ML20078A799

Safety Evaluation Supporting Amends 202 & 180 to Licenses DPR-53 & DPR-69,respectively

ML20078A799
Person / Time
Site:	Calvert Cliffs
Issue date:	01/11/1995
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20078A791	List: ML20078A788 ML20078A799
References
NUDOCS 9501250146
Download: ML20078A799 (6)

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sa nta p-4 UNITED STATES NUCLEAR REGULATORY COMMISSION f

WASHINGTON, D.C. 20006 4001

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENOMENT N0. 202 TO FACILITY OPERATING LICENSE NO. DPR-53 Als AMENOMENT NO.180 TO FACILITY OPERATING LICENSE' NO. DPR-69 BALTIMDRE GAS AND ELECTRIC COMPANY CALVERT CLIFFS NUCLEAR POWER PLANT. UNIT NOS. 1 AND 2 DDCKET NOS. 50-317 AND 50-318

1.0 INTRODUCTION

By letter dated September 23, 1994, the Baltimore Gas and Electric Company (the licensee) submitted a request for changes to the Calvert Cliffs Nuclear Power Plant, Unit Nos. I and 2 Technical Specifications (TSs). The' requested changes would revise the Unit 2 Shutdown AC Sources TSs to increase the allowed outage time (A0T) to allow a one-time extension from 7 to 14 days for the dedicated Class IE emergency power sources and would also revise the Unit I control room emergency ventilation system (CREVS) TSs to allow a one-time extension from 7 to 30 days to the A0T for one train inoperable during the 1995 Unit 2 refueling outage.

These one-time extensions of the specific A0Ts are necessary to support the modifications scheduled for the onsite electrical power distribution system in response to the station blackout (SBO) rule and the upgrade of the No. 21 emergency diesel generator (EDG).

j Currently, Calvert Cliffs Nuclear Por Plant (CCNPP) uses three EDGs to provide emergency onsite power supply. These EDGs are designated as No. 11 EDG, No. 21 EDG, and No. 12 EDG. Normally, No. 11 EDG is dedicated to Unit 1, No. 21 EDG is dedicated to Unit 2, and No. 12 EDG is the " swing" EDG which is capable of powering one emergency bus on either unit. Offsite AC power is provided by three independent 500 kV transmission lines which provide offsite power to the units during nonnal operations as well as during startup and shutdown, and a 69 kV line from Southern Naryland Electric Cooperative (SMECO) which is also capable of supplying the power for all required safe shutdown loads for both units.

In response to the station blackout rule, tne licensee l

plans to modify the CCNPP electrical power distribution system to include the tie-in of an alternate f.C (AAC) diesel generator and to upgrade the No. 21 EDG to increase its electrical output during the 1995 Unit 2 outage.

In addition, CCNPP has a common control room for the two units. The CREVS consists of two redundant trains designated as No. 11 CREVS and No. 12 CREVS.

No. 11 CREVS receives power from Unit I through 4 kV Bus No. 11 with the No.

11 EDG used as the emergency power supply and No. 12 CREVS receives power from 9501250146 950111 PDR ADOCK 05000317 P

PDR

, Unit 2 through 4 kV Bus No. 24 with the No. 21 EDG used as the emergency power supply. During past outages, when the No. 21 EDG was not available as an emergency power supply, the No. 12 EDG was used as the emergency power supply for 4 kV Bus No. 24. The licensee stated that the capability to align the No. 12 EDG to 4 kV Bus No. 24 will be removed prior to the work scheduled to be perfonned to upgrade the No. 21 EDG. This will result in the No. 12 CREVS not having a safety-related emergency power supply during the period of the No. 21 EDG upgrade. However, Unit 1 is expected to be at full power during the time required to upgrade the No. 21 EDG which is expected to last about 30 4

days. With Unit 1 operating in Nodes 1 through 4, the current TSs require both trains of the CREVS (Nos.11 and 12) to be operable and one train is allcwed to be inoperable for up to 7 days. Without the requested one-time extension of the A0T for the Unit 1 CREVS from 7 days to 30 days, the scheduled modifications to the No. 21 EDG would require a dual unit 30-day outage.

2.0 EVALUATION A.

Unit 2 Dedicated Class IE Emergency Power Source A0T extension request. l As previously noted, the work scheduled for the 1995 Unit 2 refueling outage will consist of cutting the connection from the No. 12 EDG to 4 kV Bus No. 24 and installing a temporary splice box so that the No.12 EDG will continue to be able to " swing" to 4 kV Bus No. 21. The No. 12 EDG will be rendered inoperable until the installation of the temporary splice box is completed.

Unit 1 is expected to be at full power during this time period. Therefore, the No.11 EDG will be aligned to 4 kV Bus No.11 and the No. 21 EDG will be aligned to 4 kV Bus No. 14 so that Unit I will have the two required safety-related EDGs to support power operation.

Installation of the temporary splice box is scheduled to occur when the No.12 EDG is removed from service for its 18-month inspection.

It could take up to 14 days, which is longer than the 7-day A0T currently allowed by the shutdown TSs 3.8.1.2.b and 3.8.2.2.b for the shutdown unit to be without a qualified safety-related EDG. Thus, the licensee is requesting a one-time extension of the Unit 2 A0T. The current restrictions in Action Statement 3.8.1.2.b and 3.8.2.2.b will remain in effect until the temporary splice box is installed and the No.12 EDG is returned to operable status.

l Specifically, the requested TS change is to add the following note to TSs l

3.8.1.2 and 3.8.2.2 of the Unit 2 TSs.

t During the 1995 Unit 2 refueling outage, an emergency diesel generator l

shall be operable and aligned to provide power to an emergency bus within fourteen days.

During the temporary splice box installation, loss of offsite power to the shutdown unit is of concern. The probability of a loss of offsite power during the 14 days that the No.12 EDG is out-of-service is very low because of the reliability and redundancy of the offsite power sources. As

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. noted,there are four independent offsite power sources, the three 500 kV transmission lines and the 69 kV SMECO line, any one of which can provide for j

the safe shutdown loads of both units.

The potential for a loss of offsite power due to severe weather has been considered. The 500 kV transmission lines and towers are designed to withstand winds of 100 mph. Winds of this velocity could be from a hurricane or a tornado.

The incidence of hurricanes of 100 mph magnitude in the CCNPP area is very low (only one in recorded history). Tornadoes can occur at any time, given the right meteorological conditions. Tornadoes with wind velocities in excess of 100 mph in the CCNPP area are also very rare.

It is extremely unlikely that a single tornado would strike all three 500 kV transmission lines and the SMECO line. At the site, the 500 kV lines are i

overhead while the SMECO line is underground. A tornado at the site may damage the 500 kV lines, but would not affect the SMECO line. Should the site or the offsite power circuit's right-of-way be threatened by severe weather, the licensee's Emergency Response Plan Implementation Procedures require actions which lead to placing both units in a safe condition depending on the severity of the weather.

In addition, the temporary diesel generator that is already required by Action Statements 3.8.1.2.b and 3.8.2.2.b will be available during the installation of the temporary splice box. Action Statements 3.8.1.2.b and 3.8.2.2.b also require a minimum of two offsite power circuits; suspending all operations involving core alterations, positive reactivity changes, movement of irradiated fuel, and movement of heavy loads over irradiated fuel; and establishing containment penetration closure. These will continue to apply during the 14-day period. Furthermore, reduced inventory conditions for the reactor coolant system will be prohibited during the 14-day period.

Two accidents have been evaluated for a unit in Mode 5 and 6.

They are a fuel handling accident and a boron dilution event. The fuel handling accident is precluded because no core alterations or other movement of irradiated fuel will be allowed to take place during the requested extension. Containment closure is also required as a precaution. The boron dilution event is rendered unlikely in that positive reactivity changes will be suspended during the requested A0T extension.

In summary, the following compensatory measures will be invoked during the modification process:

1, Planned maintenance will be prohibited on two of the three 500 kV lines and associated relaying and devices within the switchyard during the time that the No. 12 EDG is out-of-service.

2.

The SMECO 69 kV line availability will be verified once per shift.

3.

A temporary diesel generator will be installed to provide a backup onsite power source to support the safety-related loads of the shutdown unit.

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CCNPP Emergency Response Plan requires that certain actions. be taken, up to and inc'uding shutdown of the units, on the approach of a severe stors, such as hurricane.

5.

Core alterations; positive reactivity insertions; movement of irradiated fuel; and movement of heavy loads over irradiated fuel will be prohibited while the No. 12 EDG is out-of-service for the temporary splice box installation.

6.

Containment penetration closure will be established to ensure that adequate margin of safety is maintained.

7.

Reduced inventory conditions of the reactor coolant system will be prohibited during the time the No.12 EDG is out-of-service.

Based on the above, we have determined that a one-time extension of the 7-day A0T to 14-day A0T period would not have an unacceptable effect on the overall safety of CCNPP.

B.

Unit 1 CREVS A0T extension request.

The following TS requirements are currently applicable to Unit 1.

During plant operation at Modes 1, 2, 3, and 4, TS Section 3.7.6.1, in part, currently requires that:

With one filter train inoperaple, restore the inoperable train to a.

OPERA 8LE status within 7 days or be at least HOT STANOBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

1 b.

With one air conditioning uni} inoperable, restore the inoperable unit to OPERABLE status wi?.hin 7 days or be at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLE SHUTDOWN within the fc110 wing 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

l The licensee proposes to modify the above requirements on a one-time basis at l

the marked spaces (*) by inserting the following:

During the No. 21 EDG upgrade in the 1995 Unit 2 refueling outage, the time to i

restore No. 12 filter or air conditioning unit to OPERABLE status may be

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extended to 30 days (for loss of emergency power only) if the following is performed:

1.

A temporary diesel generator shall be demonstrated available by e

starting it at least once per 7 days.

2.

If ACTION 1 is not met, restore compliance with the ACTION within 7 days or be in at least HOT STAND 8Y within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

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l As previously noted, the work on the No. 21 EDG upgrade is scheduled to be performed during the Unit 21995 outage and is expected to be completed within 30 days. During this period, the loss of control room habitability resulting from the loss of power to the CREVS is of concern. The CREVS is required to maintain the control room temperature below a specified limit and to filter the control room air in the event of a radioactive release.

The licensee indicated that the capability to align the No. 12 EDG to 4 kV Bus No. 24 will be renovad prior to the No. 21 EDG upgrade and 4 kV Bus No. 24 also must be deentergized for 4 days to allow bus work for the tie-in of the AAC diesel generator. Therefore, the No. 12 CREVS will not have a safety-related emergency power supply during the No. 21 EDG upgrade period. However, a temporary die',el generator will be connected to 4 kV Bus No. 24 to assure that AC power would be available to the No.12 CREVS.

In addition, during this upgrade, period, planned maintenance will be prohibited on three of the above cited four offsite power sources.

Thus, the No.11 CREVS will have both its normal and emergency power sources available during this upgrade period. The No.12 CREVS will also have its normal power source available, except for a brief period (e..g., when the 4 kV Bus No. 24 must be deenergized to allow bus work for the tie-in of the AAC diesel generator) as permitted under the current TS.

Loss of all power to both trains of the CREVS would require loss of all offsite power sources, the failure of the No. 11 EDG to start, and the failure of the temporary diesel generator to start. Consequently, the licensee concluded that the probability of a loss of both trains of the CREVS resulting from loss of all power supply sources during the No. 21 EDG upgrade period is very low.

Based on the above, we concur with the licensee's conclusion that the probability of a loss of both trains of CREVS resulting from the loss of power is very low during the upgrade period. We have further determined that this proposed one-time TS change will not result in undue risk.

3.0 SUP9tARY Therefore, the NRC staff has concluded that the proposed one-time extensions of the A0Ts, as detailed above, are acceptable.

Specifically, during the Unit 2 1995 refueling outage, Unit 2 TSs 3.8.1.2.b and 3.8.2.2.b will be modified to extend the A0T from 7 days to 14 days and Unit 1 TSs 3.7.6.1.a and.b will be modified to extend the 40T from 7 days to 30 days. The Unit 1 TSs will also require that a temporary diesel generator shall be demonstrated to be available by starting it at least once per 7 days and, if this action cannot be met within 7 days, the unit must be taken to HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

4.0 STATE CONSULTATION

In accordance with the Commiission's regulations, the Maryland State official was notified of the proposed issuance of the amendments. The State official had no comments.

5.0 ENVIR0 MENTAL CONSIDERATION The amendments change a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements. The NRC staff has determined that the amendments involve 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 ne significant increase in individual or cumulative occupational radiation exposure. The Commiission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (59 FR 53935). Accordingly, the amendments meet 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 amendments.

6.0 CONCLUSION

The Commission has concluded, based on the considerations discussed above, that:

(1) there is reasonable assurance that the health and safety of the i

public will not be endangered by operation in the proposed manner, (2) such j

activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common i

defense and security or to the health and safety of the public.

Principal Contributors:

S. Saba and D. Shum Date: January 11, 1995 i

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V January 11, 1995 Mr. Robert E. Denton Vice President - Nuclear Energy Baltimore Gas and Electric Company Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702

SUBJECT:

ISSUANCE OF AMENDMENTS FOR CALVERT CLIFFS f JCLEAR POWER PLANT, UNIT NO. 1 (TAC NO. M90500) AND UNIT NO. 2 (TAC NO. M90501)

Dear Mr. Denton:

The Commission has issued the enclosed Amendment No.202 to Facility Operating License No. DPR-53 and Amendment No.180 to Faci'ity Operating License No.

DPR-69 for the Calvert Cliffs Nuclear Power P1 int, Unit Nos. I and 2, respec-tively. The amendments consist of changes tc the Technical Specifications (TSs) in response to your application transmitted by letter dated September 23, 1994.

The amendments revise the Unit 2 Shutdown AC Power Sources TSs to permit a one-time increase in the allowed outage time (A0T) from 7 to 14 days for the dedicated Class IE emergency power system and revise the Unit I control room emergency ventilation system TSs to permit a one-time increase in the A0T from 7 to 30 days. These one-time extensions are necessary to support modifications scheduled to be implemented during the upcoming 1995 Unit 2 refueling outage.

A copy of the related Safety Evaluation is enclosed. A Notice of Issuance will be included in the Commission's next regular biweekly Federal Reaister notice.

Sincerely, Original signed by Daniel G. Mcdonald, Senior Project Manager Project Directorate I-l Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket Nos. 50-317 and 50-318

Enclosures:

1.

Amendment No. 202 to DPR-53 l

2.

Amendment No.180 to DPR-69 3.

Safety Evaluation cc w/encls:

See next page

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