View source for RBG-26069, Forwards Supplemental Info to Attachment 1 to 870318 Submittal Re Automatic Depressurization Sys Actuation,Per NRC Request

{{Adams
| number = ML20215C371
| issue date = 06/09/1987
| title = Forwards Supplemental Info to Attachment 1 to 870318 Submittal Re Automatic Depressurization Sys Actuation,Per NRC Request
| author name = Booker J
| author affiliation = GULF STATES UTILITIES CO.
| addressee name = 
| addressee affiliation = NRC OFFICE OF ADMINISTRATION &amp; RESOURCES MANAGEMENT (ARM)
| docket = 05000458
| license number = 
| contact person = 
| document report number = RBG-26069, TAC-61528, TAC-65128, NUDOCS 8706180089
| document type = CORRESPONDENCE-LETTERS, INCOMING CORRESPONDENCE, UTILITY TO NRC
| page count = 2
| project = TAC:61528, TAC:65128
| stage = Supplement
}}

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oJ GULF STATES ' UTILITIES COMPANY RIVER BEND STATION '   POSr OFFICE BOX 220    St. FRANCISVILLE. LOUISlANA 70775
                                                    . AREA CODE 604     636 6094       346-0651 June 9, 1987
                                                                                                      ~ RBG- 26069 File Nos. G9.5, G9.25.1.4 U.S. Nuclear Regulatory Commission Document Control Desk-Washington, D.C. 20555 Gentlemen:
River Bend Station - Unit 1 Docket No. 50-458-Gulf. States Utilities Company provides. the ' attached? supplemental information to its March 18, 1987, Attachment 1, submittal as - requested in discussion with -the Staff.                         If additional.information is required, please contact Mr. Rick King at;(504) 381-4146~                             .
s                                           Sincerely, s
[qJ.E. Booker Manager-River Bend Ochesight.
River Bend Nuclear (i.;up JCD/ ERG / 3 je Attachment cc:    U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76011 Senior Resident Inspector U.S. Nuclear Regulatory Commission.
P.O. Box 1051 St. Francisville, LA 70775
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8706180089 870609                                                                                                   s
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1   PDR      ADOCK 05000458 P                       PDR
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                                  .                                                                        Attachment 1 e
Supplemental Information on ADS Actuation March 18, 1987 Submittal The Technical Specifications being revised require Surveillance Testing of the Automatic Depressurization System (ADS) Actuation Instrumentation including functional tests of manual initiation circuits and the logic systems.                       Monthly functional tests on ADS actuation instrumentation demonstrate opernbility of all portions of the control system except for the manual initiation switches and the solenoids. The Safety Relief Valves (SRVs) are not required to lift during the testing. However, SRV testing and actuations at River Bend Station (RBS) provide justification for this Technical Specification change because successful operation of the SRV solenoids was performed. The subject testing requires operation of the SRV solenoids which cannot be accomplished during power operation without affecting plant status. Thus, the only portion of the system which has not been operated since the last successful completion of the surveillance test is the manual switch.
These manual switches provide back-up to the automatic initiation logic for ADS. This system is required to automatically actuate during a design basis accident in which the High Pressure Core Spray (HPCS) is required, but fails. ADS reduces pressure in the vessel to allow low                                            l pressure Emergency Core Cooling Systems (ECCS) to inject into the                                               l vessel. Manual initiation would be required in the event that HPCS and                                          l' automatic ADS actuation did not occur. The probability of an accident is not increased by this Technical Specification change because the effected equipment is not postulated to initiate an accident. The consequences of an accident would only be effected in the event that ADS was required and failed to actuate. The probability of failure is low based on 1) the design of the system is single failure proof with two independent initiation systems, 2) monthly functional tests which show operability of the system except for manual initiation and                                               SRV solenoids,                       3)   SRV actuations during startup testing which show operability of the SRV solenoids, and 4) no reported failures were identified for manual initiation switches as shown by a review of Nuclear Plant Reliability Data System (NPRDS) reports.
The 18 month functional                                      tests being revised by       this     Technical Specification change have been successfully completed one time during startup testing. While portions of the system have been retested following work on the system the 18 month functional tests have not been re-run following any modifications or repair work.
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