ML20211E011

Forwards Request for Addl Info Re NRC Review of Util Info on Plant Protective Sys Trip Setpoints & Surveillance Requirements Against Draft Safety Evaluation Forwarded on 860124

ML20211E011
Person / Time
Site:	Fort Saint Vrain
Issue date:	10/16/1986
From:	Heitner K Office of Nuclear Reactor Regulation
To:	Robert Williams PUBLIC SERVICE CO. OF COLORADO
References
TAC-47416, NUDOCS 8610220334
Download: ML20211E011 (12)

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o UNITED STATES P o NUCLEAR REGULATORY COMMISSION

! y WASHINGTON, D. C. 20555

/ October 16, 1986 Docket No. 50-267 Mr. R. O. Williams, Jr.

Vice President, Nuclear Operations Public Service Company of Colorado Post Office Box 840 Denver, Colorado 80201-0840

SUBJECT:

REQUEST FOR ADDITIONAL'INFORMATION FOR PLANT PROTECTIVE SYSTEM TRIP SETPOINTS AND SURVEILLANCE REQUIREMENTS FOR FORT ST. VRAIN NUCLEAR GENERATING STATION Ref: (a) R. F. Walker letter to H. N. Berkow, Technical Specification Change Request To The Plant Protective System Trip Setpoints, May 15, 1986, Public Service Company of Colorado.

(b) 0. R. Lee letter to E. H. Johnson, Proposed Changes to Sections 2.1, .

3.3, 4.0, 5.0, LCO 4.4.1, and SR 5.4.1 of The Fort St. Vrain Technical Specifications, P-85214, June 21, 1985, Public Service Company of Colorado.

(c) H. N. Berkow letter to R. F. Walker, Fort St. Vrain - Plant Protection System Trip Setpoints, January 24, 1986, U. S. Nuclear Regulatory Commission.

We have reviewed the information you resubmitted with your letter dated May 15, 1986, Ref.(a), on Plant Protective System Trip Setpoints for the Fort St. Vrain Technical Specifications. Your previous submittal, Ref.(b), had combined Plant Protective System Trip Setpoints for the Fort St. Vrain Technical Specifications that accounted for instrumentation uncertainties as well as other upgrade considerations.

In Ref.(c), a draft Safety Evaluation was forwarded with a request for you to resubmit only the trip setpoint uncertainty material from your earlier submittal. The current request for additional information is a result of our review of your current submittal, against our draft.

Please provide the required information within 30 days of receipt of this letter. If you feel that further discussion would be helpful in resolving these open issues, please call me at (301) 492-8288.

4 8610220334 DR 861016 p ADOCK 05000267 PD_R

October 16, 1986 Mr. R. O. Williams, Jr. The information requested in this letter affects fewer than 10 respondents; therefore, OMB clearance is not required under P.L.96-511.

Sincerely, original sig.ned by Kenneth L. Heitner, Project Manager Standardization and Special Projects Directorate-Division of PWR Licensing-B Office of Nuclear Reactor Regulation

Enclosure:

As stated cc w/ enclosure:

See next page DISTRIBUTION:

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Mr. R. O. Williams, Jr. -

2-The information requested in this letter affects fewer than 10 respondents; therefore, OMB clearance is not required under P.L.96-511.

Sincerely, Kenneth L. Heitner, Project Manager Standardization and Special Projects Directorate Division of PWR Licensing-B Office of Nuclear Reactor Regulation

Enclosure:

As stated , .

cc w/ enclosure:

See next page 1

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Mr. R. O. Williams Public Service Company of Colorado Fort St. Vrain cc:

Mr. D. W. Warembourg, Manager Albert J. Hazle, Director Nuclear Engineering Division Radiation Control Division Public Service Company Department of Health of Colorado 4210 East lith Avenue P. O. Box 840 Denver, Colorado 80220 Denver, Colorado 80201 Mr. David Alberstein, 14/159A Mr. J. W. Gahm, Manager GA Technologies, Inc. Nuclear Production Division Post Office Box 85608 Public Service Company of Colorado San Diego, California 92138 16805 Weld County Road 19-1/2 Platteville, Colorado 80651 Mr. H. L. Brey, Manager Nuclear Licensing and Fuel Division Mr. L. W. Singleton, Manager Public Service Company of Colorado Quality Assurance Division P. O. Box 840 , . Public Service Company of Colorado Denver, Colorado 80201 #

16805 Weld County Road 19-1/2 Platteville, Colorado 80651 Senior Resident Inspector U.S. Nuclear Regulatory Commission Mr. R. F. Walker P. 0. Box 840 Public Service Company of Colorado Platteville, Colorado 80651 Post Office Box 840 Denver, Colorado 92138 Kelley, Stansfield & 0'Donnell Public Service Company Building Commitment Control Program Room 900 Coordinator 550 15th Street Public Service Company of Colorado Denver, Colorado 80202 2420 W. 26th Ave. Suite 100-D Denver, Colorado 80211 Regional Administrator, Region IV-U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 '

l. Arlington, Texas 76011 Chairman, Board of County Commissioners of Weld County, Colorado Greeley, Colorado 80631 Regional Representative Radiation Programs Environmental Protection Agency 1 Denver Place 999 18th Street, Suite 1300 Denver, Colorado 80202-2413

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ENCLOSURE ADDITIONAL INFORMATION NEEDED TO COMPLETE REVIEN OF PLANT PROTECTIVE SYSTEM TRIP SETPOINTS AND SURVEILLANCE REQUIREMENTS FOR FORT ST. VRAIN NUCLEAR SENERATING STATION

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r The following is a list of requests for additional information needed to complete this review. '

1.

Provide a more rigorous notation, such as h(Normal-64.6 psi).

Presently, P.3.3-2a, Table 3.3-1, Ites 1.c, the equal-to-cr-less-than-sign on 64.6 psi can be interpreted to mean more than 64.6 psi below normal or less than 64.6 psi below normal.'

2.

Provide the correct value for power runback in the FSAR for a circulator trip. The discussion ca Circulator Speed-Low, P.43 of Attachment 4 to P-85214 (PSC June 21, 1985, Letter), states that the circulator trip initiates a power runback to 50%. FSAR Section 7.1.2.6 indicates a power runback to 65% on a circulator trip.

3.

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Provide consistent values for steam ingress in the FSAR in Section 14.5. PSC's discussion of the Primary Coolant Pressure-High Scraa setpoint relates comparison to existing FSAR Analyses in Section 14.5.

i However, the following discrepancies exist in the FSAR.

FSAR SECTION 14.5 fair. Table 14.5-3 Steam Innress Value Ficure-Steam Inoress Value 2 14,580 lb -20,000 lb (Figure 14.5-2) 4 2,160 lb 1,400 lb (Figure 14.5-4) 6 0,000 lb l 7,000 lb (Figure 14.5-6) .

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4.

Provide additional information to justify deletion of Wide Range Channel Rate of Change-High, which was transmitted in the PSC June 21, 1985, letter, P.4.4-3c, Table 4.4-1 (Part 2), and included in the NRC sarkup letter of January 24, 1986. Although it is not in the specification section, this scram function is discussed in the basis on P.4.4-10a. This scram function is also listed in the FSAR scras function Table 7.1-2.

5.

Provide additional information to justify deletion of Primary Coolant Moisture High Level Monitor and Loop Monitor, which were transmitted in the PSC June 21, 1985, letter, P.4.4-4b, Table 4.4-2 (Part 1), and included in the NRC markup letter of January 24, 1986. These loop shutdown functions are also listed in the FSAR Loop Shutdown Function Table 7.1-3.

6.

Provide additional information to justify why the High Differential Temperature between Loop 1 and Loop 2 Loop Shutdown Function is not in the FSAR. Also, include in the Technical Specification basis a discussion of this loop shutdown function. Item 7c, P.4.4,-4b, Table 4.4-2 (Part 1), is the Loop Shutdown Trip function High Differential Temperature between Loop 1 j and Loop 2 which also appears in the existing Fort St. Vrain Technical l Specifications (FSV TS) on P.4.4-5. Although this loop shutdown function is I

in the specification section, it is not discussed in the basis (P6s 4.4-11, 11a and lib) of this loop shutdown function. Also, this loop shutdcun function does not appear in the FSAR loop shutdown Table 7.1-3.

6 7.

Provide acditional information to justify deletion of reference to figures 4.4-la'and 4.4-1b, P.4.4-5a, Table 4.4-3 (Part 1), ites 1. These were previously included in the PSC letter of June 21, 1985, and were included in the NRC markup of the January 24, 1986, letter. Figures 4.4-la and 4.4-1b for the Circulator Speed-Low should be retained.

8.

Provide additional information to justify deleting the Programmed Feedwater Flow-Low, P.4.4.-5a, Table 4.4-3 (Part 1). Specifications for Programmed Feedwater Flow-Low f o,r Loop 1 and 2 f or both circulators, and f or one circulator, were included in PSC's letter of June 21, 1985, and the NRC

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markup of letter dated January 24, 1986, but they have been deleted without explanation in the resubmittal. Although they are not discussed in the specification section, a discussion of these circulator trip functions can be found in the basis on P.4.4-12. These circulator trip functions are also in the FSAR circulator trip function Table 7.1-4. In their May 15, 1986, letter, PSC states that additional analyses were agreed to in past consitaents to analyze these trips using the ISA S67.04 sethodology and that they would be forthcoming. The existing trip setpoints were to be included for the interia. NRC letter dated January 24, 1986, in the marked up -

tables, reccamended incorporating of the existing Prograssed Feedwater

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Flow-Low. Also, the NRC letter of January 24, 1986, did request additional analyses for the Fixed Feedwater Flow-Low setpoint, but PSC did not provide, or sention, these latter analyses in their letter.

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9.

Provide additional information to justify why the specif5' cations for RWP functions were deleted, P.4.4-6a, Table 4.4-4 (Part 1). The rod withdrawal prohibit (RWP) function for Startup Channel Rate of Change-High for Channels 1 and 2 and Wide Range Channel Rate of Change-High for j Channels 3, 4, and 5 have been deleted without explanation. Although no l specifications exist for these trips, they have been included in the basis I

section on Page 4.4-13. These RWP functions were previously submitted by i

PSC in their June 21, 1985, letter and were included in the NRC sarkup in the NRC letter of January 24, 1986. These functions are also listed in FSAR

Section 7.1.2.2, Rod Withdrawal Prohibit Inputs.

10.

1 Provide additional information to justify why the RWP functions were i deleted, P.4.4-6a, Table 4.4-4 (Part 1). The rod withdrawal prohibit functions for Linear Channel-High Power RWP for Channels 3, 4, and 5 and Channels 6, 7, and 8 were deleted without explanation. Although no specifications exist for these trips, they have been included in the basis section on Page 4.4-13. Also, these functions had previously been transmitted by PSC's June 21, 1985, letter and these functions and the associated Figure 4.4-2 were included in the NRC aarkup in the January 24, 1986, letter. These functions are also listed in FSAR Section 7.1.2.2, Rod Withdrawal Prohibit Inputs.

11.

f Provide additional information to clarify why itees 3a and 3b functional unit descriptions were changed from " Linear Channel-30% RWP" to

" Linear Channel-High Power RWP," P.4.4-6a, Table 4.4-4 (Part 1), although the trip setpoints of 1,30% are unchanged. The deleted functions (see 10 above) functional unit descriptions had been " Linear Channel-High Power RWP' and were applicable up to 1001 power per the deleted Figure 4.4-2. This change confuses the distinction between the two types of channels.

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Provide additional information to clarify deletion of RWP Function Multiple Rod Pair Withdrawal, P.4.4-6a, Table 4.4-4 (Part 1). Although included in the PSC June 21, 1985, letter, this function was deleted from the PSC May 15, 1986, letter. Although the NRC markup in the January 24, 1986, letter did not list this function, it should have.

13.

Provide additional information to clarify why, at least, the (30% of rated power RWP setpoint does not require instrument uncertainty to be taken into account, P.4.4-6a, Table 4.4-4 (Part 1). Also, re-evaluate the other RWPs to ensure that if they were deleted, an operator single failure in positioning the interlock sequence switch would not bypass required reactor protection trip functions. P.6, Attachment 3 to the PSC letter of June 21, 1985, stated that the rod withdrawal prohibits were not analyzed as part of the program to comply with the guidance of the ISA Standard 567.04, because no credit is taken for then in accident analyses. Without the rod withdrawal prchibit, high power operation (130%) could be consented with the interlock sequence switch (ISS) in the low power position with four scram functions and two circulator trip functions bypassed (FSAR ,

Section 7.1.2.0). As this is an operator single failure defeat of part of the reactor protection system at high power, the 30% of rated power RWP appears to be a required safety function to prevent this occurrence.

Therefore, at least this function of the RWP should have had instrument uncertainty taken into account for the setpoint. Otherwise, additional safety analyses are required to demonstrate safe operation with the above reactor protection system functions bypassed.

14.

Provide additional information to clarify for each circulator trip I

function how the associated equipment, if any, is protected if the trip is

! effectively bypassed per Iten c. P.4.4-2. (Ites c), which has been added, l

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) would allow continued circulator operation even though the circulator trip instrumentation may be inoperable and may not be placed in the tripped condition (see note f) (P.4.4-8). If trip conditions were present but the trip was bypassed because of (Item c), then continued operation of the circulator eight endanger the equipment which the trip is meant to protect.

For example, the basis (P.4.4-12) for Circulator Speed-Low trip is to protect against flooding in the steam generator superheater section.

Placing the Two-Loop-Trouble input on the affected circulator in the tripped condition per Ites c, does not protect against flooding of the steam generator superheater section.

15.

3 Provide additional information to justify deletion of the asterisk footnote on Circulator Speid-High Water, P.4.4-5c.

16.

Provide additional information to clarif f deletion of reference to notes (a) and (n) in Table 4.4-4 on rod withdrawal prohibit inputs, P.4.4-8. Although the NRC sarkup in the letter dated January 24, 1986, indicated deletion of (a) and (n) in Table 4.4-4, (a) and (n) clarify the inputs (5%, 30% or high power) to associate with the notes on P. 4.4-8.

Also, if the high power RWPs are reinstated (see Iten 10 above), the association to be made in Table 4.4-1 will be even less clear. Response to this consent should consider Consent 20 on consistent format for location of footnotes in Enclosure 4(a) to the NRC letter, dated January 24, 1986.

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Provide additional information as to why many of the Allowable Values and Trip Setpoints in Table 3.3-1 and Tables 4.4-1, 4.4-2, 4.4-3, and 4.4-4 are the same, P.3.3-5. The basis on P.3.3-5 states that for these parameters; "The portion of the instrument channel which is tested aanthly is checked only for logic operability; hence, no monthly drift is determined." The basis also states that:"The test selected for drift considerations was the monthly functional test, as opposed to the annual calibration test." However, ISA S67.04 specifically states (P.ll, 4.3.3) that:'the trip setpoint shall be a value which allows margin f or drif t and adjustaent," and further clarifies drift as:" Drift of that pcrtion of the instrument channel which is tested when the setpoint is determined."

Monthly functional checks which test only for logic operability do not, therefore, qualify as the'1e'tss for which setpoints are determined. PSC, by using the sonthly functional tests in rtich setpoints are not determined, has eliminated the cistinction between Allowable Value and Trip Setpoint intended by ISA S67.04. PSC states that they take drift into consideration in the allowances between the Analysis Value and the Allowable value.

Although drift is thus accountad for, this approach does not segregate the instrument uncertainties per the intent of ISA S67.04. This choice of using the sonthly functional tests was apparently specified by the NRC at the October 27, 1983, seeting. (See P. 5, Attachment 3, Ref 1). The intent of the ISA S67.04 Standard in segregating the drift allowance and setpoint tolerance allowance between the trip setpoint and the allowable value was to emphasize those uncertainties, inaccuracies, etc., that change. Lack cf accounting for drift has been the subject of many LERs. Also, drift is the one inaccuracy that is subject to the most change and was segregated by the ISA Coseittee (Ref 6).

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) REFERENCES

1. O. R. Lee letter to E. H. Johnson, " Proposed Changes to Sections 2.1, 3.3, 4.0, 5.0, LCD 4.4.1, and SR 5.4.1 of the Fort St. Vrain Technical Specifications," June 21, 1985, Public Service Company of Colorado.

2. R. F. Walker letter to H. N. Berkow, " Technical Specification Change Request to the Plant Protective System Trip Setpoints," May 15, 1986, Public Service Company of Colorado.

3. ISA-S67.04, "Setpoints for Nuclear Safety-Related Instrumentation used in Nuclear Power Plants," 1982, Instrument Society of America.

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, 4. D. Wareebourg letter,to.J. T. Collins, " Fort St. Vrain Plant Protective Systes Technical Specifications," March 9, 1984, Public Service Company

of Colorado.

5. H. N. Berkow letter to R. F. Walker, " Fort St. Vrain-Plant Protection Systee Trip Setpoints," January 24, 1986, U.S. Nuclear Regulatory Commission.

6. Telephone consunication, on July 28. 1986. J. C.'Stachew. E6&B Idaho, with E. C. Wenringer, U.S. Nuclear Regulatory Consission ISA-S67.04 Committee Member.

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