ML20012C438

Application for Amend to License NPF-58,revising Tech Spec Table 3.3.2-2,Item 5e Re RCIC Equipment Room Differential Temp Isolation Actuation Instrumentation Trip Setpoint & Allowable Value

ML20012C438
Person / Time
Site:	Perry
Issue date:	03/16/1990
From:	Kaplan A CLEVELAND ELECTRIC ILLUMINATING CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20012C439	List: ML20012C438 ML20012C441
References
PY-CEI-NRR-114, NUDOCS 9003210290
Download: ML20012C438 (9)

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THE CLEVELAND ELECTRIC ILLUMINATING COMPANY P.O. BOX 97 5 PERRY. OHIO 44081 5 TELEPHONE (216) 250 3737 5 ADDRESS-10 CENTER ROAD FROM CLEVELAND: 479 1260 5 TELEX: 241599 ANSWERBACK: CEIPAYO Al Kaplan Serving The Best location in the Nation PERRY NUCLEAR POWER PLANT VICE PHLSMNT nuca m onoue March 16, 1990 PY-CEI/NRR-il44 L U.S. Nuclear Regulatory Commission Document Control Desk Washington, D. C. 20555 Perry Nuclear Power Plant Docket No. 50-440 Technical Specification Change Request-- RCIC Equipment l Room Differential Temperature Isolation Actuation Instrumentation Centlemen:

The Cleveland Electric Illuminating Company (CEI) hereby requests amendment of Facility Operating License NPF-58 for the Perry Nuclear Power Plant, Unit 1.

In accordance with the requirements of 10CFR50.91(b)(1), a copy of this request for amendment has been sent to the State of Ohio as indicated below.

i This letter requests revision of Technical Specification Table 3.3.2-2, Itemr Se, the RCIC Equipment Room Differential Temperature Isolation Actuation Instrumentation Trip Setpoint and Allowable Value.

The request is a-followup to the previously submitted and approved change to the RCIC Equipment Room Differential Temperature Trip Setpoint and Allowable Value, documented in Amendment 26 issued January 30, 1990. Because that Amendment is only valid until the Lake Erie water temperature reaches 55 degrees F, CEI has considered alternatives which would establish year-round' values for the Trip Setpoint/ Allowable Value. Since historically Lake Erie l has reached 55 degrees F in early May it is requested that this change request be approved on or before May 8. 1990. Attachment 1 includes the Summary, Safety Analysis,-Significant Hazards and Environwental Considerations.

Attachment 2 includes the proposed markup of the Technical Specifications. .{

1 This requested amendment will provide a significant improvement in RCIC j reliability when responding to transients, however, CEI requests that the NRC continue to consider issuance of the amendment request submitted on January i 19, 1990 to remove the isolation function of the delta-T instruments. If you have any questions, please feel free to call.

Very,truly y rs ff O

h.

Al Kaplan P  ;

Vice President  ;

Nuclear Group ,

AK:nje  !

Attachments i cc: T. Colburn P. Hiland USNRC Region III [ l J. Harris (State of Ohio) /[/- l

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. Attach::nt 1 PY-CEI/NRR-1144 L Page 1 of 8 >

Summary / History On January 19, 1990 CEI submitted an Emergency Technical Specification change ,

request (PY-CEI/NRR-1124L) to delete the isolation function of the RCIC Equipment Room differential temperature (delta-T) instrumentation. The original request was submitted because the RCIC system had isolated on January 7, 1990 due to a false differential temperature signal (no actual steam system break had occurred) when RCIC had been responding to deliver vater to the Reactor Vessel. As discussed in that letter CEI felt that deletion of the i

automatic trip function of the RCIC Equipment Room delta-T was acceptable and the preferred position, since retention of the trip function vould potentially have a negative effect on RCIC reliability, and since there appears to be a regulatory basis for removal of the isolation function provided the alarm function is retained. It also appeared that determining a valid Trip Setpoint and Allovable Value vould be difficult due to the vide variety of parameters which affect the RCIC Equipment Room Differential Temperature Instrumentation.

In order to process the change under the conditions which existed in January (i.e. RCIC inoperable due to the RCIC delta-T instrumentation requiring a reactor plant shutdown by February 1, 1990), the NRC staff issued Amendment 26 on January 31, 1990 providing a new trip setpoint and allovable value. This amendment is only effective as long as Lake Erie water temperatures remain less than 55 degrees F. Historically lake water temperatures reach this value in early to mid-Hay.

In the time period since submittal of the previous amendment request, CEI has performed analyses to determine if a year-round trip setpoint and allovable value was feasible, or whether multiple values vould need to be proposed. It was concluded that year round single values for the isolation setpoint and allovable value were feasible and contained certain advantages over the use of multiple seasonal setpoints. If a multiple setpoint approach was used the plant would be required to physically change the isolation setpoint on the instrumentation at least twice a year. In the spring when the Lake Erie water i temperature reached the crossover temperatures (55 F) the delta-T trip l

setpoint vould be revised to account for the higher Lake temperature, and in the fall when Lake Erie water temperature again reached the crossover temperature, the delta-T isolation setpoint would be revised to account for the lover Lake temperature. Since there are two delta-T instruments-(one for each trip system) this vould result in four trip setpoint changes being made each year to the instrumentation.

Therefore, the only reason why a multiple setpoint approach would be considered would be if it was necessary for these delta-T instruments to be isolating steam leakage at an upper bound of 25 gpm versus utilizing an upper bound isolation value between 30 to 35 gpm. As noted in our previous correspondence, the sensitivity of the delta-T instruments to various size leaks varies as the temperature of the cooling water entering the room cooler varies. For any given setpoint value, as the water temperature entering the room cooler gets colder, the size of the steam leak which vill isolate the RCIC system gets smaller. If an attempt is made to restrict the maximum leak size isolated by these delta-T instruments to 25 gpm at any time of the year (and therefore with any lake temperature between 32 F and 80 F), then multiple setpoints vould have to be used. This multiple setpoint approach would result in a much more important disadvantage than just the additional setpoint

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- Atttchment 1 PY-CEI/NRR-1144 L Page 2 of 8 changes it would require; it vould impact directly on RCIC system reliability / availability to respond to plant transients. The RCIC system availability vould be decreased during three significant portions of the year, first during the entire vinter at very cold lake water temperatures, and again  !

in the late spring and early fall when the lake temperatures are just above l the crossover temperature of 55 degrees F. This availability reduction would  ;

occur during these periods of time because leak rates of 5 gallons per minute (gpm) or less vould isolate the RCIC system. Leak rates of this size could result from a simple gasket leak rather than an actual' crack of concern, and I the proper course of action in response to this small leak is an alarm with subsequent operator investigation, rather than the indiscriminate isolation of' the RCIC system when it is injecting coolant to the reactor vessel.

To eliminate these disadvantages, CEI concluded that one trip setpoint and allovable value should be determined for use year-round. This vill provide a significant reduction in the threat-to RCIC reliability while the NRC is reviewing our January 19, 1990 request to delete this automatic isolation.

Analyses were performed in order to determine which trip setpoint/allovable '

value vould provide for sufficient margin during all anticipated ranges of lake temperature to prevent spurious RCIC isolations, yet would provide automatic isolation if a steam leak of any significance in the RCIC Equipment Room should occur. In order to accomplish this with one trip setpoint, the size of steam leaks isolated by the delta-T instrumentation vill vary as the lake water temperatures vary, from approximately 15 gpm when the lake temperature is cold to approximately 35 gpm when the lake temperature is at its varmest. This arrangment provides delta-T generated isolation signals for a range of leaks centered around a nominal 25 gpm leak size. This range of leakage remains completely bounded by the USAR Analysis of.the Main Steam Line Break (MSLB) outside containment discussed in the USAR Section 15.6.4. The differential temperature trip setpoint and allovable value determined by the analyses were 95.9 degrees F and 97.2 degrees F respectively. This is based on a safety limit value of 102 degrees F.

Safety Analysis As discussed above, analyses were performed to determine one trip setpoint which could be used throughout the range of expected Lake Erie vater temperatures, to provide automatic RCIC isolation if actual steam leaks of sufficient amount occur, but to prevent spurious RCIC isolation. First, a series of calculations were completed to determine the temperature rise in the RCIC Equipment Room following postulated steam leaks of various sizes. The calculations were performed using the personal computer version of.the COMPARE computer code.* Some of the key input parameters used by the code vere-room volumes, initial room temperatures / pressures, initial relative humidity, steam leak rates, and relief areas from-the rooms. Two flow models vere used -

Inertial Model, which is flow with inertia based on a solution of the one dimensional momentum equation, and Moody Flow Model, which is two phased water critical flow based on F.J. Moody, " Maximum Flow Rate of a Single Component,

• " COMPARE-MOD 1: A code for Transient Analysis of Volumes with Heat Sinks, Floving Vents, and Doors", LA-7199-MS, NRC-4, Los Alamos Scientific Laboratory, March, 1978.

• Attachunt 1 1 PY-CEI/NRR-1144 L

.Page 3 of 8 Two Phase Mixture" February 1965. Sensitivity analyses were performed, I varying the flow model, initial relative humidity, room cooling, and the flow path to the environment. For those calculations run with room coolers operatins it was assumed that the RCIC room cooler cooling water exhaust valve vas positioned to supply approximately 15 gpm flov from the Emergency Closed Cooling (ECC) system at all times, even with cold lake temperatures. This was done so that repositioning of this valve would not be required seasonally due to lake water temperatures. The previous submittal (PY-CEI/NRR-1124 L) had discussed that repositioning of this valve was difficult, and could have

. played a part in the undesired RCIC isolation on January 7. The conclusion I was that the Moody flow model yields the most conservative results while the l other parameters varied in the sensitivity analyses do not have a significant  ;

effect on the analysis.

From these calculations, RCIC room temperature rise versus time graphs were

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generated for various steam leak rates. These graphs indicated that for each steam leak rate the RCIC room temperature vould reach a maximum temperature within 1 to 5 minutes (these graphs assumed no isolations of the RCIC system occur, in order to examine room temperature responaes). Since this maximum RCIC air temperature vould be sensed by the vall mounted temperature detector (T of the RCIC room delta-T circuit, this value could be used in dekefm)iningvaliddelta-Ttripsetpointsforvariouslakewatertemperatures.

Two extreme cases had to be considered - cold vinter conditions, with only RCIC heat loads on ECC, and hot summer conditions, with other " post LOCA" heat loads on ECC conditions. For the cold vinter conditions, the temperature instrument logated in the RCIC room cooler exhaust (T would sense a  !

minimumof54Fbasedonalaketemperatureof33F.cQN)thehotsummer i conditions, the T instrument would sense a maximum temperature of 101"F  !

basedonalaketehNratureof80F. Having established T for hot and I cold conditions and using the Tho'sdiscussedabove,aseENNofdelta-T's forvarioussteamleakrateswas$evelopedforbothcoldandhotwater temperature conditions. I 1

Table 1 shows the delta-T values determined using this method for various H l steam leak rates. As shown on the Table, for any given steam leak rate, the 1 l differential temperature sensed by the delta-T instrumentation vould vary l l widely from the anticipated cold venther conditions to the hot weather j conditions. For example, Table 1 shows that a 5 gpm steam leak would result  ;

in a 29 F deltg-T during maximum anticipated sumiter conditions, but vould result in a 76 F delta-T during minimum vinter temperature conditions. i i

In order to establish one trip setpoint, CEI determined a range of steam leak  !

rates which vere considered acceptable to meet all regulatory requirements, -l and yet establish a trip setpoint large enough to prevent spurious trips even under various lake temperatures conditions. It was determined that establishing a Safety Limit differential temperature of 102 F would establish the bounding leak rates for automatic isolation as a range from just above 15 : q gpm in vinter to under 35 gpm in summer (see Table 1). From this safety limit value, an allovable value and trip setpoint were calculated taking into account instrument loop accuracies, instrument calibration accuracies, and l instrument loop drift. These calculations established the allowable value at 97.2 P and the trip setpoint at 95.9 F.

- Att:chment 1 PY-CEI/NRR-1144 L Page 4 of 8 Several important points vere considered in the process of selecting the 1 isolation setpoint and the 15-35 gpn tange of leakage which it vill serve to '

i isolate. First, the primary method provi6d h the RCIC Equipment Room for detection and isolation of small leaks is the RCIC Equipment Room Ambient i Temperature isolation instrumentation. ThL ambient room temperature isolation  ;

is the primary method of detecting small steam leaks in the RCIC Equipment '

Room because it isolates the RCIC system on a steam leak of approximately 15 gpm irrespective of lake temperature. The RCIC Equipment Room Ambient Temperature instruments ere independent, redundant instruments also monitoring for small steam leaks in the RCIC Equipment Room. The Technical Specification TripSetpointfortheAmbfentinstrumentationis143.4F. This is based on a Safety Limit value of 152 F. Based on the analysis described above for determining temperature rises in the RCIC equipment room for various steam leak rates, a leak of just above 15 gpm would increase the RCIC room temperature to the ambient safety limit value, regardless of the season. The delta-T instrumentation is consistent with this sensitivity level in the vinter, and remains adequately sensitive in the summer to remain bounded by the USAR analysis of the Main Steam Line Break outside containment discussed in USAR Section 15.6.4.

The RCIC toom temperature rise analyses discussed above indicated that RCIC Equipment Rogm differential temperature vould exceed the delta-T safety limit value of 102 P vithin 45 seconds with cold lake temperatures, and within 2.5 minutes with hot lake temperatures for a 35 gpm leak. The ambient detectors respond to provide an isolation even faster, with the ambient safety limit temperature belug exceeded within 35 seconds for a 35 gpm leak. Even so, if it was assumcd tnat a leak of 35 gpm continued for as long as 20 minutes prior to isolation, the resultant leakage released would be less than 4% of the leakage calculated in the MLB analysis. Therefore, the whole body dose and the inhalation dose vould be approximately 1.32% and .11% of 10CFR100 limits.

It is also noted that operators vould respond to investigate either ambient or delta-T alarms in the RCIC Equipment Room, alarms which have setpoints lover than the isolation setpoints. The alarm setpoint for both the RCIC Equipment Room ambient and delta-T instrumentation vill be established at approximately the 5 gpm range (as discussed above, for the delta-T Trip Setpoint, the alarm setpoint for delta-T vill actually cover a range of steam leaks based on lake water temperature vhile the ambient alarm setpoint will detect at 5 gpm year-round). The operators alarm response instruction notes that both of these alarms (ambient or differential) are caused by either eteam leaks from piping or components in the RCIC pump room, or by loss of ventilation in the room. The operators vould respond to these alarms _by taking actions to -

determine if a steam leak exists in the RCIC pump room. Depending upon the plant conditions existing at the time of the ambient or delta-T alarm, the operator vould take appropriate action to best protect the health and safety of the public. In determining the appropriate action, operators vould take into account whether the RCIC system was currently responding to perform its design function, and if so, what other systems vere available to perform a similar function. If the leak rate increased prior to the operator taking any manual action, the system would isolate at approximately 15 gpm due to the ambient temperature trip and at 15-35 gpm for the delta-T trip. As stated above all cases vould be bounded by the HSLB analysis in USAR Section 15.6.4.

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. Att:chment 1 i PY-CEI/NRR-1144 L Page 5 of 8 Finally, routine plant inspection programs vould most likely detect minor  !

steam leaks in the RCIC Equipment Room prior to either the ambient temperature or delta-T circuits reaching an alarm setpoint. Plant equipment rounds require that the RCIC Equipment Room be checked at least once per shift for leaks. The procedure requires the operator to correct the problem if he is able, or initiate a work request and notify the Control Room if the problem cannot be immediately fixed. Other items checked during these rounds are room sumps which would be an indirect indication of leaks in the room. In i addition, the Plant Rounds Instruction for Technical Specification Rounds requires that the RCIC Equipment Room Ambient temperature instruments and l delta-T instrument readings be channel checked and recorded each shift in accordance with Technical Specification requirements. This procedure also j requires that the Technical Specification rounds be reviewed for trends on a shift basis by the Unit Supervisor, and on a veekly basis by the Shift Supervisor and Operations Manager. Thus, steam leaks that vould cause room I temperatures to increase over a veekly period would be noted by these reviews, '

even if somehow missed by the operators performing the room inspections.

Inegnelusion,gdjustingthedelta-TTripSetpointandA11ovableValueto 95.9 F and 97.2 P is considered acceptable due to the following: ,

n. The range of leaks which will cause the RCIC system to automatically isolate on a delta-T Signal is small, and the leaks.are bounded by existing accident analyses.

b. The delta-T instrumentation is a backup to the ambient temperature instrumentation (the ambient temperature isolation is not being changed),

c. Existing procedures and programs monitor for steam leaks in the RCIC Equipment Room on a routine basis, and provide for operator response if alarms occur between routine inspection times.

No Significant Hazards Consideration

, The Nuclear Regulatory Commission (NRC) has promulgated standards in I 10CFR50.92(c) for determining whether a proposed amendment to a facility

( operating license involves no significant hazards considerations. A proposed amendment to an operating license involves no significant hazards considerations if operation of the facility in accordance with the proposed amendment vould nots (1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of a new or different kind of accident than previously evaluated; or l

(3) Involve a significant reduction in a margin of safety.

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AttCchment 1 PY-CEI/NRR-ll44 L Page 6 of 8 CEI has reviewed the proposed amendment with respect to these standards and has determined that the proposed changes do not involve a significant hazard because:

(1) The proposed change does not involve a significant increase in the probability or consequences of a previously evaluated accident.

The differential temperature isolation instrumentation provides monitoring for leaks. Therefore, the probability for leak initiation is not affected by the revision of the delta-T isolation setpoint.

The consequences of a previously evaluated accident also have not changed. The range of possible RCIC steamline breaks (up to and including a circumferential steamline break) is not affected by this proposed change. The leak detection isolation actuation instrumentation and alarms cover a vide range of steam piping breaks including both small leaks and large breaks in the RCIC line. As such any significant leak in the RCIC Equipment Room vill continue to be sensed by redundant and diverse instrumentation with appropriate setpoints for alarm and/or isolation capability. As such the consequences of a RCIC steamline break vill not change, and remain bounded by the steamline break outside of containment scenario analyzed in USAR Section 15.6.4. Thus, the consequences of a previously evaluated accident have not changed.

(2) The proposed change does not create the possibility of a new or different kind of accident from any accident praviously evaluated.

As stated above the differential temperature isolation actuation instrumentation is a monitoring system. Revision of the isolation setpoint of this monitoring system cannot create a new type of accident, since breaks of the RCIC steamline, up to and including a circumferential break, are bounded by other accidents presently analyzed in USAR Section 15.6.4.

(3) The proposod change does not involve a significant reduction in the margin of safety. There vill still exist sufficient redundant and diverse leak detection instrumentation with appropriate setpoints to detect steam leaks / breaks in the RCIC area. This change does not therefore affect any accident analysis nor does it have any adverse e'fect on performance characteristics of safety systems or accident consequences. As such it vill not result in a reduction in the margin of safety. Also, since this change vill increase the reliability of the RCIC system by reducing the possibility of an unnecessary isolation of RCIC vhen it is being called upon to restore reactor vater level, overall plant safety will be slightly increased.

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Att:chment 1 FY-CE1/NRR-1144 L Page 8 of 8 TABLE 1 DIFFERENTIAL TEMFERATURES CA14ULATED FOR VARIOUS STEAM LEAK RATES Leak Rate Calculated Ambient Calculated Differential (GPH) Temperatures Temperatures Year-Round Hot (Summer Conditions)* Cold (Vinter Conditions)*

5 130 F 29 F 76 F 0 0 10 146 F 45 F 92 F U

15 150 F 49 F 96 F 0 U 0 25 166 F 65 F 112 F 35 2260F 125 P 1720F Hot summer conditions equate to a Teold . 101 F, cold vinter conditions equate to a Teold - 54 P.

NJC/C0DED/3215 ,

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Att:chment 1 PY-CEI/NRR-1144 L Page 7 of 8 Environmental Consideration The Cleveland Electric Illuminating Company'has reviewed the proposed Technical Specification change against the criteria of 10 CFR 51.22 for environmental considerations. As shown above, the proposed change does not involve a significant hazards consideration, nor increase the types and amounts of effluents that may be released offsite, nor significantly increase individual or cumulative occupational radiation exposures. Based on the foregoing, CEI concludes that the proposed Technical Specification change meets the criteria given in 10 CFR 51.22(c)(9) for a categorical exclusion from the requirement for an Environmental Impact Statement.

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