ML20247K764
| ML20247K764 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 05/19/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20247K762 | List: |
| References | |
| NUDOCS 8906020008 | |
| Download: ML20247K764 (3) | |
Text
__
,,y Ch UNITED STATES g
NUCLEAR REGULATORY COMMISSION.
E 7,
i WASHINGTON, D. C. 20S55
/
e SAFETY EVALUATION BY-THE OFFICE OF NUCLEAR REACTOR REGULATION' RELATED TO AMENDMENT NO.33 TO FACILITY OPERATING LICENSE NO. NPF-43 1
DETROIT EDIS0N COMPANY WOLVERINE POWER SUPPLY COOPERATIVE. INCORPORATED FERMI-2 DOCKET NO. 50-341
1.0 INTRODUCTION
I By letter dated March 10, 1988, theDetroitEdisonCompany(DEcoorthelicensee) requested amendment to the Technical Specifications (TSs) appended to Facility Operating License No. NPF-43 for fermi-2. The proposed amendment would revise TS Section 4.3.8.2.c to allow a'one-time extension to the disassembly and inspection interval for the turbine overspeed protection system valves.. The valves involved include the turbine control valves, high pressure turbine stop valves,' low pressure turbine intercept valves, and the low pressure turbine stop valves. These tests will become overdue after May 20, 1989, and the amendment would allow extension until the first refueling outage, scheduled to begin in September 1989.
2.0.~ EVALUATION Technical Specification 4.3.8.2.c requires that every 40 months at least one turbine control valve, high pressure turbine stop valve, low pressure turbine intercept valve, and low pressure turbine stop valve be disassembled, and a visual and surface inspection performed of the valve seats, disks, and stems to verify no unacceptable flaws or excessive corrosion _are 3 resent. An additional 25 percent may be added to the 40 month interval per Tecinical Specification 4.0.2.a.:resulting in a latest due date on this surveillance of May 20, 1989.
Performance of the surveillance requires the plant to be shut down. Deco estimated that the dismantling and inspection of one turbine control valve, one high pressure stop valve, and one low pressure turbine intercept valve will take 1340 man hours each and one low pressure turbine stop valve 485 man hours.
-There are no outages planned between now and the first refueling outage.
A low power license was issued for Fermi-2 on March 20, 1985.. Use of this date for the commencement of the surveillance interval results in the May 20, 1989 maximum due date. Initial criticality was achieved on June 21, 1985. Upon entry into Operation Condition 2, Specification 4.3.8.2.c first became applicable.
The first turbine roll was performed on September 26, 1985.
By the commencement of the first refueling outage, the valves will have experienced operating conditions for approximately 24 months. Normally, 2 full operating cycles of fbOOOk 1
o i
wear are experienced before this surveillance is due to be performed.
Due to Fermi's extended startup test program, the surveillance becomes due before completion of even this first operating cycle.
Therefore, this one-time extension is needed.
The purpose of the surveillance is to assess the condition of the valves to verify that no unacceptable flaws or excessive corrosion will prevent them from closing when needed to prevent an overspeed condition.
Valve mechanical behavior during routine operation has been good.
There is no indication that the valve l
seats have corroded which could be evidenced by problems in keeping the unit on the turning gear during startup preparations.
The valves closed properly during the trip experienced February 26, 1989.
Weekly, each of the valves is fully cycled.
This test is unaffected by this proposed one-time extension of the i
dismantling surveillance.
There have been no situations detected where the valves would not fully close that could be attributed to actual valve problems.
The current and past problems that have been. experienced with turbine valves have been due to actuator, circuitry, or test problems, not valve degradation.
l The required dismantling and inspection of the valves is to find problems with
- f the valves themselves.
A mechanical and the electrical overspeed trip system were last successfully l
tested on August 7, 1988.
This testing confirmed that the turbine is protected j
from an overspeed condition, as required by Technical Specifications.
The manufacturer of the turbine, English Electric, was contacted on this matter by DECO.
Their representative stated that they concur with the postponement of the inspection to the first refueling outage.
The basis of the Standard Technical Specification involves maintaining turbine j
overspeed protection to reduce the hazard of turbine missiles.
This function is also discussed in the Standard Review Plan Sections 3.5.1.3 and 10.2.
The bases for the Fermi-2 Turbine Overspeed Protection System specifications states, in part, " Protection from turbine excessive overspeed is not required to protect safety-related components, equipment or structures.
However it is included in order to improve overall plant reliability." Since the overspeed protection system is not needed to protect safety-related equipment or to safely shutdown in the event of a turbine overspeed condition, extension of the surveillance interval cannot adversely affect safety-related equipment.
A discussion of the I
turbine missile evaluation is contained in the Updated Final Safety Analysis Report, Section 10.2.3.
The Standard Review Plan, Section 10.2 states that at approximately 3 year intervals, during refueling or maintenance shutdowns coinciding with the inservice inspection schedule required by Section XI of the ASME Code for reactor components, as least one of each type of valve should be dismantled and examined.
Fermi-2's Safety Evaluation Report states that this program is acceptable and will be included in the Fermi-2 Technical Specifications.
Thus, the anticipated interval involved performance approximately every 3 years during refueling outages or maintenance shutdowns coincident with the inservice inspection schedule.
The inservice inspection schedule required by Section XI of the ASME Code initialized at commercial operation, thus 3 years from this time would not be until the second refueling outage.
The proposed one-time extension to the l
first refueling outage is within the program reviewed as acceptable.
l l
To summarize, there is no safety issue involved in extending on a one-time basis the surveillance interval for the dismantling and inspection of turbine valves until the first refueling outage because:
all tests performed to date have indicated no problems with the valves l
themselves, the total period of valve exposure to operating conditions is well within the, expected number of months exposure anticipated for future surveillance intervals, given average availability, the vendor has indicated agreement with the extension, and j
protection from turbine excessive overspeed is not required to protect f
safety-related components, equipment or structures.
i Based on the above evaluation, the staff finds the proposed changes acceptable.
I
3.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes in surveillance requirements. We have determined that this amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents which may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding. Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.
4.0 CONCLUSION
1 We have concluded, based on the considerations discussed above, that (1)
)
there is reasonable assurance that the health and safety of the public will l
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 this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributo Lynn 911y i
Date: May 19, 1989 l