View source for B12605, Proposed Tech Specs,Modifying Calibr Requirements for Power Range Nuclear Instrumentation When Plant Operated at steady- State Reduced Power & Channels Adjusted to Provide Enhanced Overpower Protection

{{Adams
| number = ML20236R486
| issue date = 11/19/1987
| title = Proposed Tech Specs,Modifying Calibr Requirements for Power Range Nuclear Instrumentation When Plant Operated at steady- State Reduced Power & Channels Adjusted to Provide Enhanced Overpower Protection
| author name = 
| author affiliation = CONNECTICUT YANKEE ATOMIC POWER CO.
| addressee name = 
| addressee affiliation = 
| docket = 05000213
| license number = 
| contact person = 
| document report number = B12605, NUDOCS 8711230310
| package number = ML20236R481
| document type = TECHNICAL SPECIFICATIONS, TECHNICAL SPECIFICATIONS &amp; TEST REPORTS
| page count = 3
}}

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F Docket No. 50-213 B12605 Attachment I l
                                                                                                  .1 Haddam Neck Plant Proposed Revision to Technical Specifications                                   l 1
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:1 8711230310 871119 PDR P    ADOCK 05000213                                                                           l PDR November 1987 1

4.2    OPERATIONAL SAFETY ITEMS-Applicability:   Applies to items directly related to safety limits and limiting conditions for operation.
Objective:       A. Instrumentation shall be checked, tested, and calibrated at sufficiently frequent intervals to assure safe operation.
B. Equipment and sampling tests shall be conducted at sufficiently frequent intervals to assure safe operation.             ]
1 Specification:    Calibration testing, and checking shall be performed as detailed            1 in Tables 4.2-1 and 4.2-2                                                    j l
Basis:            Nuclear flux channels shall be calibrated every day when the plant is at power using a heat balance calculation to account for discrepancies resulting from changes in the control rod pattern              j and core physics parameters. This heat balance calibration is                 l not required when the nuclear flux channels have been adjusted               i to maintain a 9% margin to the overpower trip setpoint during                l reduced power steady state operation. This practice insures that operation at intermediate power levels will be bounded by the analyzed accident scenarios which are terminated by the                      i overpower trip.
Process system channels for parameters such as pressure, flow, level, and temperature may be subject to small long-time drif t errors. Available statistics based on Yankee-Rowe nuclear plant experience have shown that the drif t of trip set points between refuelings is not excessive and has generally. averaged less than 2% with a maximum 3.5          < Control channel total channel drif t has averaged less than L 3% with a maximum drif t of 4.5%
Between refuelings, a regular check by the operators of similar instruments in separate channels will point up any inconsistent channel in time to test and repair that channel's components before they jeopardize plant operations.
l Operator checks will also reveal blown fuses, opened circuits or improperly functioning electronic components.           In general, conditions such as these will be annunciated at the main control board and therefore can be immediately noted for testing.
Periodic testing of instrumentation channels when no deficiency is apparent is not considered desirable. The risk of inadvertently tripping the plant is inc: eased whenever a channel is being tested. The risk that a channel will be lef t inoperative af ter a l                           test, while small, is nevertheless also increased. Furthermore, I
while the channel is on test, it is not available to perform its design function, be it control or protection. _ Experience with process instrumentation in industry, thermal plants and at the Yankee-Rowe power reactor supports these statements.

==Reference:==
(1)    FSAR - Section 7 4-2

l Table 4.2-1                                               ~
I Minimum Frequencies for Testing, Calibrating and/or                                 '
Checking Instrument Channels Channels                   Action     <           ' Minimum Frequency
                                                                                                         )
: 1. Nuclear Power          Calibrate with heat      Daily /except when plant is shut             q balance calculation
* down.                                   l    3 Check test trip          Each shif t twice a month.
function.                                                           .
: 2. Intermediate Range Test log level and           Prior to each startup if not                 I start up rate circuits   done in previous week.                       1 Check                    Each shif t when in service.
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: 3. Source Range           Test                     Prior to startup if not per-                 i formed within preceding week.
                                                                                                         ]
Check                    Each shif t when in service.                   j
: 4. Reactor Coolant        Calibrate                Each refueling.                               ;
Temperature            Check                    Each shif t.
                                                                                                          .I
: 5. Reactor Coolant        Calibrate                Each refueling                               f Flow                   Check                    Each shif t                                    !
Test                     Each scheduled shutdown if not                )
tested or calibrated in ' pre-               J ceding 6 months.
: 6. Pressurizer Level      Calibrate                Each refueling Check                    Each shif t                                    i Test                     Every 6 weeks                                  l
: 7. Pressurizer Pressure Calibrate                  Each refueling                                 ;
Check                    Each shif t                                    !
Test                     Every 6 weeks Except when the power range nuclear instruments are adjusted to be within 9%
of an overpower trip setpoint. This exception applies only during reduced power steady state operation. When this exception is used, a heat balance calculation will continue to be performed on a daily basis to determine core power, and the power range channels will be verified daily to be 996 below the selected overpower trip setpoint.
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