the habitability of the control room against radiological consequences during and following a postulated design basis accident.
Each filter unit for the FHB exhaust subsystem and main control room cleanup filter system consists of, among other things, an electrical heater to reduce the moisture in the air stream to less than 70 percent relative humidity in order to protect the charcoal adsorber from moisture.
3.0 DISCUSSION in the South Texas UFSAR, the licensee evaluated all components in the filter units against single active failure criterion except the heater.
Ir. this proposed UFSAR revision, the licensee addressed the effect of previously unconsidered filter heater failures in the FHB and control room HVAC systems by recalculating of fsite and control room operator doses following a LOCA, a fuel-handling accident, and a gaseous waste processing system (GWPS) failure.
The licensee postulated the occurrence of an air flow imbalance and low-flow in a filter unit, which would trip the heater in the filter trai., causing the reduction of charcoal adsorber iodine removai efficiency.
TFe licensee further Dostulated that it would take 30 minutes for the operators to detect and correct flow imbalar.cc and activate a standby filter unit.
The staff accepted the licensee's postulations and used charcoal adsorber iodine removal efficiencies of 30 percent for organic and 90 percent for elemental iodines during the first 30 minutes at greater than 70 percent relative humidity following an accident.
In reviewing the licensee's analyses, the staff independently calculated the thyroid and whole-body doses for the LOCA, the fuel handling accident, and WGPS failure.
The staff's assumptior; used in calculating the doses to the control room operator and offsite doses are the same as those shown in the South Texas safety evaluation report (SER) Tables 6.1, 15.5, and 15.6 except the charcoal adsorber iodine removal efficiencies for the first 30 minutes following an accident.
The staff's calculated control room opetator doses are summarized in Table 1.
For dose calculations, tne staff used revised iodine prottetion factors given in Table 2.
The offsite doses are shown in a revision to Table 15.1 of the South Texas SER.
On t basis of this evaluation, the staff concludes that the electric heater failure in the filter unit will still leave the control room in a safe and habitable condition during and following a design basis accident by providing adequate protection against radiation so that the radiological exposures to the control room operator will be within the limits specified in General Design Criteria 19 of Appendix A to 10 CFR Part 50 and within the gJidelines provided in Standard Review Plan Section 6.4, and that the offsite thyroid and whole-body doses are still within the referenced values specified in 10 CFR Part 100.
Therefore, the staff finds the South Texas UFSAR changes as proposed by the licensec to be acceptable.
The basis for staff acceptance is that thc proposed UFSAR changes will not alter our ccnclusions in the South Texas SER (NUREG-0781) dated April 1986, l
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4.0 STATE CONSULTATION
In accordance with the Concission's regulations, the Texas State official was notifled of the proposed issuance of the amendment.
The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendments change a requirement with respect to installation or use of l
a facility component located within the restricted area as defined in 10 CFR Part 20.
The NRC st?f f has determined that the amendments involve no significant increase in the amaunts, and no significant chang 9 in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendments involve l
no significant hazards consideration, and there has been no public comment on such finding (54 FR 42857).
Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the iss 'nce of the araendment.
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- 6. 0 CONCLUSION The Commission has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
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Principal Contributor:
Jay Y. Lee Date:
September 26, 1991 Attachments:
1.
Table 1 - Control Room Operator Doses 2.
Table 2 - Iodine Protection factors 3.'
Revision to Table 15.1 of the l
TABLE 1 CONTROL ROOM OPERATOR DOSES (rem)
Calculated Origina11 Revised SRP 6.4 Thyroid dose-91 16,6 30 Whole-body dose 3,1 3,1 5
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25ection 6.4 of South Texas SER dated April 1986.
TABLE 2 IODINE PROTECTION FACTORS (IPF)
'I Elemental and Par,ticulate lodines IPF l
(1) Heater Failure 0-30 min 575 30 min - 30 day 1050 (2) Filter Bypass 0-30 day 870 Organic Iodine
'(1) Heater Failure 0-30 min 145 30 min - 30 day 1050 (2) Filter Bypass 0-30 day 870
Table 1E.1 Radiological consequences of design-basis accidents, in rems
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Exclusion area boundary Low population zone Postulated accident Thyroid Whole Body Thyroid Whole body Loss-of-coolant eccident Containment leakage 0-2 hours 150 3.6 20.5 0.49 2-8 hours 22.6 0.50 8-24 hours 12.0 0.21 l
24-96 hours 8.9 0.Cb 96-720 hours 6.4 0.02 l
Total containment leakage 141 3,6 69.1 1.27 ECCS component leakage 1.0
<0.1 1,8
< 0.1 Supplementary purge 11.5
<01 1.6
<0.1 subsystem contribution i
Iodine re-evolution during 11.8
<0.1 1.6
<0.1 spray recirculation
_i contribution Total 174.3 3.6 75.4
- 1. 3 Steamline break outside containment Fuel failures caused by stuck 88 0.4 47 0.3 control rod case Accident-induced spike case 3.0
< 0.1 2.5
<0.1 Control rod ejection Containment leakage pathway 30
<1.0 36
<1.0 Secondary system release 6
<1.0 0, 7
< 0.1 pathway Fuel handling accident In fuel building case 26 0.7 4.1 0.1 Inside containment case 29 0.2 3.9 0.04 Small line break outside containment Letdown line failure 1.3
<0.1 0.2
<0.1 Pressurizer sample line 2.1
< 0.1 0.3
<0.1 failure Steam generator tube rupture
- Case 1 (coolant activity del-131 at 60 pCl/gr)
Case 2 (coolant activity del-131 at 1 pC1/gm)
- Confirmatory itees.
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