ML20136G251

Application for Amend to License NPF-11,changing Tech Specs to Provide for CRD Charging Water Header Low Pressure Scram W/Trip Setpoint of Greater than or Equal to 1,157 Psig.Fee Paid

ML20136G251
Person / Time
Site:	LaSalle
Issue date:	11/13/1985
From:	Massin H COMMONWEALTH EDISON CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
Shared Package
ML20136G253	List: ML20136G251 ML20136G262
References
0761K, 761K, NUDOCS 8511220291
Download: ML20136G251 (4)

Text

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.' / - Commonwealth Edison

) one First National Plaza. Chicago. lilinois

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O ~7 Address Reply to: Post Office Box 767 (Q Chicago, filmois 60690 November 13, 1985 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

LaSalle County Station Unit 1 Proposed Amendment to Technical Specification for Facility Operating License NPF-ll CRD Charging Water Header Low Pressure Scram NRC Docket Nos. 50-373 References (a): NPF-ll License Condition 2.C.(15) Low Pressure in Pump Discharge of the Control Rod Drive (b): UFSAR Section 4.6.1 pages 4.6-9, 27, 32 (c): UFSAR.Section 7.2 pages 7.2-3,4,10,15 Section 7.A.2 pages 7.a.2-34,35,36, Table 7.2-1, Table 7.2-2 and Figure 7.2-4 (d): SSER #2 4.6.2, Control Rod System (e): SSER #7 7.2, Control Rod Drive Low Charging Pressure Scram

( f): J. Marshall Letter to H.R. Denton dated September 25, 1984 (g): A. Schwencer Letter to D.L. Farrar dated December 17, 1984

Dear Mr. Denton:

Pursuant to 10 CFR 50.59, Commonwealth Edison proposes to amend Appendix A, Technical Specification, to Facility Operating License NPF-11.

These changes _are being submitted for your staff's review and approval.

l Attachment f provides background and discussion. The proposed change is enclosed in Attachment B. The attached change has received both On-Site and Off-Site review and approval. We have reviewed this amendment request and find that no significant hazard,s consideration exists. Our review is documented in Attachment C.

Commonwealth Edison is notifying the State of Illinois of our request for this amendment 'by transmitting a copy of this letter and its I *tachments to the designated State Official. 8}

NDEE!? 8%Q, ff f/

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H. R. Denton November 13, 1985 The modification to install a reactor trip on low CRD discharge water header pressure will be performed during the first refueling outage and the amendment must be approved before startup for Cycle 2. This is currently scheduled for March, 1986. Adding this modification makes Unit 1 look like Unit 2, which is a human factors concern, and responds to NPF-ll License Condition 2.c.15.

In accordance with the requirements of 10 CFR 50.170, a fee remittance in the amount of $150.00 is enclosed.

Please direct any questions you may have concerning this matter to this office.

Three (3) signed originals and thirty-seven (37) copies of this transmittal and its attachments are provided for your use.

Very truly yours, H. L. Massin Nuclear Licensing Administrator 1m Attachments A: Background and Discussion B: Technical Specification Change to NPF-11 C: Evaluation of Significant Hazards Consideration cc: Region III Inspector - LSCS A. Bournia - NRR M. Parker - State of Ill SUBSCRIBED AND SWQR to beforg/me.".isj/31p day of "// hVAL/tc< ,1985 00b

~ Notary Puolic 0761K

ATTACHNENT A TECHNICAL SPECIFICATION CHANGE REQUEST LASALLE COUNTY STATION UNIT 1 CRD CHARGING WATER HEADER LOW PRESSURE SCRAM BACKGROUND The cuntrol rod drive (CRD) system provides high pressure charging water to the under-piston area of the control rod drive mechanisms to scram the reactor when required. If the charging water header pressure is lost, the individual scram accumulators provide a source of energy to perform the scram function. Check valver are located between the accumulators and the charging water header. These check valves maintain the accumulators pressurized following a loss of charging water pressure. If a check valve leaks after charging water pressure is lost, the accumulator pressure could decrease below the pressure required to insert the control rod if the reactor pressure is insufficient to provide a source of high pressure water to accomplish the scram function (startup and refueling modes).

There is a concern when the reactor vessel is at less than operating pressure that the control rod drive accumulators do not maintain adequate pressure for a period of time compatible with operator action if no control rod drive pump is operating (reference (d)). With the reactor at operating pressure, charging water pressure is not of concern because reactor pressure is sufficient to ensure adequate scram capability.

DISCUSSION To ensure that sufficient high pressure water is available for a scram in the startup and refueling modes, a reactor trip (SCRAM) on low CRD discharge water header pressure has been designed and will be installed during the first refueling outage in LaSalle County Unit 1 (references (a),

(b), (c) & (e)). An identical scram has already been installed and the l

Technical Specification Amendment submitted and approved on Unit 2, license NPF-18 (references (f) and (g)). The proposed Unit 1 Technical Specification change (Attachment (B)) provides for a Control Rod Drive charging water header low pressure SCRAM with a trip setpoint of greater than or equal to 1157 psig (allowable value 1134 psig) with a time delay of less than or equal to 10 seconds. This scram is active when the reactor mode switch is in the STARTUP or REFUEL positions (Operational conditions 2 L

and 5) . Surveillance requirement 4.1.3.5.b.2, to " measure and record the time that each individual accumulator check valve maintains the associated accumulator pressure above the alarm setpoint with no control rod drive pump operating", is no longer required because the worst case leakage rate of the l accumulator check valves still provides sufficient pressure to insert the control rods with the charging water header low pressure scram in effect.

L

The setpoints described in references (b), (c), and (e) were based on a design trip point of 1100 psig with various instrument and setpoint uncertainties added in to determine the trip setpoint and the allowable values. To arrive at the setpoints included in Attachment A (trip setpoint of 1157 psig with an allowable value of 1134 psig) the calibrated range of the pressure transmitter and trip units will be 500-1500 psig.

Revisions to references (b) and (c) to incorporate the setpoints described herein are in progress for Unit 2, and the Unit 1 revis!ons will be completed at the next appropriate update to the UFSAR after the first refuel when the modification is installed.

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