ML20247D408
| ML20247D408 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 09/01/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20247D405 | List: |
| References | |
| NUDOCS 8909140244 | |
| Download: ML20247D408 (3) | |
Text
_ - _ _ _ _ - _ _ _ _ _
q UNITED STATES
.f g
NUCLEAR REGULATORY COMMISSION O '.
[
W S SHINGTON, D. C. 205$5
\\..+ /
q j
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION j
RELATED TO AMENDMENT NO. b TO FACILITY OPERATING LICENSE NO. NPF-43 DETROIT EDIS0N COMPANY WOLVERINE POWER SUPPLY COOPERATIVE, INCORPORATED FERMI-2 DOCKET NO. 50-341
1.0 INTRODUCTION
any (DECO or the licensee)
By letter dated May 10, 1989, the Detroit Edison Comp (TS) appended to Facility requested amandment to the Technical Specifications Operating License No. NPF-43 for Fermi-2. The proposed amendment would revise the TS to reflect design changes for the Reactor Protection Systen (RPS) to be completed during the upcoming refueling outage scheduled to start September 1989. The design change will eliminate the Backup Manual Scram function and add further redundancy to the RPS capability to manually initiate a scram.
2.0 EVALUATION The Fermi-2 RPS currently includes three means of manually initiating a l
j reactor scram. These means are:
l l
Reactor Mode Switch Shutdown Position, l
Manual Scram,
" Backup Manual Scram.
During the staff's initial review of the manual scram system done in 1981, concerns were raised that the system did not meet the requirements of IEEE I
Standard 279-1971, Section 4.2 and 4.17. The licensee chose to modify the l
system and provide a backup manual scram system. The system consisted of a second set of pushbuttons that concurrently trip the power feed to each division l
l of the reactor trip system. This design was different from the Generic Electric I
design in 1981 which initiates a manual backup scram by opening logic contacts in the reactor trip system. The backup manual scram breakers are wired electrically between the respective RPS system distribution cabinets and the associated half j
of the RPS logic cabinet.
Actuating the Backup Manual Scram causes the additional action of isolating the reactor from the main condenser by closing the Main Steam Isolation Valves (MSIV). This occurs because the isolation actuation logics are powered from common power supplies with the RPS and are also deenergized by the openinc of the Backup Manual Scram breakers. The concurrent MSIV isolation with Backup Manual Scram actuation is highly undesirable since it removes,the availability g9%![$$k
$/
g P
l 0
l j.
s,
. of the main condenser as a heat sink. During conditions when a manual scram is underway, but not completed, it is desirable that the main condenser be available as a heat sink in order to reduce the severity of the transient and to reduce challenges to the Safety Relief Valves.
To alleviate this problem, the licensee committed to complete the following RPS modifications during Fermi-2's first refueling outage:
- Removal of the current Backup Manual Scram function. The pushbutton operators from this function will be used for two additional Manual Scram channels (one for each trip system). Combined with the two existing i
channels this will result in each trip system having two channels for Manual Scram.
i
- Upgrade of the RPS capability of manually initiating a scrani co meet all regulatory and design requirements for redundancy. This upgrade will result in a similar configuration for the Reactor Mode Switch Position function, i.e., four channels with two channels in each trip system.
The elimination of the Back-up Manual Scram function from the RPS requires that the line items associated with the function be eliminated from Table 2.2.1-1, Reactor Protection System Instrumentation Setpoints; Table 3.3.1-1, Reactor Protection System Instrumentation; Table 3.3.1-2, Reactor Protection System Response Times; and Table 4.3.1.1-1, Reactor Protection System Instrumentation Surveillance Requirements. The description of the Backup Manual Scram function is also deleted from Bases Section 2.2.1, Reactor Protection System Instruments-tion Setpoints.
The Technical Specification change associated with the additions is to increase the Minimum Operable Channels per Trip System requirement of Table 3.3.1-1, Reactor Protection System Instrumentation, from one to two for these trip functions (ManualScramandReactorModeSwitchPosition). This will require both channels in each trip system to be normally OPERABLE in all OPERATIONAL CONDITIONS. The existing ACTIONS and Surveillance Requirements remain appropriate for the modified design. This proposal also brings Fermi-2 Technical Specifica-tions into agreement with the BWR 4 Standard Technical Specifications, which indicate a two channel per trip system requirement for the Manual Scram and Reactor Mode Switch Position Scram functions.
The design change to replace the Back-up Manual Scram function with two additional redundant Manual Scram channels and the associated Technical Specification changes act to enhance safety at Fermi-2. The new design provides an alternative method to meet the regulatory requirement for manual scram redundancy while avoiding the potentially undesirable effects of the MSIV isolation which occurs concurrently with the present Backup Mandal Scram design. The Technical Specification changes properly reflect the new design and are in accordance with BWR 4 Standard Technical Specification. Based on the above evaluation the staff finds the proposed changes to the TS to be acceptable.
~t
L v
i j
, p l
3.0 ENVIRONMENTAL CONSIDERATION
Pursuant to 10 CFR 51.21, 51.32 and 51.35, an environmental assessment and l
finding of no significant impact have been prepared and publish in the l
Federal Register on August 29, 1989 (54 FR35734). Accordingly, based upon j
the environmental assessment, we have determined that the issuance of this J
amendment will not have a significant effect on the quality of the human 3
environment.
4.0 CONCLUSION
We have concluded, based on the considerations discussed above, that (1) there I
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 1
this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: John Stang Date: September 1,1989 e
4
.e
.h'