ML20210R277
| ML20210R277 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 02/10/1987 |
| From: | Olshan L Office of Nuclear Reactor Regulation |
| To: | Farrar D COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 8702170368 | |
| Download: ML20210R277 (5) | |
Text
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February.10, 1987 Docket Nos. STN 50-454 DISTRIBUTION STN 50-455 J5EEEENT NRC PDR
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Mr. D. L. Farrar T. Novak OGC Director of Nuclear. Licensing E. Jordan B. Grimes Comonwealth Edison Company J. Partlow N. Thompson Post Office Box 767 L. Olshan C. Vogan Chicago, Illinois 60690 ACRS(10)
Dear Mr. Farrar:
SUBJECT:
REMOVAL OF RTD BYPASS MANIFOLD - REQUEST FOR ADDITIONAL INFORMATION By letter dated December 23,.1986, you requested an amendment to the Byron Technical Specifications to accomodate removal of the resistance temperature detectors (RTD) bypass manifold system.
Enclosed is a request for additional information that we need to complete our review.
In order to complete our review by February 28, 1987, we need this information by February 13, 1987.
The reporting and/or recordkeeping requirements of this letter affect fcwer than ten respondents; therefore, OMB clearance is not required under PL 96-511.
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Leona d N. Olshan, Project Manager Projact Directorate #3 Division of PWR Licensing-A
Enclosure:
As stated cc: See next page Cvogan@
V,GPDf3 PD#3 U LOlshan:pds 2/s0/87 2/N/87 w
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18' Mr. Dennis L..Farrar.
Byron Station Commonwealth Edison' Company Units I and 2 cc:
Mr. William Kortier Ms. Diane Chavez Atomic Power Distribution 528 Gregory Street Westinghouse Electric Corporation Rockford, Illinois 61108 Post Office Box 355 Pittsburgh, Pennsylvania 15230 Regional Administrator, Region III U. S. Nuclear Regulatory Commission Michael Miller 799 Roosevelt Road Isham, Lincoln & Beale Glen Ellyn, Illinois 60137 One First National Plaza 42nd Floor Joseph Gallo, Esq.
Chicago, Illinois 60603 Isham, Lincoln & Beale Suite 1100 Mrs.-Phillip B. Johnson 1150 Connecticut Avenue, N.W.
1907 Stratford Lane Washington, D. C.
20036 Rockford, Illinois 61107 Douglass Cassel, Esq.
Dr. Bruce von Zellen 109 N. Dearborn Street Department of Biological Sciences Suite 1300 Northern Illinois University Chicago, Illinois 60602 DeKalb, Illinois 61107 Ms. Pat Morrison Mr. Edward R. Crass 5568 Thunderidae Drive Nuclear Safeguards & Licensino Rockford, Illinois 61107 Sargent & Lundy Engineers 55 East Monroe Street Ms. Lorraine Creek Chicago, Illinois 60603 Rt. 1, Box 182 Manteno, Illinois 60950 Mr. Julian Hinds U. S. Nuclear Regulatory Commission Byron / Resident Inspectors Offices 4448 German Church Road Byron, Illinois 61010 Mr. Michael C. Parker, Chief Division of Engineering Illinois Department of Nuclear Safety 1035 Outer Park Drive Springfield, Illinois 62704 l
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1
I FNCLOSURE D
RE00EST FOR ADDITIONAL INFORMATION REGARDING PTD RYPASS MANIFOLD REF0 VAL 1.
Provide a discussion on the setpoint methodolooy and error allowances used to establish the revised technical specification allowable values for thP Overpower AT, Overtemperature AT and Low Reactor Coolant Flow reactor trips and for the Low-low Tavg (P-1?) interlock resulting from the RTD bypass manifold removal.
2.
Provide a discussion of the equipment environmental qualification as related to compliance with 10 CFR 50.49, 3.
A bias for a failed T hot signal is discussed on page 2 of Attachment C to Comonwealth Edison's letter dated December 23, 1986. Provide a discussion on how a bias value is determined and how this value is manually entered into the system.
4.
The last sentence in the second paragraph on page 26 of WCAP-11323 states:
"Non-safety related control signals continue to be derived from protection channels." This statement seems to be in error since the current RTD installation has RTD's dedicated to control system usage. Please explain.
5.
Section 5.0 of WCAP-11323 discusses control system inputs of Tavg.
Development of this signal is not covered in the text or in Figure 1.3-1 of the VCAP.
Please discuss where (in the control or protection system) and how the three hot leg RTD signals are summed and Tavg is computed.
6.
A change in flow measurement uncertainty is shown in the Tech Spec basis on page B 3/4 2-4.
However, corresponding changes in the main body of the Tech Spec are not presented. Usually the flow measurement uncertainty value is quoted initially in the main body of the Tech Spec and any change also affects a change in the minimum RCS flow value in gpm.
7.
For RTD failures you state on page 5 of WCAP-11324 that there is a spare RTD available in the cold leg. However, you state that a failure of an RTD in the hot leg will require manual action to defeat the failed signal and that a manual rescalina will be made of the electronics to average the remaining signals shown in Figure 1.3-1.
What is the time interval to defeat the failed signal? What is the time interval to rescale the electronics to average the remaining signals? Describe the steps involved l
in this process.
8.
In Table ?.1-1 of WCAP-11324, Response Time Parameters for RCS Temperature Measurement, the RTD filter time constant (sec) is shown to be zero.
In Section 5.0 of WCAP-11324 (page 54) there is reference to Table 2.1-1 and a statement indicating that there may be a need to modify control system setooints (see Question No. 15).
Is there a possibility that the values in Table 2.1-1 will need modification after observing the startup results?
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u 9.
You state on page 13 of WCAP-11324 that with the latest Westinghouse RTD cross-calibration procedure (resulting in lower RTD calibration uncertainties at the beginning of a fuel cycle) it is 'possible to reduce the RCS flow measurement uncertainty. Please describe what this method is, how it differs with the previous method, and the amount of reduction in flow measurement uncertainty achieved by using this new RTD cross-calibration method.
RTDs You state on page 13 of WCAP-11324 that with the use of three T 10.
(resulting from the elimination of the RTD bypass lines) the RC$0 flow uncertainty value is reduced. Please provide a comparison of the improved accuracy of the new RTDs with the old RTDs and the improvement in flow measurement due this change.
In Section 4.2 of WCAP-11324 it is stated that RTD error is increased (see Ouestion No. 14). Please explain these statements that seems to be opposed to each other.
- 11. You state on page 14 of WCAP-11324 that the overall temperature streaming uncertainty applied to the calorimetric flow measurement is only slightly larger than the uncertainty used in the previous analyses.
Please provide the values for comparison and indicate the amount that this change of value has on the flow measurement uncertainty.
17.
In the last paragraph on page 15 of WCAP-11324 it is stated that test data has been collected to provide a plus or minus value for a bias to be applied if one of the three RTDs is out of service. How is the bias value detennined for a particular out-of-service RTD since the temperature value of each RTD (120' apart) may differ depending on its circumferential position? You state that this provision for operating with only two hot leg RTDs in service in done through the electronic system.
Is a manual operation required (see Question No. 7)? When will the failed RTD be replaced? Is there a written rule for this in the FSAR or Tech Specs?
If two of the three RTDs should fail, what steps would be taktn?
- 13. The results of the flow measurement uncertainty analysis are presented in Tables 3.1-1 to 3.1-4 on pages 16 to 19 of WCAP-11324 and are currently being reviewed.
In a previous analysis for another plant, it was not possible to verify the results because some of the information had plus or minus values for which the minus values were not identified. Do any of the values presented have missing signs that need to be accounted for?
If so, provide the information needed. Also, Table 3.1-1 lacks information on the values for parameters (SCA, MATE, SPE, STE etc.) that are used for obtainino the channel allowance, CSA.
Please supply these values and the formulas for combining the parameters to obtain the CSA value for b,th the plant process computer and the special test equipment or a D?M at the input to the racks, i,
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- 14. You state on page 21 of WCAP-11324 that the results of system uncertainty verify that sufficient allowance exists in the reactor protection system setpoints to account for the increased RTD error for the new RdF RTDs. Because of this, you state the current values of the nominal setpoints noted above (Section 4.F of WCAP-11324), as defined by the Byron Technical Specifications, remain valid. Please provide the results of the uncertainty calculations and show how they verify that there is sufficient allowance in the reactor protection setpoints to account for the increased RTD temperature error. Show what the RTD error is now and what it was before.
- 15. You state on page 54 of WCAP-11324 that "The need to modify control system setpoints will be determined during plant startup following installation of the new RTD system by observing control system behavior" and you also refer to Teble 2.1-1 which gives RTD system time response parameters.
Is there a possibility that the values in Table 2.1-1 will need modification after observing the startup results?
- 16. Describe the actual hardware changes and activities that will be made to accomplish the proposed modifications.
Include those construction steps which result in occupational exposure to personnel or generate radioactive waste.
Identify differences, if any, in these changes and activities for the two Byron units.
- 17. Provide an estimate of the occupational radiation dose determined for the overall modification project for each unit. This should include the following:
(a) doses and manpower for maior subtasks; (b) typical dose rates expected; and (c) maximum dose rates expected, and locations.
- 18. Provide a comparison of occupational dose estimated for task performance and expected dose reduction (e.g., reduced leakage and maintenance, ISI requirements reduced, reduced numbers of shutdowns, reduced general area dose rates, fewer " hot spots" and crud traps) over plant life as a result of these modifications.
19.
Identify measures to be taken to assure that doses to workers during task performance will be ALARA. This should cover, for example, task I
planning, special training, use of mockups, area and system decontamination and airborne radioactivity, efforts to minimize number of workers, and application of experience from similar efforts in the industry.
be cenerated (ypes and volumes of radioactive waste which are expected to Identify the t 20.
e.g., piping, components, insulation), and discuss disposal plans for these wastes.
l 21.
Identify and briefly discuss any special radiological problems which may be associated with this task (e.g., very high dose rates, very high contamination levels, high radioindine levels, need for multiple dosimetry, brief stay times).
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