ML20215L221

Forwards Response to Generic Ltr 86-06, Implementation of TMI Action Item II.K.3.5,Automatic Trip of Reactor Coolant Pumps. Subcooled Margin Monitor Instrument Uncertainty Not Provided,Since Addl Calculations Required

ML20215L221
Person / Time
Site:	Calvert Cliffs
Issue date:	10/23/1986
From:	Tiernan J BALTIMORE GAS & ELECTRIC CO.
To:	Thadani A Office of Nuclear Reactor Regulation
References
TASK-2.K.3.05, TASK-TM GL-86-06, GL-86-6, NUDOCS 8610280534
Download: ML20215L221 (7)

Text

B ALTIMORE GAS AND ELECTRIC CHARLES CENTER P. O. BOX 1475 BALTIMORE, MARYLAND 21203 JOSEPH A.TIERNAN Vict PReslotNT NUCLEAR ENERGY October 23,1986 U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D. C. 20555 ATTENTION: Mr. Ashok C. Thadani, Director PWR Project Directorate #8 Division of PWR Licensing-B

SUBJECT:

Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 Response to Generic Letter 86-06, " Implementation of TMI Action item II.K.3.5, Automatic Trip of Reactor Coolant Pumps"

REFERENCES:

(a) Generic Letter 86-06, implementation of TMI Action Item II.K.3.5, " Automatic Trip of Reactor Coolant Pumps," dated May 29,1986 (b) Letter from Mr. J. A. Tiernan (BGocE), to Mr. A. C. Thadani (NRC), dated October 14,1986, same subject (c) Combustion Engineering Nuclear Power Systems Division,

" Justification of Trip-Two/ Leave-Two Reactor Coolant Pump Trip Strategy During Transients," (prepared for the C-E Owners Group) Combustion Engineering report CEN-268 (March 1934)

Gentlemen:

Reference (a) requested additional plant specific information regarding our trip-two/ leave-two procedures for small break Loss of Coolant Accidents (LOCA). As noted in Reference (b), we are unable to provide the Subcooled Margin Monitor's (SMM) instrument uncertainty with this response to Generic Letter 86-06. We have completed a series of preliminary calculations for the SMM's loop uncertainty. However, additional calculations are required to determine the influence of the pressure loop uncertainty on the SMM's calculation of subcooling for a wide range of primary temperatures. This is necessary to assure that the loop uncertainties calculated bound our expected operating temperature range during the events of concern (Small Break LOCA, Steam Line Break and Steam Generator Tube Rupture) for the trip two/ leave two scenario.

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8610280534 861023 i PDR ADOCK 05000317 P PDR

Mr. Ashok C. Thadani October 23,1986 Page 2 Our response to Generic Letter 86-06, less the SMM data, is provided as an attachment

to this letter. We will provide the SMM instrument uncertainty for normal and adverse containment conditions by November 24,1986.

Should you have any questions regarding this matter, we will be pleased to discuss them with you.

Very truly yours, JAT/LSL/dtm Attachment cc: D. A. Brune, Esquire

3. E. Silberg, Esquire S. A. McNeil, NRC T. Foley, NRC i

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d i ATTACHMENT 9

RESPONSE TO GENERIC LETTER 86-06 r The Calvert Cliffs Reactor Coolant Pump (RCP) trip strategies are identical for Units 1 and 2. Our procedures incorporate the RCP trip strategy (trip two/ leave two) outlined in Reference (c) with the following exceptions. The Combustion Engineering Owners Group (CEOG) methodology requires the first two RCPs be tripped at 1300 psia (indicated) and the remaining two RCPs be tripped once a positive identification of a Loss Of Coolant Accident (LOCA) condition has been made. Reference (c) based 1300 psia on a 1210 psia i nominal setpoint and a normal operating pressurizer pressure uncertainty of 45 psi.

! Calvert Cliffs procedures require the first two RCPs be tripped at 1725 psia (indicated)

and the remaining two RCPs be tripped at 1300 psia (indicated) if a LOCA condition j exists. For direct indication of a LOCA condition, the Calvert Cliffs RCP trip strategy uses steam generator pressure trends in addition to the parameters recommended by

Reference (c) which are Containment Radiation Alarms and Subcooling. The 1725 psia setpoint used to trip the first two RCPs was chosen because Safety Injection Actuation occurs at this point and provides an alarm which can key the operator to trip the first two RCPs.

The following responds to your request for additional information regarding plant specific instrumentation selection and uncertainties, and operator training and procedures:

f l 1. Identify the instrumentation to be used to determine the RCP trip setpoints, j including the degree of redundancy of each parameter signal needed for the criteria chosen.

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RESPONSE

! The parameters used to determine RCP trip setpoints are Pressurizer Pressure,

! RCS Subcooling, Containment Radiation, and Steam Generator Pressure. The l instrumentation used and degree of redundancy required for each parameter are listed in Table 1.

2. Identify the instrumentation uncertainties for both normal and adverse containment i conditions. Describe the basis for ti e selection of the adverse containment

! parameters. Address, as appropriate, local conditions such as fluid jets or pipe whip

l. which might influence the instrumentation reliability.

i RESPONSE:

A summary of uncertainties is shown below. The basis for selection of the adverse containment parameters was the Updated Final Safety Analysis Report, Tables 14.20-1, 12, 13, and 15. The effects from fluid jets and pipe whip were not considered due to the redundancy associated with each of these safety-related j instruments.

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ATTACHMENT RESPONSE TO GENERIC LETTER 86-06 INSTRUMENT UNCERTAINTY NORMAL ADVERSE CONTAINMENT CONTAINMENT INDICATION CONDITIONS CONDITIONS Pressurizer Pressure (psia)

PT-105 Loop 85.8 423.2 PT-102 Loop 19.7 105.5 High Range Containment Gamma Atonitors 3.16 3.16 (R/hr Between IE0andIEl)

The remaining pressurizer pressure indications available are all bounded by the PT-102 and PT-105 instrument loop uncertainties for both normal and adverse containment conditions.

3. In addressing the selection of the criterion, consideration of uncertainties associated with the CEOG supplied analyses values must be provided. These uncertainties include both uncertainties in the computer program results and uncertainties resulting from plant specific features not representative of the CEOG generic data group.

RESPONSE

Our pressurizer pressure trip two/ leave two setpoints, combined with instrument uncertainties, are conservative when compared to the CEOG nominal setpoint (1210 psia) for pressu Our high range containment radiation alarm's sensitivity is 10 giper ampspressure.

which is equivalent to one R/hr. Additionally, the alarm's setpoint falls within the range of 1-10 R/hr as required by Reference (c).

4. Identify all plant procedures (except for those concerning normal operations such as normal cooldown) which require RCP trip guidelines. Reference to the CEOG Emergency Procedure Guidelines is acceptable if endorsed by the licensee. Include training and procedures which provide direction for use of individual Steam Generators with and without operating RCPs.

ATTACHMENT RESPONSE TO GENERIC LETTER 86-06

RESPONSE

The plant procedures which require RCP trip guidelines are the Emergency Operating Procedures (EOP) listed below.

EOP-0 Post Trip Immediate Actions EOP-4 Excess Steam Demand Event EOP-5 Loss of Coolant Accident EOP-6 Steam Generator Tube Rupture EOP-8 Functional Recovery Procedure Of the EOPs listed, EOP-4,6 and 8 provide guidance for use of an individual Steam Generator with or without operating RCPs. Formal training on the above EOPs is established and includes the use of plant simulator scenarios which focus on the RCP trip strategy. These scenarios include tripping of either two or all four RCPs based on the event initiator and the use of an individual Steam Generator with or without operating RCPs.

O TABLEI INSTRUMENTATION USED FOR TRIP TWO/ LEAVE TWO REACTOR COOLANT PUMP OPERATING STRATEGY DEGREE OF REDUNDANCY AVAILABLE REQUIRED PARAMETER TRANSMITTER INDICATION RANGE (Note a) ,

Pressurizer PT-100X PIC-100X 1500-2500 psia Pressure PT-100Y PIC-100Y 1500-2500 psia Note (b) PT-102A PIC-102A 1500-2500 psia PT-102B PIC-102B 1500-2500 psia PT-102C PIC-102C 1500-2500 psia PT-102D PIC-102D 1500-2500 psia 2 PT-103 PIC-103 0-1600 psig PT-103-1 PIC-103-1 0-1600 psig PT-105A PI-105A 0-4000 psia PT-105B PR-105B 0-4000 psia Reactor TE-ll2CA Coolant TE-Il2CB System TE-ll2HA AE-Il Subcooling TE-Il2HB

( F) PT-105A Note (b) TE-122CA 1 TE-122CB TE-122HA AE-12 TE-122HB PT-105B Containment RE-5317A RI-5317A 10E0-10E8 1 Radiation RE-5317B RI-5317B 10EO-10E8 (R/hr)

Note (b)

Steam PT-1013-A PI-1013-A 0-1200 psia Generator PT-1013-B PI-1013-B 0-1200 psia Pressure PT-1013-C PI-1013-C 0-1200 psia Note (b) PT-1013-D PI-1013-D 0-1200 psia 2/Steans Generator PT-1023-A PI-1023-A 0-1200 psia PT-1023-B PT-1023-B 0-1200 psia PT-1023-C PI-1023-C 0-1200 psia PT-1023-D PI-1023-D 0-1200 psia

TABLE 1 INSTRUMENTATION USED FOR TRIP TWO/ LEAVE TWO REACTOR COOLANT PUMP OPERATING STRATEGY NOTE (a) The degree of redundancy required is based on our Technical Specifications 3.3.3.6 (Post-Accident Instrumentation) which state the minimum number of post-accident instrumentation channels required to be operable. This ensures that sufficient information is available on selected plant parameters to monitor and assess these variables following an accident.

This capability is consistent with the recommendations of Regulatory Guide 1.97, " Instrumentation for Light-Water-Cooled Nuclear Plants to Assess Plant Conditions During and Following an Accident," December 1975, and NUREG-0578, "TMI-2 Lessons Learned Task Force Status Report and Short-term Recommendations."

NOTE (b) The instrumentation listed in Table (1) is available for both Units 1 and 2.

The ranges and degree of redundancy required are also the same.

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