ML20235A997

Forwards Response to NRC 861016 Request for Addl Info on Util 850621 & 860515 Requests for Amend to Tech Specs Re Trip Setpoints & Operating Requirements.Proposed Tech Specs Also Encl

ML20235A997
Person / Time
Site:	Fort Saint Vrain
Issue date:	08/28/1987
From:	Robert Williams PUBLIC SERVICE CO. OF COLORADO
To:	Calvo J NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM), Office of Nuclear Reactor Regulation
Shared Package
ML20235B002	List: ML20235A997 ML20235B009
References
P-87278, TAC-47416, NUDOCS 8709230490
Download: ML20235A997 (40)

Text

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A.smus t 28, 1987 $.n6*fcEso201 os40 Fo'rt St. Vrain Unit No. 1 R.O. WILLIAMS, JR.

ENT P-87278 QPES U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Attention: Mr. Jose A. Calvo Director, Project Directorate IV Docket No. 50-267

SUBJECT:

Technical Specification Change Request to the Plant Protective System Trip Setpoints

REFERENCE:

See Enclosure 1

Dear Mr. Calvo:

Public Service Company of Colorado (PSC) submitted by letters dated June 21, 1985 (Reference 1) and May 15, 1986 (Reference 2), an amendment request to the Fort St. Vrain (FSV) Technical Specifications on the Plant Protective System (PPS) Trip Setpoints and operating requirements. The latter amendment request was based on NRC written direction submitted in Reference 3 and verbal communication with the NRC staff.

In a letter dated October 16, 1986 (Reference 4), the NRC staff submitted a request for additional information on the revised amendment request of May 15, 1986. The issues in the above letter were also discussed in a telecommunication conference with the NRC staff on July 30, 1986.

In addition to the above request, the NRC staff, in a letter dated November 26, 1986 (Reference 5), recommended that PSC resubmit the proposed Technical Specification with the PPS Trip Setpoint Allowable Values based on the refueling surveillance rather than the monthly surveillance. It should be noted that this revision in the methodology does not change the Trip Setpoint values previously analyzed and submitted with the exception as noted below.

PSC is submitting our responses to these requests in the following Attachments:

Attachment 1: PSC Response to the Request for Additional Information

\

8709230490 870828 '

1 kOO i PDR ADOCK 05000267 ,

P PDR (

P-87278-Page 2 August 28, 1987 Attachment 2: Proposed Amendment Request to the FSV PPS Technical Specification During the recalculation process for ' Primary Coolant Pressure High/ Low and Circulator Drain Malfunction, an error was found in the original loop's instrumentation accuracy and/or assumptions used to establish the Trip Setpoint. The corrected Trip Setpoints are shown in Attachment 2. In addition, several editorial changes (commas, hyphens, consistency in titles, capitalization, etc.) have been made L

in the revised amendment which are not being specified in the

" Summary of Proposed Changes." All c'1ange:, relative to the current approved Fort St. Vrain Technical Specifications are identified in the "Sunrnary of Proposed Changes" and by margin markings. This License Amendment Request supercedes that submitted on May 15, 1986 (Reference 2).

As discussed with the NRC staff in a telecommunication conference on July 15, 1987, PSC will be submitting, under a separate cover letter, additional information and supporting analyses for the PPS parameters Fixed Feedwater Flow Low and Circulator Speed Programmed with Feedwater Flow. As recommended by the NRC staff in Reference 3, the Trip Setpoint/ Allowable Value for the Fixed Feedwater Flow-Low parameter is being retained at the present trip setting value presently specified in the Technical Specifications. Although the two values are listed the same, the actual Trip Setpoint is conservatively set to account for some inaccuracy / drift.

The License Amendment Fee of $150.00 was submitted in the original Amendment Request dated June 21, 1985 (Reference 1). The significant hazards consideration submitted in the same previous request is still considered valid for the changes noted in this new submittal, with the exception of the methodology discussion. The revised methodology is defined in the basis section of this request.

A 90 day period after approval of these revisions by the Commission is requested before the revised sections are incorporated into the FSV Technical Specifications. The 90 day period is required by PSC to revise the applicable procedures, computer software, Plant Protective System daily log sheets, and the Technical Specification Compliance Log. This time is also required to retrain all licensed personnel.

P-87278-Page 3 .

3

~ August 28, 1987.

Should you have any questions concerning this matter, please contact

.Mr. M. H. Holmes at (303) 480-6960.

Very truly yours, ifh AN r

R. O. Williams, Jr.

Vice President, Nuclear Operations R0W/JS:jw Attachments.

cc: Albert J. Hazle-Colorado Department of Health Regional Administrator, Region IV Attention: Mr. J.E. Gagliardo, Chief Reactor Projects Branch Mr. R.E. Farrell Senior Resident Inspector Fort St. Vrain l

P-87278 Page 3 August 28, 1987 Should you have any questions concerning this matter, please contact Mr. M. H. Holmes at (303) 480-6960.

Very truly yours, h[ Cdw R. O. Williams, Jr.

Vice President.

l Nuclear Operations R0W/JS:Jw Attachments cc: Albert J. Hazie Colorado Department of Health l Regional Administrator, Region IV Attention: Mr. J.E. Gagliardo, Chief Reactor Projects 8 ranch Mr. R.E. Farrell Senior Resident Inspector Fort St. Vrain l

Reviewed By: O

,e j h

l

.)..

. P-87278 Page 4 August 28, 1987 Enclosure 1

1) PSC Letter Lee to Johnson,

' dated June 21, 1935 (P-85214).

2)- PSC Letter Walker to Berkow, dated May 15,.1986 (P-86279)

3) NRC Letter Berkow to Walker, dated January 24, 1986 (G-86053)-

4) NRC Letter Heitner to Williams, dated October 16,1986(G-86545)

5) NRC Letter Heitner to Williams, dated November 26,1986(G-86624) 4

BEFORE.THE UNITED STATES NUCLEAR REGULATORY COMMISSION In the Matter. of the Facility Operating License of )

PUBLIC SERVICE COMPANY OF COLORADO-l

[

Application for Amendment to Appendix A of Facility Operating License License No. DPR-34 0F THE PUBLIC SERVICE COMPANY OF COLORADO FOR THE

-FORT ST. VRAIN NUCLEAR GENERATING STATION This application for Amendment to Appendix A of  ;

Facility Operating License, License No. DPR-34, is submitted for NRC review and approval.

Respectfully submitted, PUBLIC SERVICE COMPANY OF COLORADO By R. O. Williams, Jr., Vice President, Nuclear Operations KELLY, STANSFIELD & 0'DONNELL Bryant O'Donnell James K. Tarpey Public Service Company Building l Denver, Colorado 80202 l Attorneys for Applicant j i

.4 L________________ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . __

j

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION

'In the Matter Public. Service Company of Colorado ) Docket No. 50-267 Fort St. Vrain Unit No. 1 )

AFFIDAVIT R. O. Williams, Jr., being first duly sworn, deposes and says:

That he is Vice President of Nuclear Operations of Public Service Company of C0lorado, the Licensee herein; that he has read the foregoing Application of Amendment to Appendix A of Facility Operating License and knows the contents thereof, and that the statements and matters set forth therein are true and correct to the best of his knowledge, information, and belief, effd R'. O. Williams, Jr//

Vice President, Nuclear Operations STATE OF haded COUNTY OF Mm,w v' )

Subscribed and sworn to fb fore me, a Notary Public on this 4f@ day of (famet$ , 1987.

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My connissien expires duAtub 72 ,198g. /4#**

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,n ATTACHMENT 1 TO P-87278

' PSC RESPONSE TO THE REQUEST FOR ADDITIONAL INFORMATION

Attachment 1 to P-87273 Page 2 NRC REQUEST 1:

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

Presently, P.3.3-2a, Table 3.3-1, Item 1.c, tfie equal-to-or-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.

PSC RESPONSE 1:

The use of the " equal-to-or-less-than" sign ( indicates that thetripsetpointand/orallowablevalueisobta$)dby ine ' backing off', from the normal, by the value indicated. This notation is consistent with.the existing Technical Specifications and the Westinghouse Standard Technical Specifications. An example in the STS is as follows:

" Automatic Switchover to Containment Sump"

• RWST level-low, > (

_ ") from tank base Containment sump level-high, < ( ") above elevation

( ') -

Since the use of this' notation has been implemented in the  ;

training program and will continue to be, PSC proposes not to '

change the current practice.

1 I

l L___-__-_---- __

.()

Attachment I to P-87278 Page-3 6

- NRC REQUEST 2:

Provide the correct value .for power runback in the FSAR for a

_ circulator trip. The discussion on 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.

PSC RESPONSE 2:

A review of the FSAR has determined that FSAR section 7.1.2.6 is in error for the runback value. The FSAR in the Revision 5 update has been corrected tc reflect a power runback to "50%"

upon a circulator trip.

[

Attachment 1 to P-87278 Page.4-NRC REQUEST 3:

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

FSAR SECTION 14.5 Case Table 14.5-3 Steam Ingress Value Figure-Steam Ingress Value 2 14,580 lb 20,000 lb (Figure 14.5-2) i 4 2,160 lb 1,400 lb (Figure 14.5-4) 6 8,080 lb 7,000 lb (Figure 14.5-6)

PSC RESPONSE 3:

The curves of " Steam in Primary Coolant System" or " Steam Content" are the difference between the amount of vaporized H20 inleakage up to any moment in time, less the amount of steam-consumed by reaction with graphite up to the same moment in time.

The consumption of steam by graphite reaction is most apparent in Figure 14.5-4, where the " steam content" curve can be clearly J seen to decrease with time.

If the H20 inleakage and the reaction with graphite were completed within the cutoff time of the curve (generally 1800 seconds), then the difference between the columns (in the table)

" Total H2O Inleakage (lb)" and " Total H20 Reacted (lb)" should equal the curve " Steam in Primary Coolant System (lb)" at the cutoff time of the curve. This is approximately the result for cases 4 and -6 from Table 14.5-3 compared to Figures 14.5-4 and 14.5-6. Allowance should be made for graphic artists' tolerance in transcribing data to curves. Other possible causes of minor apparent discrepancies are that in some cases the steam-graphite reaction may not be completed at the time of cut-off at the right side of the figures, and/or the drainage of water from the steam generator into the PCRV may not have been completed at that time.

With regard to Case 2, we find that the Updated FSAR inadvutently presents an outdated set of curves in Figure 14.5-l 2.

I t - - _-

i

! Attachment 1 to P-87278 Page 5 The last FSAR revision to Case 2 (Figure 14.5-2, the table, and the descriptive text) was made in December 1974, replacing the 1973 Amendment 26 of the original FSAR. Subsequently, in 1982 the entire FSAR was updated and reprinted as the "FSAR UPDATE".

During the editorial process of the FSAR UPDATE, the out-of-date Figure 14.5-2 from Amendment 26 was inadvertently substituted for the correct and later figure of December 1974 (The text description of Case 2 and Table 14.5-3 remained up-to-date).

Attached for information are copies of Figure 14.5-2 from Amendment 26 and from the 12/74 revision. Figure 14.5-2 has been corrected in Revision 5 of the FSAR update.

d FSAR UPDATE Revision 1 Attachment 1 E to P-87278 Page 6 h

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l-Attachment I to P-87278 Page 12 NRC REQUEST 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 markup 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 scram function Table 7.1-2.

PSC RESPONSE 4:

As discussed with the NRC staff in'the July 30, 1986 te'lecon, this parameter, along with several others, was not included in the revised submittal for the following reasons:

The original Technical Specification submittal of June P1, 1985 (P-85214), contained various new PPS parameters which were not included in the existing Technical Specifications.

This submittal provided both proposed operating and surveillance requirements. The NRC's response and draft safety evaluation in a letter dated January 24, 1986, only addressed the operating requirements.

In a followup telecon, the NRC staff provided PSC with the direction that the revised amendment request should only include those parameters which now exist in the present Technical Specifications. In addition, those new parameters would not have had approved surveillance requirements had we included them.

The discussion in the Technical Specification basis has been deleted as reflected in Attachment 2 of this letter.

i l

l Attachment 1 to P-87278 Page 13

)

l NRC REQUEST 5:

Provide ' additional information to justify deletion of Primary l Coolant Moisture High Level Monitor and Loop Monitor, which were I 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.

PSC RESPONSE 5:

See PSC Response 4.

Attachment 1 to P-87278 Page 14 NR' REQUEST 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 and Loop 2 which also appears in the existing Fort St. Vrain Technical Specifications (FSV TS) on P.4.4-5. Although this loop shutdown function is in the specification section, it is not discussed in the basis (PGs 4.4-11, lla and lib) of this loop shutdown function. Also, this loop shutdown function does not appear in the FSAR loop shutdown Table 7.1-3.

PSC RESPONSE 6:

a) Although the FSAR does not explicitly address the parameter as "High Differential Temperature Between Loop 1 and Loop 2", it does discuss the existence of a comparator circuit between the two loops and an interlock in FSAR section 7.1.2.4 under the loop shutdown inputs, b) The basis on page 4.4-12 and in the analysis value justification provided in Attachment 4 ir: the original Technical Specification submittal of June 21, 1985 (P-85214), does discuss the function of this parameter. ]

The basis on page 4.4-11b of Attachment 2 to this letter also discusses the function of this parameter.

c) Low superheat header temperature is identified as " sensed variable" No. 5 in Table 7.1-3 of the FSAR. As indicated there are three (3) thermocouple per loop.

Note (d) specifies that a trip will only occur if a coincident difference in temperature between loops is present.

Since the low temperature switches and the high differential temperature switches are different instrument circuits, PSC selected to specify these as separate parameters in the l proposed Technical Specifications Amendment Request. PSC j understands that upon approval of the resubmitted proposed 4 amendment, that the FSAR will require updating to reflect l the approved PPS setpoint.  !

1 i

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Attachment 1

- to P-87278 l Page 15 l:

[ NRC REQUEST 7: .i Provide additional information to justify deletion of reference to figures 4.4-la and 4.4-1b, P.4.4-Sa, -Table 4.4-3 (Part 1),

item 1. These were previously included in the PSC letter of June

, 21, 1985, and were included in.the NRC markup of the January 24, letter.

1986, Figures. 4.4-la and 4.4-1b for the Circulator Speed-Low should be retained.

. PSC RESPONSE 7:

See PSC Response 4.

t

Attachment I-t to P-87278 Page'16 NRC REQUEST 8:

Provide additionai information'to justify deleting the Programmed Feedwater Flow-Low, P.4.4.-Sa, Table 4.4-3 (Part 1).

Specifications for Programmed Feedwater Flow-Low for Loop 1 and 2 for both circulators, and for one circulator, were included in PSC's letter of June 21, 1985, and the NRC 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 commitments to analyze these trips usin the ISA S67.04 methodology and'that.

they would be forthcoming. gThe existing Trip Setpoints were to be included for the interim. NRC letter dated January 24, 1986, in the marked up tables, recommended incorporating of the existing Programmed Feedwater 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 mention these latter analyses in their letter.

PSC RESPONSE 8:

See PSC Response 4.

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f!ttachment 1 to P-87278 Page 17 s

NRC REQUEST 9:

Provide additional information to justify why the specifications 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 c.

4 1

Rate of Change-High for Channels 1 and 2 and Wide Range Channel

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l Rate of Change-High for Channels 3, 4, and 5 have been deleted without explanation. Although no specifications exist for these ,-

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! trips, they have been included in the-basis section on Page 4.4- <

12. These RWP functions were previously submitted by PSC in l their June 21, 1985, letter and were included in the NRC markup. '

l in the NRC letter of January 24, 1986. These functions are also l_ listed in FSAR Section 7.1.2.2, Rod Withdrawal Prohibit Inputs.

PSC RESPONSE 9:

See PSC Response 4.

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s l ' NRC REQUEST 10:

Provide additional infomation to justify why the RWP functions were deleted, P.4.4-6a,* Table 4.4-4 (Part 1). The rod withdrawal

' prohibit functions for_Lisiear3 Channel-High Power RWP for Channels 3, 4, and 5 and .Channe @ 6,b.7, and 8 were deleted without explanation. Althoughi no 4 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

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.,. June 21,1985, . letter and these functions and the associated O Miigure 4.4-2 were included in the NRC markup in the January 24,

'ga e 1986,. letter. These functions are also listed in FSAR Section 7.1.2.2, Rod Withdrawal Prohibit Inputs.

". PSC RESPONSE 10:

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See PSC Response.41 L

Attachment 1 to P-87278 Page 19 NRC REQUEST 11:

Provide additional information to items 3a and 3b functional unit descriptions were changed froaclarify why'Channel-Linear 30% RWP" to " Linear Channel-High Power RWP," P.4.4-6a, Table 4.4-4 (Part 1), although the Trip Setpoints of <30% are unchanged.

The deleted functions'.(see 10 above) functioiial unit descriptions had been " Linear Channel-High Power RWP" and were applicable up to 100% power per the deleted Figure 4.4-2. This change confuses the distinction between the two types of channels.

PSC RESPONSE 11:

The ~ functional unit description titles submitted in the original amendment request of June 21, 1985 reflected more accurately its association.with the protective function (e.g., 5%, 30%).

The titles 'were changed back in the May 15, 1986 submittal, as reflected in Attachment 2 of this letter, to be consistent with those present in the existing Technical Specifications and their associated surveillance.

Attachment 1 to P-87278 Page 20 NRC REQUEST 12:

Provide additional information to clarify deletion of RWP -

Function Multiple Rod Pair Withdrawal, P.4.4-6a, Table 4.4-4 l (Part 1). Although included in the PSC June 21, 1985, letter, 1 this function was deleted from the PSC May 15, 1986, letter. ]

Although the NRC markup in the January 24, 1986, letter did not i list this function, it should have.

PSC RESPONSE 12:

See PSC Response 4.

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Attachment I to P-87278 Page 21'-

NRC REQUEST 13:

Provide additional information to clarify why, at least, the <30% j of rated power RWP setpoint does not require. instruiEent '

uncertainty to be taken into account, P.4.4-6a, Table 4.4-4 (Part l 1). Also, re-evaluate the other RWPs to ensure that if they were deleted, an operator single failure in positioning the interlock I sequence switch would not bypass required reactor protection trip I functions. P.6, Attachment 3 to the PSC letter of June 21, 1985, stated that the rod withdrawal prohibits were not analyzed as j

part of. the program .to comply with the guidance of the ISA i Standard 567.04, because no credit is taken for them in accident analyses. Without the rod withdrawal prohibit, high power operation (>30%) could be commenced with the interlock sequence switch (IST) in the low power position with four scram functions and. two circulator trip functions bypassed (FSAR Section )

7.1.2.8). As this is an 0;;erator 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.

PSC RESPONSE 13:

The ISS, as explained in FSAR Section 7.1.2.8, is an administratively controlled method for operating protection system bypasses during rise to power. In this regard it is similar to the BWR Reactor Mode Switch (NUREG 0123 Rev. 3). The 30% RWP is included as a second line ofdefense(oradded reminder) to the reactor operator to place the ISS in the correct position prior to exceeding 30% ieactor power. FSAR Table 7.1-6 '

is an analysis of improper ISS settings arm the effect on rise to power.

The underlying rationale for not applying instrumentation uncertainties to the RWP circuitry is that of avoiding the potential for initiating protective actions when system i conditions do not warrant it. To apply uncertainties to these parameters, especially the 30% RWP, would mean backing off from this value, thus resulting in a setpoint somewhat less than 30%.  ;

By doing so, certain plant protective functions would be '

" enabled" prior to s temperatures, etc.) being ystemwithin operating normal parameters operating (pressures, conditions. flows,

Attachment l' to P-87278 Page 22

' Operating Procedure OPOP III. and Surveillance Procedures 5.4.1.1.4.C-D/5.4.1.4.2.C-D and 5.4.1.1.5.C-M/5.4.1.4.3.C-M

. require that the linear and wide range nuclear instrument channels, which input signals proportionate to reactor- power -to the RWP circuitry, be calibrated against a secondary heat balance prior to reaching 30% power (in the range of 26 to 28% power).

This assures that the 30% RWP operates with an accuracy close to that of the secondary heat balance, and will in fact actuate close to 30% reactor power if the operator continues to withdraw control rods in an attempt to increase power above 30% without placing the Interlock Sequence Switch (ISS) in the Power

, position.

Moving the ISS from the - Low Power to Power position arms the following' Plant Protective System trips:

• Primary Coolant Pressure, Low-Scram Hot Reheat Header Pressure, Low-Scram Main Steam Pressure. Low-Scram Low Superheat Header Temperature (Loop 1 or Loop 2) - Loop Shutdown Circulator Speed High/ Low (programmed by Feedwater Flow) -

Circulator Trip Fixed Feedwater Flow Low (Loop 1 or Loop 2) - Circulator Trip Due to the installation of the Steam Line Rupture Detection / Isolation System (SLRDIS) and incorporation of SLRDIS into the FSV Technical Specifications, the Hot Reheat Pressure -  :

Low and Main Steam Pressure - Low scram parameters are no longer relied upon to automatically shut down the reactor in the event of a High Energy Line Break (HELB) since the SLRDIS actuation results in reactor scram for significant HELBs. These parameters will nevertheless have limiting conditions for operation in the FSV Technical Specifications and their associated instrumentation will continue to be surveilled per Technical Specification requirements as they provide defense-in-depth. SLRDIS is required to be operational whenever reactor power is above 2%.

If the operator fails to comply with Administrative Procedures, and withdraws rods such that reactor power exceeds 30% without placing the ISS in the Power position, the above automatic

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to P-87278 Page 23 protective actions would be inhibited. Due to the accuracy of the secondary calorimetric and the RWP circuitry, reactor power would not exceed about 34% without actuating the RWP. If the operator were to neglect placing the ISS in Power and exceed 30%

power, it is highly unlikely that an accident would occur in this circumstance, due to the short time spent in the'30% to 34% power

. range before the RWP would be received during the rise-to-power.

The probability of a required plant protective system response to mitigate an accident in the 30-34% range is very.small. Accident consequences for power range accidents are analyzed at conservative upper power limits. The consequences of accidents occurring from lower power levels have not generally been analyzed. The overall risk of a power range accident from low power levels (30% - 34%) is small given the short time at that power level as well as the less severe consequences expected from such power levels. Opera tor training and reliance on Administrative Controls via approved procedures to enable the protective functions listed above provides high confidence for safe reliable operations.

PSC has considered the impact of applying instrumentation uncertainties to the 30% RWP setpoint, and reducing the setpoint based on these inaccuracies. Application of these instrument uncertainties would result in a setpoint of approximately 26%.

This would preclude exceeding 26% reactor power until the ISS is placed in the Power position. Moving the ISS from the Low Power to the Power position at about 26% reactor power significantly increases the potential for unnecessary Plant Protective System trips. This is due to the fact that at 26% reactor power primary coolant pressure may be below its programmed scram Trip Setpoint and superheat header temperature may be below its Trip Setpoint.

Furthermore, the turbine-generator is brought on-line with the external electrical grid at approximately 28% reactor power, and this action needs to be accomplished with stability without being encumbered with a rod-withdraw prohibit setting in the same range. Reducing the RWP setting would also intrude into the 26%

to 28% range where secondary heat balances are made (heat balances are less accurate if performed at lower power levels).

Backing off the 20% RWP to accommodate instrument inaccuracies is inappropriate and unwarranted.

-l Attachment 1 to P-87278 Page:24 NRC REQUEST 14:

Provide additional information to clarify for each circulator trip function how-the associated. equipment, if any, is protected if the trip is effectively bypassed per Item c. P.4.4-2.(Item c),which has been .added, 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 might 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 Item c, does not protect against flooding of the steam generator superheater section.

PSC RESPONSE 14:

A review of the conditions permitted by Item 'c' on page 4.4-2 and Note 'f' on pace 4.4-8 determined that Item 'c' would have allowed the bypassing of a protective trip. Item 'c' has thus been deleted from the Technical Specification amendment request as shown in Attachment 2 of this letter, j

to P-87278 Page 24 NRC REQUEST 14:

Provide additional .information to clarify for each circulator trip function how the associated equipment, if any, is protected if the trip is effectively bypassed per Item c. P.4.4-2. (Item c),which has been added, 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 might 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 Item c, does not protect against flooding of the steam generator superheater section.

PSC RESPONSE 14:

A review of the conditions permitted by Item 'c' on page 4.4-2 and Note 'f' on page 4.4-8 determined that Item 'c' would have allowed the bypassing of a protective trip. Item 'c' has thus been deleted from the Technical Specification amendment request as shown in Attachment 2 of this letter.

Attachment I to P-87278 i Page 25 NRC REQUEST 15:

Provide additional information to justify deletion of- the asterisk footnote on Circulator Speed-High Water, P.4.4-Sc.

PSC RESPONSE 15:

The ' asterisk note on page 4.4-6 of the existing Technical Specifications applies only to the parameter " Circulator Speed-High Water." The note did not apply until the plant was already down to one circulator per loop'as specified. Were this provision to be invoked, plant operation personnel determined.

that continued operation in that mode would not be acceptable and would have shutdown the' plant.

Removal of the asterisk note places this parameter on an equal status with respect to the other circulator trip parameters.

This provides more conservatism in actuality than would have been allcwed with the note. Therefore, the removal of this provision supported overall consistency in plant safety.

_mm.._.

Attachment I to P-87278 Page 26 NRC REQUEST 16:

Provide additional information to clarify deletion of- reference to notes (m) and (n) in Table 4.4-4 on rod withdrawal prohibit inputs, P.4.4-8. Although the NRC markup in the letter dated January 24, 1986, indicated deletion of (m) and (n) in Table 4.4-4, - (m) and (n) clarify the inputs (5%, 30% or high power) to associated with the notes on P.4.4-8. Also, if the high power RWPs are reinstated (see Item 10 above), the association to be made in Table 4.4-1 will be even less clear. Response to this comment should consider Comment 20 on consistent format for location of footnotes in Enclosure 4(a) to the NRC letter, dated January 24. 1986.

PSC RESPCNSE 16:

A review of the proposed Technical Specification amendments determined that notes (m) and (n) were referred to as notes (x) and (y) in the applicable mode column in the June 21, 1985 letter. These notes were unintentionally left out in the May 15,

-1986 resubmittal.

Notes (m) and (n) have been added as shown in Attachment 2 of this letter. These notes are referenced in the " Trip Setpoint" column since they reflect a resetting of the trip function.

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l Attachm2nt 1

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to P-87278

~Page 27 NRC REQUEST 17:

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 monthly is checked only for logic i operability; hence, no monthly drift is determined." The basis )

also states that: "The test selected for drift considerations I was the monthly functional test, as opposed to the annual j calibration test." However, ISA 567.04 specifically states (P.11, 4.3.3) that: "the trip setpoint shall be a value which l allows margin for drift and adjustment," and further clarifies 4 drift as: " Drift of-that portion 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 tests for which setpoints are determined. PSC, by using the. monthly functional tests in which setpoints are _not determined, has eliminated the distinction 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 accounted for, this approach does not segregate the instrument uncertainties per the intent of ISA S67.04 This choice of using the monthly functional tests was apparently specified by the NRC at the October 27, 1983, meeting. (See P.5, Attachment 3, Ref.

1). The intent of the-ISA 567.04 Standard in segregating the drift allowance and setpoint tolerance allowance between the trip setpoint and the allowable value was to emphasize those i uncertainties, inar, uracies, etc., that change. Lack of 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 Committee (Ref 6).

i PSC RESPONSE 17:

Attachment 3 of the June 21, 1985 original amendment request  !

provided an overview of the historical development of the FSV '

setpoint re-evaluation program and the methodolgy developed using ISA S67.04, 1982 and NRC guidance.

The methodology established the monthly surveillance as the base for detennining the margin between the Allowable Value and Trip i Setpoint. This margin is determined by the drift of the components tested.

1 I

Attachment 1 to P-87278 Page 28 In subsequent discussions with the NRC staff and as recommended in an NRC letter, dated November 26, 1986 (Ref. 5), PSC has revised the methodology to use the refueling interval surveillance as the basis for the Allowable Value. This change in methodology provides for a defined margin between the Trip Setpoint and Allowable Value as shown in Attachment 2 with the exception of the 5% and 30% RWPs. See PSC response to NRC Question 13 for discussion of- these Trip Setpoints.  !

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i ATTACHMENT 2 TO P-87278 PROPOSED AMENDMENT REQUEST TO THE FSV PPS TECHNICAL SPECIFICATION l

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I ENCLOSURE 1 0F ATTACHMENT 2 of P-87278

SUMMARY

OF PROPOSED CHANGES a

SUMMARY

OF PROPOSED CHANGES SECTION DESCRIPTION LSSS 3.3 1. Page 3.3-1. Definitions are added for Trip Setpoint and Allowable Value.

2. Pages 3.3-2a, 2b, 2c, 3a, and 3b replace old pages'3.3-2 and 3.3-3.

A Trip Setpoint and Allowable Value are now specified f;r each parameter and two curves are used with Table 3.3-1.

Basis for LSSS 3.3 1. Pages 3.3-4 through 3.3-9 replace old pages 3.3-4 through 3.3-8. The new basis discusses the methodology for determining Trip Setpoint and Allowable Value and then describes the basis for each limiting safety system parameter.

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LCO 4.4-1 1. Page 4.4-1. Definitions added for Trip Setpoint and Allowable Value.

Two paragraphs of old page moved to next page.

2. Page 4.4-2. The paragraph on Table 4.4-1 expanded to add new requirements. The paragraph on Table 4.4-3 expanded and page reformatted. I i

3. Tables 4.4-1 through 4.4-4. The '

tables were reformatted to provide for a Trip Setpoint and Allowable Value to replace the Trip Setting. I Each table was solit into Part 1 )

containing Trip ietpoint and '

Allowable Values t e each parameter and a~ Part 2 containing Minimum Operable Channels, Minimum Degree of Redundancy and Permissible Bypass Conditions. Part 2 follows Part 1 for each table.

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,. '4. Old pages 4.4-3 through 4.4-6 and I 4.4-7 replaced by pages 4.4-3a, 3b, j 3c, 4a, 4b, 4c, 4d, Sa, 5b, Sc, 7a, 1 7b. 1 i

5. New page 4.4-4d. Permissible i Bypass Conditions clarified for parameter 7c to reflect actual design.

6. Page 4.4-8. Notes for Tables 4.4-1 through 4.4-4. Note (a) deleted as j Table 4.4-1 line items 3a and 3b refer operator to Table 3.3-1.

Note -(d) deleted as the Trip Setpoint and Allowable Value in new tables provide specific criteria for the Plant Electrical S -

Loss parameter. Note (e)ystem updated to correctly describe the undervoltage system design. Note (h) in existing license split into two separate notes (hl) and (h2) to more correctly reflect applicable permissible bypass conditions for the different types of moisture monitors.

Basis for LC0 4.4-1 1. Pages 4.4-10 through 4.4-13 of existing license replaced by new pages 4.4-10, 10a, 10b, 10c, 11, lla, 12, 12a, 12b, 12c and 4.4-13.

The .new basis is more descriptive than th original basis, i

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ENCLOSURE 2

'0F ATTACHMENT 2 0F P-87278 i

PROPOSED CHANGES TO LSSS'3.3 AND LCO 4.4.1 0F THE FSV TECHNICAL SPECIFICATIONS i

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