ML20070M026
| ML20070M026 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 03/15/1991 |
| From: | Shelton D CENTERIOR ENERGY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| RTR-REGGD-01.097, RTR-REGGD-1.097 1879, NUDOCS 9103210014 | |
| Download: ML20070M026 (4) | |
Text
{{#Wiki_filter:. I CENTER 00R ENERGY Donald C. Shehon 300 Madison Avenue Vice President + Nuclear Toleoo, OH 436520001 Davb Besse (419)249 2300 Docket Number 50-346 License Number NPF-3 Serial Number 1879 March 15, 1991 United States Nuclear Regulatory Commission Document Control Desk Vashington, DC 20555 S
Subject:
Classification of Control Room Normal Ventilation Isolatitn Status for RG 1.97, Revision 3/ Resolution to Nuclear Regulatory (ommission Unresolved Item 346/80038-04 T Gentlemen: On June 28, 1984, Toledo Edison (TE) subra tted a letter (Serial Number 1059) describing the implementation of cemmitments to Regulatory Guide (RG) 1.97, Revision 3. The schedule for fulff111ng these commitments was based on compliance as defined by Davis-Besse acceptance criteria and guidelines provided in Serial Number 1059. Toledo Edison's methods for complying with RG 1.97 vere provided in that letter and two subsequent letters (Serial Numbert 1232 and 1236) submitted to resolve questions / clarifications submitted by the Nuclear Regulatory Commission-(NRC) in Log Number 1838, dated October 16, 1985. The NRC forwarded its final Safety 5' .1= tion Report (SER) X regarding Davis-Besse's conformance with RG 1.97 in an NRC letter (Log Number 2447) dated November 25, 1987. Toledo Edison committed to implement all actions for RG 1.97 Revision 3 conformance by the sixth refueling outage which began on January 26, 1990 and ended on July 5, 1990. Two inspections (Inspection Reports 50-346/88028 dated February 14, 1989, and 50-346/90021 dated November 21, 1990) were performed to verify TE's compliance to RG 1.97. The purpose.of this letter is to resolve Unresolved Item 346/88038-04 by providing the following: 1. Justification for dovngrading the Control Room Normal Ventilation System (CRNVS) Isolation Status from a ha 1.97 Category 1, Type A variable to a Category 2, Type D variable. '2. Verification of qualified isolation of safety-related cire"'*.y in the CRNVS. 9103210014 910315 PDR ADOCK 05000346 PDR g Opwohng Companies c l CISetand Elecmc muminatmg l h {j { } g Totedo Ed; son l
Docket Numbar 50-346 Lic:nsa Numbar NPF-3 Serial Number 1879 Page 2 NRC's UNRESOLVED ITEM 88038-04 "RG 1.97 required Environmental Qualification (EO) qualificetion from sensor to display for Category 1 variables. Honeyvell pressure switches PS 5301 and PS 5311 were part of the Category 1 Control Room Normal Ventilation Status (CRNVS) instrument loop and therefore vere required to be qualified. The licensee informed the inspectors that the switches were non-Class 1E. The inspectors determined that this position appeared to be contrary to the requirements of RG 1.97 in that the pressure svitches were part of the Class-1B instrument loop. Pending further NRC review, this is considered an Unresolved Item." FOLLOV-PP NRC INSPECTION REPORT 90021 "During the previous NRC RG 1.97 inspection, a review of the control room normal ventilation status (CRNVS) instrumentation revealed that, contrary to RG 1.97, Honeywell pressure switches PS 5301 and PS 5311 vere installed as non safety-related devices. During this inspection, the inspectors noted that the CRNVS instrument channel interfaced with a safety-related circuit where qualified isolation did not appear to be provided. The inspectors discussed the CRNVS pressure switch circuitry with the licensee and with LtR/SICB. The licensee had classified the CRNVS instrument loop as Category 1, Type A. RG 1.97, Revision 3, classifies CRNVS as Category 2. Type D. It appeared to the inspectors that this instrument loop meets the Category 2 criteria. The licensee committed to evaluated their designation of this variable as Category 1 Type A to determine if CRNVS can be downgraded and to document this review. The licensee also committed to review the circuit to determine if proper isolation of the circuit was provided." TOLEDO EDISON'S RESPONSE Toledo Edison has re-reviewed RG 1.97, Revision 3, the NRC inspection reports, and the Babcock and Vilcox (B&V) Owners roup RG 1.97 Task Force Evaluation of Selected RG 1 '7 Variaiiles (B&V Document #47-1150378-01). Based on this reviev, TE cc. curs that the CRNVS Isolation Status should properly be classified as a Category 2, Type D variable. RG 1.97, Revision 3, defines a Type D variable as "those variables that provide information to indicate the operation of individual safety systems and other systems important to safety." RG 1 ", Revision 3, further defines Category 2 variables as applying "to instrument tion designated for indicating system operating status." During emergency isolation of the control room, the normal control room isolation dac.pers are automatically closed to preclude the admission of airborne contaminants. The control room operator has manual controls for initiating the control Room Emergency Ventilation System (CREVS) to ensure satisfactory control room conditions following an accident. Emergency Procedures require that the operators verify CRNVS damper isolation via indication on the control room panel. Therefore, the Cr?VS damper position indication lights perform as a Category 2, Type D variable by providing information to indicate that the safety-related CRNVS isolation dampers vere demanded closed.
. - ~. -.. ~. - - -Dockst Nu2bar 50-346 Liesnsa Nu2bar NPF-3. Serial Number 1879 Page 3~ l Toledo Edison has re-reviewed Davis-Besse dravings (7749-E-60B, SH-14A, Revision '6, and 7749-E-60B, SH-140, Revision 2), the USAR (Sections 8.1.5 and 7.1.2.3) and IEEE Standard 384, 1977 to verify that proper isolation is provided between the 1E and non-1E portions of the CRNVS instrument channel. Relays R5X and R9X provido acceptable isolation per-Section 6.2.2.2 of IEEE Standard 384, 1977. The standard lists coil to contact relays as acceptable isolation devices for instrumentation and control circuits. i Only f. hose components in the CRNVS that are required to isolate the normal venti:iation to the control room during accident conditions are safety-related. Either a SFAS level 1 actuation or a high station vent radiation detection vill deenergize solenoid valves SV 5301 and SV 5311. The instrument air vill then bleed off to close the CRNVS isolation dampers. Control room habitability vill then_be maintained by using the CREVS. The solenoid valves and the CRNVS isolation dampers are designed to fall in the fail-safe position (close). Upon depressurization of instrument air, the Honeywell pressure switches, PS_5301 and PS 5311, actuate to provide indication in the control room. The tunction_of the pressure switches is not to isolate the ventilation flow path to the control-t room. Rather, the svitebes provide indication in the control room that the l CRNVS dampers were directed to close. -Therefore, since proper isolation exists, .S 5301 and PS 5311 are not required toYif fety-related. p i" The'informaticn-provided in this letter reso ves Unresolved Item 346/88038-04 by-concurring with the NRC in downgrading the CRNVS to a Category 2,- Type D variable and'by verifying that proper isolation exists in the CRNVS circuitry. Accordingly, Attachment 1 serves as an addendum to TE's June 28, 1984 submittal. Should-you have any questions concerning this matter, please contact Mr. R. V. Schrauder,'Hanager - Nuclear-Licensing, at (419) 249-2366. Very tr y yours, ff\\ % Attachment cci P. H. Byron, DB-1 NRC Senior Resident Inspector A. B. Davis, Regional Administrator, NRC Region III E J. Randall Hall,_NRC Senior Project Manager H. J. Kopp, NRC Region III Inspector l-H. D. Lynch, NRC Senior ~ Project Hanger Utility Radiological-Safety Board 1 ~
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