ML20151B940
| ML20151B940 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 04/05/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20151B938 | List: |
| References | |
| NUDOCS 8804120037 | |
| Download: ML20151B940 (3) | |
Text
.
[cuag'o UNITED STATES NUCLEAR REGULATORY COMMISSION o
{
I WASHINGTON, D. C. 2o666
\\, * * * * * /
.1 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION I
RELATED TO AMENDMENT NO.19 TO FACILITY OPERATING LICENM NO. NPF-47 GULF STATES UTILITIES COMPANY
, RIVER BEND STATION, UNIT 1
~
DOCKET NO. 50-458
1.0 INTRODUCTION
By letter dated June 18, 1987, the Gulf States Utilities Company, the licensee for the River Bend Station, Unit 1, proposed to change the plant Technical Specifications (TS) Table 3.3.2-2 for leak detection setpoints for the reactor water cleanup area temperatures (items 4.c.1 and 4.d.1),
and the RCIC/RHR steaa line high flow isolation (item 5.1).
The licensee provided additional clarification in a letter dated March 11, 1988.
The March 11, 1988 letter was in response to a request from the staff to document the clarification and did rot influence or change the basis for the proposed no significant hazards consideration issued on August 12, 1987.
The specific changes are as follows:
Reactor Water Cleanup (RWCU) Area Temperature - The licensee proposed to change the RWCU heat exchanger room ambient high temperature trip setpoint for RWCU isolation Item 4.c.1 from 5 98.5'F to 5 104.5'F and the allowable g
value from 5 101.5 F to 5 107.5 F.
The licensee also proposed to change the differential temperature trip setpoint in the above area, Item 4.d.1, from 5 33 F to 6 39 F and the allowable value from 5 36.5*F to 5 42.5'F.
The licensee stated that the proposed changes are required to avoid unnecessary engineered safety feature (ESF) isolation signals due to restricting RWCU heat-exchanger room ambient and differential temperature setpoints.
RCIC/RHR Steam Line High Flow Isolation - The licensee proposed to change the RCIC/RHR steam line high flow isolation initial trip setpoint Item 5.1, from 5 156" H O to 5 60.7" H O and the allowable value from 5 164.5" 2
2 H O to 5 64.2" H 0.
The licensee stated that the above change is necessary 2
2 as a result of the review of the RCIC/RHR steam line high flow setpoint.
2.0 EVALUATION i
Reactor Water Cleanup Area Temperature - The ifcensee stated that the original leak detection temperature setpoints were based on a predicted temperature in the containment area and assuming a steam leakage rate of i
25 gpm.
The proposed setpoints have the same analytical basis as the original setpoints with the exception that the initial temperature is based on actual temperature data rather than the predicted value.
The applied setpoint methodology, utilizing the actual temperature data, g18'clBN$il P
I
\\
' accounts for instrument inaccuracies and drift to ensure the margin of l
safety is maintained.
The licensee also stated that a review was performed to ensure that the existing design of the equipment and i
structures enveloped the higher normal operating temperature and thit the qualifisd life of the equipments were revised as necessary.
The Office for Analysis and Evaluation of Operational Data (AE00) issusd a report numbered AEOD/E705 on March 31, 1987, entitled "RWCU System Automatic Isolation and Safety Consideration." This report documents a review YT the Licensee Event Reports (LERs) from January 1984 through October 1986 concerning RWCU isolations and has made the following conclusions. Of all of the RWCU isolations; 74% were'due to spurious signals.
Slightly less than half of the isolations were initiateo by temperature signals.
Of the isolations where there was actual leakage from the RWCU pressure boundary, the usual initiating isolation signal was related to flow not to area temperatures.
Thus, a significant factor for RWCU pressure boundary leakage detectica is flow monitoring.
The-lice::see has not proposed any change in the ficw monitoring instrumentatior,.
RPIC/RHk Steam Line High Flow Actuation - The licensee stated that the Erig;nally specified initial setpoint of 5 156" H O for flow measuring i
2 instrumentation to isolate the RCIC/RHR steam line on high flow is below j
the break flow for an 8" RHR steam line break but may not have been low enough to isolate o'n a 4" RCIC steam line break. This is due to errors in the or ginal flow calculation which resulted in the overestimation of i
total steam flow.
The errors resulted from the eultiple operating modes of de DiiR system.
The proposed initial setpoint of 5 60.7" H O will 2
isolate down stream piping on both the 4" and 8" steam lia break and is Sased on steam flow to both loops of the RHR system in the steam condens-ing mode and to the RCIC taking suction fror the condensate storage t nk.
~
Since the setpoint is being lowered in the conservative direction th,e i
will be an increase rather than a decrease in the mergin of safety asso-i citted with this change. No change to the applicable note in the TS, Table 3.3.2-2 is proposed which states that the final setpoint is to be j
determined during testing prior to operation in the steam cor.densing mode i
following the NRC approval to operate in that mode.
3.0
SUMMARY
Bssed on the above, the staff concludes that the proposed change to the plant TS, Table 3.2.2-2 for leak detection setpoints for the RWCU heat exchanger r'. a ambielt high temperature, Item 4.c.1, and differential temperaturn
- em 4.cs.1 Tre acceptable since the margin of safety as defined '
W techr'c_
P ses is maintained and all the equipeent in the vironment to @ic5 it WJuld be exposed.
j area i <
it!" for e
at the proposed changes to plant TS, Table The s'.'. f
.N W.. detection initial setpnint for RCIC/RHR steam i
3.2.2s!,
c i
line hig? " c.
. s....
is acceptable since the proposed change is more conservat u t>..
'+
'ginal initial setpoint.
1 4
4 5
q_
^ -
4.0 ENVIRONMENTAL CONSIDERATION
The amendment involves a change in the installation or use of a facility coalponent located within the restricted area as def.ned in 10 CFR Part 20.
The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposures.
The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration cnd there has been no public comment on such finding.
Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR Section 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement er environ-mental assessment need be prepared in connection with the issuance of the amendment.
5.0 CONCLUSION
The staff has concluded, based on the considerations discussed aoove, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations, 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.
Date: April 5,1988 Principal Contributors:
R. Goel
.