ML20249A845

Safety Evaluation Supporting Amend 120 to License NPF-43

ML20249A845
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Site:	Fermi
Issue date:	06/12/1998
From:	NRC (Affiliation Not Assigned)
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UNITED STATES g

g NUCLEAR REGULATORY COMMISSION s

WASHINGTON, D.C. 2066Mo01 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.120 TO FACILITY OPERATING LICENSE NO. NPF-43 DETROIT EDISON COMPANY FERMI 2 DOCKET NO. 50-341

1.0 INTRODUCTION

By letter dated May 20,1998 (NRC-98-0099), the Detroit Edison Company (DECO or the licensee) requested an amendment to the Technical Specifications (TS) appended to Facility Operating License No. NPF-43 for Fermi 2. The proposed amendment would revise the action statements in TS 3.1.3.1, " Control Rod Operability," associated with the scram discharge volume (SDV) vent and drain va!ves. The revised action statements were written to conform with these in TS 3.1.8 in NUREG-1433, Revision 1, " Standard Technical Specifications General Electric Plants, BWR/4," (STS).

Although the SDV vent outboard isolation valve, C1100F0010, is currently operable in accordance with TS, the licensee has recently observed signs of degradation during testing of the valve in accordance with Surveillance Requirement 4.1.3.1.4.a.1 and the Inservice Testing Program. The licensee initiated testing at an increased frequency (approximately every 7 days) in order to establish a trend in the rate of degradation. However, the licensee has indicated that it could not estabhsh a clear trend. DECO management has determined that it is prudent to rework the actuator for this valve before degradation causes the valve to failits testing. This action would allow a planned activity to take place. In order to replace the actuator, C1100F0010 would be isolated, p! acing the plant in TS 3.1.3.1, Action e. with an 8-hour allowed i

outage time. The licensee does not believe that the replacement of the actuator can be accomplished within the 8-hour limit (the best schedule based on scope and resource loading is 11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br />).

The licensee requested the proposed amendment be treated as an exigent amendment as i

discussed in Section 4.0 of this safety evaluation.

2.0 BACKGROUND

The SDV is a volume of header piping that connects to each hydraulic control unit and drains into an instrument volume. There are two SDVs (headers) and two instrument volumes each receiving approximately one half of the control rod drive (CRD) discharges. The two instrument volumes are connected to a common drain line with two valves in series. Each header is connected to a common vent line with two valves in series. The header piping is sized to receive and contain all the water discharged by the CRDs during a scram.

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o. The SDV vent and drain valves are normally open, allowing any accumulated water in the SDV to be discharged to ensure that sufficient volume is available at all times to allow a complete scram. During a scram, the SDV vent and drain valves close to contain reactor water (coming from the CRDs) within the SDV. Because the SDV is outside the containment, the SDV vent and drain valves also perform a containment isolation function after a scram.

The design-basis accident and transient analyses assume all of the control rods are capable of scramming. The acceptance criteria for the SDV vent and drain valves are that they operate automatically to:

a.

Close during a scram to limit the amount of reactor coolant discharged so that adequate core cooling is maintained and offsite doses remain within the limits of 10 CFR Part 100; and b.

Open on a scram reset to maintain the SDV vent and drain paths open so that there is sufficient volume to accept the reactor coolant discharged during a scram.

The SDV is designed with additional features intended to ensure that a sufficient volume remains in the SDV to accept the reactor coolant discharge from a full core scram. An alarm actuates if the level in the SDV instrument volume exceeds a specified value. The alarm wams the operators that water is accumulating in the instrument volume, in addition, a reactor scram is automatically initiated if the water level in the SDV instrument volume exceeds a (higher) specified setpoint. This setpoint is chosen so that all control rods are inserted before the SDV has insufficient volume to accept the reactor coolant discharge from a full core scram.

3.0 EVALUATION The licensee proposed to revise TS 3.1.3.1, Action Statements d. and e., based on the STS.

The current Action Statement d. reads:

With one scram discharge volume vent valve and/or one scram discharge volume drain valve inoperable and open, restore the inoperable valve (s) to OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or be in at least HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

The revised Action Statement d. would read:

- With one or more scram discharge volume vent or drain lines with one valve inoperable, restore the inoperable valve (s) to OPERABLE status within 7 days, or be in at least HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

In addition, a new footnote (***) would be added to the action statement. This footnote would

. read:

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- Separate Action entry is allowed for each SDV vent and drain line.

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3,7 4.

i When one SDV vent or drain valve is inoperable in one or more lines,'the valves must be restored to operable status within 7 days. With one primary containment isolation valve inoperable in a penetration,' TS 3.6.3,

• Primary Containment Isolation Valves," requires that, within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, the hcensee either restore the valve to operable status or isolate the affected penetration. TS 3.6.3 also allows the licensee to unisolate the line under administmtive control.

- This provision would allow the licensee to periodically drain and vent the SDV. The staff.

considers the 7-day completion time reasonable given the alarms to wam the operators about increasing SDV instrument volume level and an automatic scram which actuates before the SDV has insufficient volume to accept the reactor coolant discharge from a full core scram.

Therefore, the staff concludes that this change is acceptable.

The current Action Statement e. reads:

Wdh any scram discharge volume vent valve (s) and/or one scram discharge volume drain valve (s) otherwise inoperable, restore the inoperable valve (s) to OPERABLE status within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> or be in at le.ast HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

The revised Action Statement e would read:

Wdh one or more scram discharge volume vent or drain lines with both valves inoperable, isolate the associated line within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />"", or be in at least HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

A new footnote ("") would be added to the action statement. This footnote would read:

An isolated line may be unisolated under administrative control to allow draining and venting of the SDV.

In addition, the *" footnote discussed above would be added to Action Statement e.

If both valves in a line are inoperable, the line must be isolated to contain the reactor coolant during a scram. When a line is isolated, the potential for an inadvertent scram due to high SDV level is increased. Action Statement e. is modified by the "" footnote that allows periodic' draining and venting of the SDV when a line is isolated. During these periods, the line may be unisolated under administrative control. This allows any accumulated water in the 'ine to be drained to preclude a reactor scram on SDV high level. This is acceptable since the administrative controls ensure the valve can be closed quickly, by a dedicated operator, if a scram occurs with the valve open. The current TS 3.6.3 already provides a similar provision.

The 8-hour completion time to isolate the line is based on the low probability of a scram occurring while the line is not isolated and unlikelihood of significant CRD seal leakage.

However, if applicable, the 4-hour time limit in TS 3.6.3 to repair the valve or isolate the penetration must also be met. The staff concludes that this change is acceptable.

L For both Actions d. and e., if the required action and associated completion time _is not met, the plant must be brought to a mode in which the limiting condition for operation does not apply. To

-o achieve this status, the plant must be brought to at least Mode 3, " Hot Shutdown," within

.12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The allowed completion time of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is reasonable, based on operating experience, to reach Mode 3 from full power conditions in an orderly manner and without challenging plant systems. The current TS 3.1.3.1 contains the same requirement.

. Based on the information discussed above, the staff concludes that the proposed changes are acceptable.

4.0 EXIGENT CIRCUMSTANCES

The Commission's regulations,10 CFR 50.91, contain provisions for issuance of amendments where the Commission finds that exigent circumstances exid, in that a licensee and the -

Commission must act quickly and that time does not permit the Commission to publish a Federal Register notice allowing 30 days for prior public comment. The exigency exists in this case in that one of the SDV vent valves is degrading and the current TS action statement does not allow adequate time to effect repairs to the valve. Either an outright failure of the valve or attempts by the licensee to repair the valve before it fails could lead to a plant shutdown.

The licensee was unable to make a more timely application because it only recently concluded that the valve might fail testing at any time and that rework in the near future would be prudent.

The licensee evaluated the time required to rework the valve and estimated that the work would take 11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br />. However, unforeseen problems could extend that time. Because the time required for the work exceeds the time allowed by the action statement, the licensee decided to request an amendment to change the action statement using the improved standard technical specifications as a guide. The licensee submitted the amendment request within a few days of the time it decided to make the request.

Accordingly, the Commission has determined that exigent circumstances exist pursuant to 10 CFR 50.91(a)(6)(i)(A) and could not have been avoided, that the submittal of information was timely, and that the licensee did not create the exigent condition.

5.0 FINAL NO SIGNIFICANT HAZARDS CONSIDERATION

S DETERMINATION The Commission's regulations in 10 CFR 50.92(c) state that the Commission may make a final determination that a license amendment involves no significant hazards consideration if operation of the facility in accordance with the proposed amendment would not (1) involve a significant increase in the probability or consequences of an accident previously evaluated, (2) create the possibility of a new or different kind of accident from any accident previously evaluated, or (3) result in a significant reduction in the margin of safety. The NRC staff has made a final determination that no significant hazards consideration is involved for the proposed amendment and that the amendment should be issued as allowed by the criteria contained in 10 CFR 50.91. The NRC staff's final determination is presented below.

1. The change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

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The proposed change will allow operation with one valve in one or more SDV vent or drain line(s) to be inoperable for any reason for a period of 7 days. The SDV vent and drain valves.

are not considered to be an initiator for any previously analyzed accident. Therefore, this -

- change does not involve a significant increase in the probability of any accident previously evaluated. Isolation capability is maintained for the short period the inoperable valve may not be capable of performing its function because redundant operable isolation valves will be -

available in each vent and drain line. The ability of the SDV vent and drain valves to limit the amount of water discharged during scram so that adequate core cooling and offsite doses remain within 10 CFR Part 100 limits is maintained. Therefore, this change does not involve a significant increase in the consequences of an accident previously evaluated.

' The change would also allow continued operation with one or more SDV vent or drain lines with both valves inoperable provided the line(s) are isolated within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> and allow the line(s) to be E

unisolated under administrative controls to vent or drain the affected SDV. The SDV vent and drain valves are not considered to be an initiator for any previously analyzed accident and, therefore, these changes do not involve a significant increase in the probability of any previously evaluated accident. With the vent or drain lines isolated, the accident containment isolation function is maintained. The administrative control provision allows the lines to be unisolated to preclude an unnecessary reactor trip on high SDV level and to ensure sufficient volume is available to accept the reactor coolant discharged during a scram. The administrative controls also provide for prompt action to isolate the line(s), if necessary, should

- a scram occur while the valve is open. Because the intended function is maintained, these changes do not involve a significant increase in the consequences of an accident previously evaluated.

2. The change does not create the possibility of a new or different kind of accident from any accdont previously evaluated.

The proposed changes do not involv6 sny physical modifications to the plant systems, structures, or components or significant sanges in the way the plant is operated. Therefore, the proposed changes do not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. The change does not involve a significant reduction in the margin of safety.

l The proposed changes to Action Statement d. would allow operation with one valve in one or more SDV vent or drain line(s) to be inoperable for any reason for a period of 7 days. The automatic scram on high SDV level (TS 3.3.1, Table 3.3.1-1, Functional Unit 8) ensures the SDV does not fill beyond the capacity needed to ensure a complete scram. The primary containment isolation function can be maintained by the redundant valve in each of these lines.

Also, the length of time a valve in an SDV drain or vent line can be inoperable is limited to

7. days. The probability of a scram occurring while the valve (s) are inoperable is low.

Therefore, the proposed change does'not involve a significant reduction in the margin of safety.

The proposed changes to Action Statement e. would allow continued operation with SDV vent or drain lines 'with both valves inoperable if the affected lines are isolated within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. With -

the lines isolated the pnmary containment isolation function is maintained. The provision that w-mau.

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6-permits the lines to be unisolated under administrative control to vent and drain the SDV -

ensures that an unnecessary reactor scram on SDV high level will not occur. The provision also ensures the lines that wJ unisolated under administrative controls can be promptly -

isolated. These provisions ensure that sufficient SDV volume is maintained to ensure a complete reactor scrar.1 and that primary containment integrity is maintained.

Therefore, the proposed change does not involve a significant reduction in the margin of safety.

6.0 STATE CONSULTATION

in accordance with the Commission's regulations, the Michigan State official was notified of the proposed issuance of the amendment. The State official had no comments.

7.0 ENVIRONMENTAL CONSIDERATION

i The amendment changes a requirement with respect to the use of a facility component located within the restricted area as defined in 10 CFR Part 20. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has made a final finding that the amendment involves no significant hazards consideration. Accordingly, the 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 the smmidment.

8.0 CONCLUSION

The Commission has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the i

Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributor: Andrew Kugler-Date: June 12, 1998

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