ML13330B464

Forwards Revised Justification for Continued Operation of Charging Pump Motor Rating

ML13330B464
Person / Time
Site:	San Onofre
Issue date:	02/02/1989
From:	Nandy F SOUTHERN CALIFORNIA EDISON CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
NUDOCS 8902030253
Download: ML13330B464 (7)

Text

Southern California Edison Company P. 0 BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 F. R. NANDY TELEPHONE MANAGER OF NUCLEAR LICENSING (818) 302-1896 February 2, 1989 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Gentlemen:

Subject:

Docket No. 50-206 Recertification of Charging Pump Motor Rating San Onofre Nuclear Generating Station Unit 1 By letter dated December 29, 1988, the report which documents the recertification of the charging pump motors to 700 hp and a service factor of 1.15 was provided to you. Also included with the letter was a justification for continued operation (JCO) of San Onofre Unit 1 with a rewound charging pump motor. During a telephone discussion with the NRC staff on January 13, 1989, an error in the cost options evaluation attached to the JCO as Enclosure 3 was identified. It was subsequently identified that the outage cost of $80K per day was incorrect and should have been

$250K per day. A revised Enclosure 3 indicating these changes is provided as Enclosure 1 to this letter.

There were actually two options available for the Cycle 10 refueling outage. Option 1 entailed rewinding the motor to its current rating at a cost of $173K and would have extended the outage from 10 to 14 days at an impact of $250K per day (approximately $2673K to $3673K total).

The motor could also have been rewound to a higher rating of 1000 hp at a cost of

$260K and would have extended the outage by approximately 28 days.

The second option entailed replacing the motor with a surplus motor at a cost of $242K and would have extended the outage for an unknown duration. The cost of $37.5K to install a new motor with an appropriate manufacturing lead time for the Cycle 11 refueling outage, compared to the Cycle 10 options, demonstrates the heavy penalty for an expedited schedule.that would have been incurred if the motor had been rewound or replaced during the Cycle 10 refueling outage.

Also, during the telephone discussion, the radiation qualification of the rewound motor, a Class B insulation system, was discussed. The staff reviewer requested that additional information on Class B insulation radiation withstand capability be provided. Enclosure 2 to this letter provides this information. It concludes that based on data from different sources, which included testing, the material within the rewound motor insulation is qualified for operation in its post-accident radiation environment.

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Document Control Desk

-2 It is also necessary to correct a statement which was included in our December 30, 1988 letter regarding the Seventh Edition of the Integrated Implementation Schedule (IIS).

On page 2 of the enclosure to the letter in the third paragraph it is indicated that the charging pump motors will be rewound (during the Cycle 11 refueling outage) as they reach the end of their qualified life. That is not correct. The south charging pump motor (G8B) will be either rewound or replaced during the Cycle 11 refueling outage. This is due to the fact that required environmental qualification documentation regarding the rewind process and materials is not available for-this motor. Review of the north charging pump motor (G8A) maintenance history reveals no rewind activity, therefore, its qualification is not suspect and the 40 year qualified life established by the Environmental Qualification Data Package (EQPD) is still applicable. However, SCE has committed to upgrade the safety injection system, pending NRC approval, during the Cycle 11 refueling outage and this may result in additional charging flow requirements which would necessitate rewinding or replacing both the charging pump motors to potentially a 1000 HP rating. In this case, both motors would be either rewound or replaced.

In order to verify that the qualification of other safety-related motors is not suspect due to past rewind activity, SCE will undertake an effort to review the operator's logs to identify any operational events which may have occurred involving motors on the EQ Master List which would have potentially led to a need to rewind the motor. If any potential events are identified, maintenance files for that period will be researched to verify that a rewind did not occur. This effort will be completed prior to return to service from the Cycle 10 refueling outage.

If you have any questions regarding this matter, please let me know.

Very truly yours, Enclosure cc: 3. B. Martin, Regional Administrator, NRC Region V F. R. Huey, NRC Senior Resident Inspector, San Onofre Units 1, 2 and 3

ENCLOSURE 1 Revised Enclosure 3 to the Justification for Continued Operation

ENCLOSURE 3 MEMORANDUM FOR FILE Page 1 of 3 February 1, 1989 DISCUSSION OF POTENTIAL COST/SCHEDULING IMPACT FACTORS" FOR REWIND OF THE SO1 G8B SOUTH CHARGING PUMP MOTOR In light of the indeterminate qualification status and associated JCO relating to the SO1 G8B motor rewind in

1972, the following discussion of cost and scheduling impact is. deemed necessary.

Potential Cycle 10 outage impact and costs are based on a rewind decision date of 10/25/88 (see page 3).

There are three basic options:

1)

Rewind existing motor

2)

Replace with surplus motors

3)

Purchase new motor for installation during cycle.11 outage Option 1: Rewind existing motor Rewinding can be further divided into two paths:

a)

Rewind motor during the Cycle 10 obtage to current rating (600/700 HP) at a capital cost of 173K. Potential outage impact of 10 to 14 day extension at 250k/day.

Total cost is estimated at 2673K to 3673K depending on outage impact.*

b)

Rewind. motor during the Cycle 10 outage to maximum allowed rating of 1000 HP at a capital cost of 260k and an estimated outage extension of 28 days at 250K/day.

Total estimated cost is 7260K.

Option 2: Replace with surplus 1000 HP motor Capital cost 242k.

Outage schedule impact unknown but there is a high potential for significant impact.

Note:.Rewinding to 600/700 HP during Cycle 10 still leaves the necessity of further rewind during Cycle 11 in order to accommodate increased charging flow requirements post Cycle 11 outage.

ENCLOSURE 3 PAGE 2 OF 3 Option 3: Purchase new 1000 HP,motor for installation during the cycle 11 outage.

A new motor is not available for the cycle 10 outage.

Capital cost 37.5k.

Summary:

Option 1 (a) 2673k to 3673k:

motor replacement (37.5k) still necessary during Cycle 11 outage.

Option 1 (b) --

7260k Option 2 242k. High probability of significant outage extension.

Option 3 37.5k.

==

Conclusion:==

Given the JCO conclusion of-no safety concern, the most reasonable

option, based on cost and scheduling, is to delay rewind.until the Cycle 11 outage.

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DISCUSSION OF SO1 SOUTH CHARGING PUMP MOTOR MATERIALS.RADIATION PROPERTIES PURPOSE:

To respond to an NRC request for further information on the basis for the conclusion that the materials used in the rewind of the S01 south charging pump motor are suitable for the applicable radiation environment of 4.0 E6 RADS.

DISCUSSION:

In addition to the Westinghouse conclusion that the materials could be expected to meet the 4.0 E6 RADS requirement, the following data from EPRI NP-2129, Radiation Effects on Organic Materials. in Nuclear Power Plants (November 1981) also supports operability to at least 4.0 E6 RADS (40 years normal lifetime plus 120 days post accident.TID).

Note that this data is for generic material properties and meant to cover a broad spectrum of material uses and forms.

These forms are not necessarily specific to the as-used forms of the materials within the rewound motor, but, because of their generic material nature, they are considered applicable to the rewound motor.

MATERIAL DATA AND REFERENCE Mica Not considered radiation sensitive Glass cloth 1.0 E8 RADS Epoxy 2.0 E8 RADS (NP-2129, p. 3-2)

Polyester 8.0 E6 RADS (NP-2129, p. 3-4; polyester resin listed)

Silicon rubber 5.0 E7 RADS (NP-2129, p. 3-32)

EPR 1.0 E7 RADS (NP-2129, p. 3-24)

These data and conclusions are further supported by WCAP 8587 AE 2,

where a large motor with Class B insulation and generically similar materials was tested and qualified to 5.0 E7 RADS.

Furthermore, Limitorque successfully tested commercial grade motors with Class B insulation systems to 2.0 E7 RADS (Limitorque report B-0003).

CONCLUSION:

Given the above data and the previously submitted evaluation and conclusion within the referenced

JCO, there is sufficient basis for concluding that the materials used in the SO1 south charging pump motor rewind are capable of withstanding the 4.0 E6 RADS radiation environment and will perform their safety function post accident, as required.