U-601848, Requests Change to Tech Spec Bases to Replace Maplhrg Limit Factor 0.85 for Single Recirculation Loop Operation W/ Ref to Core Operating Limits Rept & Correcting Number of Nozzles in RHR Containment Spray Train a

Requests Change to Tech Spec Bases to Replace Maplhrg Limit Factor 0.85 for Single Recirculation Loop Operation W/ Ref to Core Operating Limits Rept & Correcting Number of Nozzles in RHR Containment Spray Train a

ML20079C730
Person / Time
Site:	Clinton
Issue date:	06/17/1991
From:	Spangenberg F ILLINOIS POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20079C731	List: ML20079C735 U-601848, Requests Change to Tech Spec Bases to Replace Maplhrg Limit Factor 0.85 for Single Recirculation Loop Operation W/ Ref to Core Operating Limits Rept & Correcting Number of Nozzles in RHR Containment Spray Train a
References
U-601848, NUDOCS 9106250240
Download: ML20079C730 (3)

Text

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U.001868

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ILLill0IS POWER Wi?M CLIN 10N l'O%TH STATION, l' O box 67t.. CLINTON, ILLINOIS 61727w7ti. TI:LI:l':lONI: (217) 93 NMI June 17, 1991 10CFR50.36 Docket No. 50 461 Document Control Desk Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

Clinton Power Station Technical Specification Bases

Dear Sir:

The purpose of this letter is to request changes to Illinois Power Company's Clinton Power Station (CPS) Technical Specification Bases. The Bases contained in the CPS Technical Specifications summarize the reasons for the Specifications in Sections 2.0, 3.0 and 4.0, but in accordance with 10CTR50.36, are not part of the Technical Specifications. Therefore, these Bases changes are not being submitted as an application for amendment of Operating License NPF 62 since the requirements of 10CPR$0.90 are not applicable to such changes.

The purpose or nature of these changes is as follows: 1) to replace the Maximum Average Planar Linear Heat Generation Rate (MAPlJlGR) limit f ae. tor "O.85" for single recirculation loop operation with a reference to the CORE OPERATING LIMITS REPORT since this factor is operating cycle specific, 2) to correct the number of nozzles in the Residual lleat Removal (RHR) containment spray Train A" to reflect the deletion of two spray nozzles, and 3) to clarify the Bases for the Main Control Room and Standby Cas Treatment system filter train heaters to note that heater test results are corrected for actual bus voltage during testing.

A discussion of each of these changes and revised (marked-up) Bases pages are provided in Attachment 1.

Sincerely yours, V. N ,.v p %m F. A. Sp ngenH rg, III Manager,\Licek ing and afety DAS/alh Attachment cc: NRC Clinton Licensing Project Manager NRC Resident Office NRC Region III, Regional Administrator Illinois Department of Nuclear Safety 9106250240 910617 PDR ADOCK 05000461 fl f

P PDR

1 Attachment 1 to U 601848 Page 1 of 6 As identified in the cover letter, the proposed Technical Specification Bases changes consist of three separate changes based on their nature and purpose. Each of the three changes in described below.

1. Replace Sinrle Loop Operation MAPUICR Multiplier witiLL}le f e renc e t o lhe CORE OPERATING LIMITS REPORT During two recirculation loop operation, the Maximun) Average Planar Linear lleat Generation Rate (MAPulGR) limits specified in the CORE OPERATING LIMITS REPORT (COLR) are soultiplied by the smaller of the flow dependent MAPUICR (MAPFACg) factor or the power dependent MAPulGR (MAPFAC p ) factor corresponding to the existing core flow and power conditions. This assures adherence to fuel racchanical design bases during the roost limiting plant transients. The MAPTACr factors are established to protect the core from core flow runout transients.

The MAPTAC p factors are established to protect the core from plant transients other than core flow runout.

During single recirculation loop operation, the MAPulGR limits specified in the COLR are multiplied by the smallest of MAPFACr.

MAPFAC , or a factor which is derived from sine,le loop operation lossokcoolantaccident (LOCA) analyses. This single loop operation MAPulGR factor is required in order to account for earlier boiling transition at the limiting fuel node during single loop operation as compared to standard 1DCA evaluations.

By Amendment No. 28 to the CPS Technical Specifications, the cycle-specific parameters in the CPS Technical Specifications were replaced with a reference to the C0lR in accordance with NRC Ceneric Letter 88 16. llowever, at that time, it was not recognized that the single loop operation MAPulGR factor is cycle specific, although it is included in the COLR. Consequently, the single loop operation MAPulGR factor (where it appears in the Technical Specification Bases) was not replaced with a reference to the COLR. (For the current CPS operating cycle, the single loop operation MAPUlGR factor is included in item b on page 4 of the COLR for Reload 2, Cycle 3, Revision 0).

This Bases change merely replaces the value of the single loop operation MAPulGR factor specified on Bases page B3/4 2 2 with a reference to the COLR similar to the reference provided in Technical Specification 3/4.2.1. The value of this factor will continue to be determined for each operating cycle as required by Technical Specification 6.9.1.9. As a result, this proposed change cannot increuse the probability or the consequences of any accident previously evaluated, create the possibility of a new or different accident, or result in a reduction in the margin of safety,

2. Correct the Number of Containment Spray Nozzles The containment spray mode of the Residual Heat Removal (RHR) system is provided to protect the containment from overpressurization in the event of excessive suppression pool bypass leakage following a postulated 1DCA. The RHR containment spray system consists of two 100% capacity trains, each with two spray rings located at different elevations on the inside ci .:umference of the containment. RHR pump A supplies one train and R4R pump B supplies the other train.

• Attachment I l to tb601848 page 7 of 6 l

condensatioa of water vapor in the cont.ainment is enhanced by the u s. e of nozzles on the spray rings. The turbulence enused by the spray system also aids in mixing the containment air volume to maintain a homogeneous ml>.ture for hydrogen control.

The original design for the containment spray systems included "

nozzles per train. During initial plant construction in April 1985, two of the nozzles were not installed in containment spray Train "A" because of interference with ventilation ductwork. lloweve r , the deletion of these two nozzles was not reflected in the cps Updated Safety Analysis Report (USAR) or Technical Specification Bases.

Therefore, this Bases change is provided to reflect that there are 249 nozzles in containment spray Train "A" and 251 nozzles in containment spray Train "B" Lyalunt.lon of deletion of these two nozzles f rom containment spiny Train "A" demonstrated that at least 90% of the net free area continues to be capable of being sprayed and that there is a negli gible impact on the effective containment spray dispersion area.

As a result, this proposed change cannot increase the probability or the consequences of any accident previously evaluated, create the possibility of a new or different kind of accident, or result in a reduction in the margin of safety.

3. fla ri f y Tes t inc of Fi l t tLhain llealen by Amendment No. $$ to the cps Technical Specifications, the values for the heat required to be dissipated from the Standby Cas Treatment system (SGTS) and the Main Cont rol Room (MCR) filter train heaters as provided in Technical Specification Surveillance Requirements 4.6.6.3.d.5 and 4.7.2.e.6 were revised, prior to issuance of Amendment No. 55, these values were specified as "20.0 4/- 2.0 LW" for the SGTS and "16 4/- 1.6 kW" for the MCR. Subsequent to issuance of Amendment No. 55, these values are specified as "at 1 cast 18.0 kW" and "at least 14,4 kW" As stated in the NRC Safety Evaluntton Report (SEH) for Amendment No.

55, the basis for the change was to allow for heater testing at the cps bus voltages which are higher than the volt age used to establish the heater's rating. Testing at higher bus voltages could cause the measured heater output to exceed the specified 10% tolerance As stated in the SER, the nominal tating for each heater is based on the manufacturer's rating with an assumed bus voltage of 460 volts. The nominal bus voltage at cps is 480 volts.

The changes to Bases pages B3/4 6 8 and B3/4 7-1 are provided to clarify that the heat dissipation rates specified in these surveillance requirements are based on a bus voltage of 460 volts and that the test results must be adjusted to account for actual hun voltage during the t est. This will ensure that heaters tested at higher bus voltages have not degraded below the acceptable level which was based on a bus voltage of 460 volts. As a result, these proposed changes cannot increate the probability or the consequences of any accident previously evaluated, create the possibility of a new or different kind of accident, or result in a reduction in the margin of safety.

,