ML20003E311
| ML20003E311 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 03/20/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20003E309 | List: |
| References | |
| NUDOCS 8104020859 | |
| Download: ML20003E311 (3) | |
Text
.
(D
[ps*t:.
s UNITED STATES
[ *,),.,,? j NUCLEAR REGULATORY COMMISSION
--yj.,y wassincrou. o. c. 2csss g?~~~ia)jl t
SAFETY EVALUATIOh BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDRENT NO. 41 TO FACILITY OPERATIhG LICENSE NO. CPR-66 DUQUESNE LIGHT COPPANY OHIO EDISCN COPPANY PEtiNSYLVAli!A ?OWER CCPPANY BEAVER VALLEY POWER STATION, UNIT li0. I t
DOCKET NO. 50-334 INTRODUCTION 9
By letter dated August 14, 1980, Duquesne Light Company (the licensee) proposed changes to the Technical Specifications for the Beaver Valley Power Station, Unit
.(
1.
The changes will~ increase the low-low steam generator water level reactor trip setpoint from 10% to 12% of the narrow range instrument ' scale. The revised value of 12% includes an allowance of 5% for channel accuracy, S% for post ac.cident environmental ' effects on the differential pressure transmitters, and 2%
' 'for reference leg-heatup compensation.
DISCUSSION
-High energy line breaks inside containment can result in heatup of the steam
. generatoc water level ins truments' reference leg.
Increased reference leg
. water.colum temperature will result in a decrease of the water colum density -
with.a ' consequent' apparent increase in the indicated steam generator water level
((1 e., indicated. level exceeding actual level). This potential level bias could
[DTN I
4 t
y
result in delayed protection signals (reactor trip and auxiliary feedwater initiation) that are based on low-low steam generator water level.
For the case of a feedline rupture, this adverse environment could be present and could delay the primary signal arising from declining steam generator water level (low-low 4
steam generator water level). High pressurizer pressure, over-temperature delta T, high containment pressure and safety injection are backup signals to steam generator water level with an adverse containrent environment.
For other high energy line breaks that could introduce a similar positive bias to the steam generator water level measurement, steam generator level does not provide the primary trip function 1
and the potential bias would not interfere with needed protective system actuation.
F EVALUATION Westinghouse (NSSS vendor for the Beaver Valley Plant) has advised that the potential temperature induced bias described above can be compensated for by raising the steam generator low-low water level setpoint.
Westinghouse has
- recommended a change in the allowable water level setpoint sofficient to accommodate the bias that could result from the highest containment temperatures possible prior to the occurrence of a containment high pressure trip.
The licensee has added three inches of insulation to the reference leg in order to minimize the effect of adverse containment temperatures on the reference leg.
The insulating material used is a foam glass which is wrapped with.010 inches tc type 304 stainless stecl-for protection.
Since the total error due to reference leg heatup cannot be completely-accounted for by insulating, the licensee has increased the low-low water it al setpoint two percent of the narrow range scale.
The licensee has stated that this new setpoint, recommended by Westinghouse,
a raintains the basis in the Technical Specifications, thus, accounting for the effects of reference leg heatup.
Based on our review of the licensee's submittal, we find the proposed changes to Table 2.2-1 of the Technical Specifications for the Beaver Valley Station, L* nit I acceptable.
Environmental Consideration We have determined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level and Having made will not result in any significant environmental impact.
we have further concluded that the amendment this determination involves an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFP. 551.5(d)(1), that an environnental impact statement or negative declaration and environ-mental impact appraisal need not be prepared in connection with the issuance cf this amendment.
~
' Conclusion We have concluded, based on the considerations discussed above, that:
(1) because the amendment does not involve a significant increase in the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the amendment does not involve a significant hazards consideration, (2) there is reascnable assurance that the health and safety of the public will not be endangered by operation in the prt;osed manner, and (3) such activitfes will be conducted in compliance with the Commission's regulations and the issuance of this anendment will nct be inimica'.
.to the cochon defense and security or to the nealth and safety of the public.
l Date: March 20,1981 P
l l
l
-