ML20154D168
| ML20154D168 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 09/09/1988 |
| From: | Cockfield D PORTLAND GENERAL ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20154D156 | List: |
| References | |
| NUDOCS 8809150173 | |
| Download: ML20154D168 (6) | |
Text
l PORTLAND GENERAL ELECTRIC COMPANY l'
EUGENE WATER & ELECTRIC BOARD AND PACIFIC POWER & LICHT COMPANY TROJAN NUCLEAR PLANT Operating Licenso NPF-1 Docket 50-344 License Chango Application 171 This Licenso Chango Application requests modifications to Operating i
Lic9nso NPF-1 for the Trojan Nuclear Plant to reviso the prossurizer low-pressure safety injection sotpoint in the Trojan Technical Specifications.
PORTLAND CENERAL ELECTRIC COMPANY l
By
\\(
U D.W.Cocif[d Vice President Nuclear Subscribed and sworn to before me this 9th day of September 1988.
k 4
/
OMyCommission Notary Public of Ofogon 4c e d
/
/
0 8809150173 090909 PDR ADOCK 05000344 P
PNV l
trojen Nucisar Plant LCA 171 Docket 50-344 Attachment A License NPF-1 Page 1 of 5 Summary License Change Application (LCA) 171 is required to provido a revised Technical Specification sotpoint for the pressurizer low-pressure safety injection. This change is necessary to accommodate new instrumentation that will be used to monitor narrow-range pressurizer pressure.
Reason for Change Since September 1987, the Trojan Nuclear Plant has experienced twelve failures of the transmitter used to monitor narrow-range pressurizer pressure.
Extensivo investigations have been completed and it has been determined that the appropriato action is to change to a diffe. ant transmitter design.
Since the now transmitters have a greater accident-induced inaccuracy than the existing transmitters, a reovaluation of the applicable set-points was necessary. This reevaluation resulted in an increased pressurizer low-pressure safety injection sotpoint. The high-t ressurizer pressure, low-prossurizor pressure, and overtemperaturo AT reactor trip setpoints remained unchanged since they are not required to be actuated in the harsh environment created by an accident.
Description of Change The new sotpoint and allowablo value has been calculated for the pressurizer low-pressure safety injection.
The change is based on the new transmitter's accident-induced inaccuracy. The new pressurizer low-pressure safety injection sotpoint will be 1807 psig, with an associated allowgblo valuo of 1799 psig.
The remaining safety functions that utilize the pressurizor pressure signal woro ovaluated, and their setpoints woro determined to be satis-factory. Those are safety functions that are not required to actuate in tho harsh environment created by an accident.
Differences in the normal operatina channel statistical allowance were minor and did not affect the sotpoints.
Dotalled_Safoty Evaluation This proposed LCA modifies the Trojan Technical Specifications regarding a new notpoint for the proscurizor low-pressuro safety injection.
1ho proposed chango is to Section 3.0, Table 3.3-4 of the Technical Specifications.
Trojan Nuclear Plant LCA 171 Dockot 50-344 Attachment A Licenso NPF-1 Page 2 of 5 In accordance with Titio 10 Code of Fodoral Regulations 50.59 (10 CFR 50.59), LCA 171 is judged to involvo no unreviewod safety question based on the following:
1.
The sotpoint proposed by the LCA doos no'. ?ncreasa the probability of occurrence or the consequences of an accadent or malfunction of equipment important to safety previously evaluated in tho safety analysis report.
The purpose of the pressurizer low-pressure safety injection sotpoint is to trip the reactor and actuato the engineered safety fontures during a loss-of-coolant accident (LOCA). The new notpoint for the replacement transmitters accommodatos an increase in the accident-induced environmental errors.
Trojan's accident analysos assumo an actuation at 1700 psig for the pressurizer low-prossure safety injection. The now Technical Specification limit ensures that this assumod value will not be exceeded. The new limit takes into consideration instrument uncertainty, circuit loop uncertainty, and the harsh environment induced uncertainty. This new setpoint still providos the margin necessary to ensure Plant protection consistent with the FSAR analyses.
To ensure that the sotpoint assumed in the safety analyses are not exceeded, a Channel Statistical Allowanco (CSA) is datormined for the actual sotpoint.
The major contributor to the CSA is the environ-mental allowanco.
The environmental allowanco for the replacement transmitters is greater than for the transmitters currently installed, and is reflected in the proposed sotpoint.
In conclusion, the now sotpoint value has boon increased to account for the increased environmental allowanco, and providos assurance of engineored safety features actuation prior to excooding the limits established in the safety analysos.
The original safety analysis was bounding for the previous sotpoint and is still bounding for the now setpoint. Thus, thoro is no increaso in probability or consequences of a previously evaluated accident.
2.
This proposed LCA doos not create the possibility of an accident or malfunction of a different typo than any evaluated previously in the safety analysis report.
The only chango to the Plant or its operation is in the proposed setpoint. The transmitter changeout will not involvo any changes to the Plant protection syr. tom or associated circuitry.
The original transmitters will be replaced with functionally equivalent components with comparablo susceptibility to environmental conditions. The adjustment of the sotpoint to a more rostrictivo limit to incorporate the increased environmental allowanco does not create the possibility of a now or different kind of malfunction or accident.
Trojan Nuclear Plant LCA 171 Docket 50-344 Attachment A Licenso NPF-1 Pago 3 of 5 3.
This proposed LCA does not result in a reduction in any margin of safety as defined in the basis for any Technical Specification.
The now setpoint will not change the margin of safety since the effect of the increased environmental allowance will be accounted for in the process signals.
The original safety analysis is still bounding; therefore, this proposed LCA does not involvo a reduction in a margin of safety.
No physical changes in the Plant design or operation are proposed.
The new sotpoint providos consistent Plant protection by accounting for the increased environmental allowanco in the process signals.
For those reasons, it is PGE's determination that the proposed change does not involve an unroviewed safety question.
Environmental Evaluation The proposed chango does not affect Plant dischargos to the environment and consequently does not present an unroviewed environmental question.
Significant Hazards Determination This proposed LCA modifies the Trojan Technical Specification regarding a new sotpoint for the pressurizer low-pressure safety injection protectivo function. The proposed changes are to Section 3.0, Tablo 3.3-4 of the Technical Specifications.
Sinco September 1987, the Trojan Nuclear Plant has experienced eleven f ailures of the transmitter used to monitor narrow-rango pressurizer pressure.
Extensivo investigations havo been completed and it has been determined that the appropriato action is to change to a different transmitter design.
Sinco the now transmitters have a greater accident-induced inaccuracy than tho existing transmitters, a roovaluation of the applicable sot-points was necessary. This roevaluation resulted in an increased pressurizer low-pressuro safety injection sotpoint. The high-prossurizor pressuro, low-prossurizor pressure, and overtemperaturo AT roactor trip setpoints romalnod unchanged sinco they are not required to be actuated in the harsh environment created by an accident.
In accordance with Title 10 of the Codo of Federal Regulations.
Section 50.92 (10 CFR 50.92), LCA 171 is judged to involvo no significant hazards based on the following:
1.
The proposed notpoint chango does not significantly increaso the probability or consequences of an accident previously evaluated.
I
=
Trojan Nuclear Plant LCA 171 Docket 50-344 Attachment A License NPF-1 Page 4 of 5 The purposo of the pressurizer low-pressure safety injection sotpoint is to trip the reactor and actuate the engineered safety features during a loss-of-coolant accident (LOCA). The new setpoints for the replacement tecnsmitters accommodato an increaso in the accident-induced environmental errors. Howevor, the now sotpoint conforms to the original and still-bounding safoty analyses.
Trojan's accident analysos assumo an actuation at 1700 psig for the pressurizor low-pressure safety injection.
The new Technical Speci-fication limit ensures this assumed valuo will not be exceeded. The new limit takes into consideration instrument uncertainty, circuit loop uncertainty, and the harsh environment-induced uncertainty.
This new sotpoint still provides the margin necessary to ensure Plant protection consistent with the FSAR analyses.
To ensure that the sotpointo assumed in the safety analysis are not exceeded, a Channel Statistical Analysis (CSA) is determined for the actual setpoint. The major contributor to the CSA is the environ-mental allowanco. The environmental allowance for the replacement transmitters is greater than that for the transmitters currently installed, and is reflected in the proposed setpoint.
In conclusion, the new setpoint value %as been increased to account for the increased environmental allowans', and providos assurance of engincored safety features actuation priot to exceeding the limits established in the safety analyses.
The or. sinal safety analysis was bounding for the previous sotpoint, and is t ill bounding for the new sotpoint. Thus, there is no increaso in protebility or consequences of a previously ovaluated accident.
2.
This LCA does not create the possibility of a new or different kind of accident from any accident previously evaluated.
The only change to the Plant or its operation is in the proposed sotpoint.
The transmittor changeout will not involve any changes to the Piant protection system or associated circuitry.
The pressure transmitters currently in uso will bo replaced with functionally equivalent components with comparablo susceptibility to adverso environmental conditier.s. The adjustment of the sotpoint to a more restrictivo limit te incorporate tho increased environmental allow-anco does not create the possibility of a now or different kind of accident.
3.
This LCA does not involvo a significant reduction in a margin of safety.
The now notpoint will not chango tho margin of safety since the effect of the increased environmental allowance will be accounted for in the process signals.
The original safety analyses are still bounding; thereforo, this proposed LCA does not involvo a significant reduction in a margin of safoty.
e Trojan Nuclear Plant LCA 171 Docket 50-344 Attachment A License NPF-1 Pago 5 of 5 Guidance concerning the appilcation of tho three standards of 10.CFR 50.92 addressed above is provided in the March 6, 1986 Federal Register (51 FR 1750-51), which lists examples that may/may not involve significant hazarde considerations.
Examplo 2 of amendments that are considered not likely to involvo significant hazards considorations applies to the changes proposed heroin and states:
"A chango that constitutes an additional limitation, restriction or control not presently included in the Technical Specifications, e.g.,
a mors stringent wurveillance requirement.."
No physical changos in the Plant design or operation are proposod. The new sotpoint provides consistent Plant protection by accounting for the increased environmental allowance in the process signals.
For theso reasons, it is PGE's determination that the proposed change does not involvo a significant hazards consideration.
Reference PCE Calculation TE-146, "Pressurizer Pressure Trip Sotpoints -
Rosemount 1154H", dated September 1988.