ML20244C399
| ML20244C399 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 03/28/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20244C398 | List: |
| References | |
| NUDOCS 8904200189 | |
| Download: ML20244C399 (3) | |
Text
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o UNITED STATES 8.
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NUCLEAR REGULATORY COMMISSION '
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I WASHINGTON, D. C. 20856
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAP. REACTOR REGULATION RELATED TO AMENDMENT NO. 6 TO FACILITY OPERATIt:0 LICENSE NO. NPF-76 HOUSTON LIGHTING & POWER COMPANY CITY PUBLIC SERVICE BOARD 0F. SAN ANTONIO CENTRAL POWER AND LIGHT COMPANY CITY OF AUSTIN, TEXAS DOCKE1 h0. 50-498
,S0llTH. TEXAS PWEC7: l'rIT 1
1.0 INTRODUCTION
Py application dated January 25, 1989, Houston Lighting & Power Ccrpery, et. cl., (the licensee) requestea three sets of changes to the Technical Specifications (Apperdix A to F c111ty Operating License f.'c. ?!PF-76) for South Tu ts Project, Unit 1.
The proposto cher.ges addressed in this Safety Evaluation wculd chu.se the value' of the fuel handlir.g tt;ilefrp exhaust tir subsystem electric heaters to reference operation at 38 kW instead of the current 50 kt'.
2.0 DISCUSSION The fuel hcndling building (FHB) exhaust uit liVAC system exhausts air frcr, the interior of the'FhB to the picnt main vent stack. This sutsytttr is desigr.(t es safety-related and seismic Cetegcry I and consists of two 100%
captity exhaust filter trains, thret EC% capacity exhaust booster fer.s, three 50% capacity main exhaust fans, ano associated dampers and instrurerta-tion. The systera design. exhaust air flow cupccity is 29,000 10% cubic feet per minute (CFM).
Each reduncant exhaust filter train cor,sists of three 33-1/3% capacity filter units. Each filter unit contains an electric heating elenent, profiiters, high efficiency particulate eir (HEPA) filters and carben absorber. The electric heating elements are provided to cecrease the reletive humioity of the incoming air. The efficiency of iodine removal by the charcoal absorbers is adversely affected by high relative hunitoity h,the air stream. The operability r,f the heater is determined pursuant to hhr.ical Specification 4.7.8.t.4 (Fuel l'analing Building Exhaust Air System) and 4.7.12.a.4 (Fuel Handlir,g Building Exhaust Air System -
Refueling Operations) which require verification that the heaters dissip6te 50 kW SkW when tested in accordance with ANSI N510-1980.
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A flow switch provided downstreen of each exhaust filter unit autoccticaliy
. turns off the heating element to prevert dcr..6ge to the element when the air flow rate drops below e minimum flow value. Currently the minimurii ficw setpoint is 9330 CFN. When all thrtc trLins are actuated the exhaust flow is split between the six operating filter units (two filter traitis, each cceposed of three filter units). Therefore, the flow through each unit is 4833 CFM (29,000 CFH oivided by 6), Since this flow rate is less than the setpoint, the flow switch prevents the heater f rom erlergizirig.
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When only one train is actu6ted, the flow through each of the three l.
operating filter units is 9667 CFM (29,000 CFM divioed by 3).
The offsite end control room dose calculations for the loss of coolant L
accident and fuel hand 11 rig accident are based on an iodine renovul efficiency i
. assucing that the relative humidity of the ir.cerring air is maintained et or below 70%. If the heaters are not actuated the relative huniidity cay not be below 7C1, ano the charcoal iodir.o rcrcvel efficiency may be decreesec' rcsLiting in high control room ano offsitc deses.
-Procedural changes hcyt teen implemented on Unit I which receire that i
operaters stut ccwn one filter train followir.g.. ESFAS ectuation after verifying that all cf the Fh5 exhaust systern components have actuated.
The licersto c6lculated that the doses reniain within 10 CFR Part 100, Standard Review Plcn (SRF) 15.7.4, and 10 CFR Part 50 Appendix f., General Desirr Criterion (GDC) 19 requirements with operster action within 30 minutes as directed in the ptocecures.
i The long tern sclutien to this problem is to derett the heaters from 50 kW j
to 38 kW.. At 38 kW the heste rr can operate at the lower f1cw rate (assun.ing alltrainsareoperating)withoutdamage. The incerning air to the charcoal filters will k n.zirtained at or below 70% relative hur..icity with various combinations of trains opercting; therefore, the existing c'est calculation asstr.ptices relative to iodine removal efficiencies will be nainteined.
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1 To reflect the fact that the design of the fuel handling building eybeust tir sitsystem heaters must be changed frun 50 kW to 38 kW, it is, therefore, rect LLLry that the Technical Specificerien: that contain the surveillar.cc requirements for those heators (4.).8.o.4 and 4.9.12.d.4) be n.cdified as proposed.
3.0 EVALUATION The staff has reviewed rrc' cercurs with the licensee's evelustion anc further f jrids, based on our review, that the rrcpcsec' chhnge is consistent I
with SRP 6.5.1, Rt.gulttery Guide 1.52, and GDC 61 as it relates to the I
design of systems for r6 bioactivity control undcr notti;al and postulated accident conditions, trd with the Standard Technical Specifications and is, therefore, acceptable, j
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s o 4'. 0 ENVIRONMENTAL CONSIDERATION The amendment relates to changes in installation or'use of'a facility component located within the restricted area.. The staff has determined
'that the amendment involves no significant increase'in the amounts and no i
significant change in the types of any effluents that may be released I
offsite and that there is no significant increase in individual.or cumula-i tive occupational radiation exposure. The Commission has previously 1
issued a proposed finding that the amendment involves no significant hazards
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consideration and there has been no public comment on such finding.
Accordingly, the amendment meets the eligibility criteria for categorical-exclusion set forth in 10 CFR 51.22(c)(9). ' Pursuant to 10 CFR 51.22(b),
no e.7vironmental impact statement or environmental assessment need be 1
prepared in connection with the issuance of this amendment.
5.0 CONCLUSION
i Based upon its evaluation of the proposed changes to the South Texas Project, Unit 1, Technical Specifications, the staff has concluded that:
there is reasonable assurance that the health and safety of the public will not be. endangered by operation in the proposed manner, and such activities will be conducted in compliance with the Commission's regula-tions and the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public. The staff, therefore, concludes tr,'at the proposed changes are acceptable, and are hereby incorporated into the South Texas Project, Unit 1 Technical Specifications. As a result of the time required to change the different trains of heaters to operate at 38 kW, the amendment will be fully implemented six weeks after date of issuance. The staff concurs and has no safety concerns with this approach.
Date: March 28, 1989 Principal Contributor:
C. Nichols i
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