ML20153E953

Proposed Tech Specs Re Standby Liquid Control Sys

ML20153E953
Person / Time
Site:	Cooper
Issue date:	04/29/1988
From:	NEBRASKA PUBLIC POWER DISTRICT
To:
Shared Package
ML20153E951	List: ML20153E953 NLS8800109, Application for Amend to License DPR-46,revising Tech Specs Re Standby Liquid Control Sys.Evaluation of Changes Per 10CFR50.92 Requirements Encl.Fee Paid
References
NUDOCS 8805100185
Download: ML20153E953 (3)

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qa LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS 3.4 STANDBY LIQUID CONTROL SYSTEM 4.4 STANDBY LIQUID CONTROL SYSTEM Applicability: Applicability:

Applies to the operating status of Applies to the surveillance require-the Standby Liquid Control System, ments of the Standby Liquid Control System.

Objective: Objective:

To assure the availability of a sys- To verify the operability of the tem with the capability to shutdown Standby Liquid Control System.

the reactor and maintain the shutdown condition without the use of control rods.

Specification: Specification:

A. Normal System Availability A. Normal System Availability During periods when fuel is in the The operability of the Standby Liquid reactor and prior to startup from a Control Systeu shall be shown by the Cold Condition, the Standby Liquid Performance of the following tests:

Control System shall be operable, except as specified in 3.4.B below. 1. At least once per month each pump This system need not be operable loop shall be tested for operability when the reactor is in the Cold by recirculating demineralized water Condition and all control rods are to the test tank, fully inserted and Specification 3.3.A is met. 2. At least once during each operating cycles

a. Check that the settings of the system relief valves are 1450 < P < 1680 psig and the valves will reset at P > 1300 psig,

b. Manually initiate che system, except explosive valves, and pump boron solution from the Standby Liquid Contret Storage Tank through the recirculation path. Minimum pump l '

flow rate of 38.2 gpm against a system head of 1300 psig shall be l verified. Af ter pumping boron solution the system will be flushed with demineralized water.

c. Manually initiate one of the Standby Liquid Control System Pumps and i

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- v 3.4 BASES (cont'd.) .

The volume versus concentration requirement of the solution is such that, should evaporation occur from any point within the curve, a low level alarm will annunciate before the temperature versus concentration requirements are exceeded.

The quantity of stored boron includes an additional margin (25 percent) beyond the amount needed to shutdown the reactor to allow for possible imperfect mixing of the chemical solution in the reactor water.

A minimum quantity of 2840 gallons of solution having a 16.0 percent sodium pentaborate concentration, or the equivalent as shown in Figure 3.4.1, is required to meet this shutdown requirement.

The NRC's final rule on Anticipated Transients Without Scram (ATWS),

10CFR50.62, requires that the Standby Liquid Control System (SLCS) be modified to provide a minimum flow capacity and boron content equivalent in control capacity to 86 gpm of 13 weight percent sodium pentaborate solution for a 251 inch I.D. vessel. For Cooper Nuclear Station, with a 218 inch I.D.

vessel, the equivalent minimum flow rate is 66 gpm at 13 weight percent sodium pentaborate. This equivalence is met with both SLCS pu=ps supplying their minimum flow rate of 38.2 gpm with a solution concentration of at least 11.5 weight percent of sodium pentaborate. Because ATWS is a very low probability event and is considered to be beyond the design basis for CNS, the surveillance and limiting condition for operation requirements need not be more stringent than the original SLCS design basis requirements. The SLCS changes made as a result of the ATWS rule do not invalidate the original system design basis.

4.4 BASES STANDBY LIQUID CONTROL SYSTEM Experience with pump operability indicates that the monthly test, in combination with the tests during each operating cycle, is sufficient to maintain purp pe rf o r=anc e . The only practical time to fully test the liquid control system is during a refueling outage. Various components of the system are individually tested periodically, thus making unnecessary more frequent testing of the entire system.

The bases for the surveillance requirements are given in subsection III.9.6 of the Final Safety Analysis Report, and the details of the various tests are discussed in subsection III.9.5. The solution temperature and volume are checked at a frequency to assure a high reliability of operation of the system should it ever be required.

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NEBRA5KA Pu8 tic PowtR OlSTRICT COOPER NUCLEAR STAfl0N i Sodium Pentaborate Solution Volume Concentration Requirements FIGURE 3.4.1 112

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