ML20205E418

Forwards Nonproprietary & Proprietary Responses to NRC 870210 Request for Addl Info Re Util 861223 Request for Amends to Licenses NPF-37 & NPF-66,removing Resistence Temp Detector Bypass Manifolds in RCS

ML20205E418
Person / Time
Site:	Byron, Braidwood, 05000000
Issue date:	03/20/1987
From:	Ainger K COMMONWEALTH EDISON CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
Shared Package
ML19292H011	List: ML20205E418 ML20205G159
References
2743K, NUDOCS 8703300611
Download: ML20205E418 (6)

Text

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!_\ls One First Nabonel Plaza. Chee00, Imnois Address Reply to: Post Omco Box 767 CNce00. Imnois 80000 0767 March 20, 1987 Mr. Harold R. Denton, Director Office'of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington,'DC 20555

Subject:

Byron Station Units 1 and 2 Application for Amendment to Facility Operating Licenses NPF-37 and NPP-66, Appendix A Technical Specifications NRC Docket Nos. 50-454 and 50-455 References (a): December 23, 1986 letter from K.A.~ Ainger to H.R. Denton (b): February 10, 1987 letter from L.N. Olshan \

to D.L. Farrar

Dear Mr. Denton:

I Reference (a) transmitted our request for a license amendment l regarding removal of the resistance temperature detector (RTD) bypass manifolds in the reactor coolant system. Reference (b) contained a request for additional information regarding the subject amendment. Attachment A of this letter lists the NRC questions presented in reference (b). Attachment B of this letter contains the responses to the questions in Attachment A.

Westinghouse has refined the portions of the statistical setpoint study which are affacted by this modification based on a more detailed evaluation of Byron specific values of temperature, pressure and flow measurement uncertainties. This has resulted in minor changes to the revised Technical Specification values and some values listed in the licensing report, both of which were transmitted with reference (a). Attachment C of this letter contains the revisions to the Technical Specification values and Attachment D contains the revisions to the licensing report (WCAP-11323).

In addition, the revisions to the Technical Specifications transmitted in reference (a) have been modified to allow operation of Unit 1

.or Unit 2 with or without the RTD bypass manifolds removed. This will avoid the need for issuance of a license amendment at the time the modification is installed on each unit.

The revisions to the Technical Specification values have been reviewed and approved by both On-site and Off-site review in accordance with Commonwealth Edison Company procedures. Our determination of no significant hazards considerations presented in reference (a) is not affected by these minor changes contained in Attachments C and D.

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Mr. H. R. Denton March 20, 1987 Since some of the information contained in Attachments B and D is proprietary to Westinghouse Electric Corporation, it is suppported by an affidavit signed by Westinghouse, the owner of the information. The affidavit sets forth the basis on which the information may be withheld from public disclosure by the Commission and addresses with specificity the considerations listed in paragraph (b)(4) of Section 2.790 of the Commission's regulations.

Attachment E contains a Westinghouse Application for Withholding (CAW-87-004),

accompanying Affidavit, and Proprietary Information Notice.

Accordingly, it is respectfully requested that the information which is proprietary to Westinghouse be withheld from public disclosure in accordance with 10 CPR 2.790 of the Commission's regulations. . Correspondence with respect to the proprietary aspects of the Application for Withholding or the supporting Westinghouse Affidavit should reference CAW-87-004 and should be addressed to R.A. Wiesemann, Manager Regulatory and Legislative Affairs, Westinghouse Electric Corporation, P.O. Box 355, Pittsburgh, PA 15230.

Based on a detailed evaluation of the final design drawings, we have determined that installation of this modification will take longer than previously anticipated. It is estimated that an additional two weeks will be required to complete this installation on Byron Unit 1. This would extend the present Unit I refueling outage and delay startup of Unit 1. Consequently, installation of this modification on Unit I has been postponed to a subsequent refueling outage. Our current plans are to install this modification on Unit 2 during its first refueling outage.

Very truly yours,

[

i K. A. Ainger l Nuclear Licensing Administrator la l

Attachments (A): NRC Questions contained in Reference (b)

(B): Responses to NRC Questions (C): Revisions to Technical Specification Values (D): Revisions to WCAP-11323 (E): Westinghouse Application for withholding cc: Byron Resident Inspector L. N. Olshan - NRR Region III Office - RIII 2743K

8 O ATTACHMENT A RE00EST FOR ADDITIONAL INFORMATION REGARDING PTD BYPASS MANIFOLD REMOVAL

1. Provide a discussion on the setpoint methodology and error allowances used to establish the revised technical specification allowable values for the Overpower AT, Overtemperature AT and Low Reactor Coolant Flow reactor trios and for the Low-low Tavg (P-12) 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 Commonwealth 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 FCAP. 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 cuoted 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 lea will recuire manual action to defeat the failed signal ard that a manual rescalino will be made of the electronics to average the remainina sinnals 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 in this process.

6. In Table ?.1-1 of WCAP-11324, Response Time Parameters for RCS Temperature Measurement, the PTD 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 setecints (see Question No. 151 Is there a possibility that the values in Table 2.1-1 will need modification after observing the startup results?

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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. ,

10. You state on page 13 of WCAP-11324 that with the use of three T RTDs (resultingfromtheeliminationoftheRTDbypasslines)theRC$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 Question 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 nf 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 determined 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 operationrequired(seeQuestionNo.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 taken?

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 both the plant process computer and the special test equipment or a DVM at the input to the racks.

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 4.2 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 Table 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 pro.iect for each unit. This should include the following:

(a) doses and manpower for major subtasks; (b) typical dose rates expected; and (cl 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 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.

20. Identify the t be generatede.g., (ypes andcomponents, piping, volumes ofinsulation),

radioactiveandwaste which discuss are expected t disposal plans for these wastes.

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).

ATTACHNDrf E WESTINGHOUSE APPLICATION FOR WITHHOLDING i

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