ML17159A091
| ML17159A091 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 12/08/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML17159A090 | List: |
| References | |
| NUDOCS 9712190070 | |
| Download: ML17159A091 (22) | |
Text
gP,R RE00
~o OO lO0 gO
+**++
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20550-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.
TO FACILITY OPERATING LICENSE NO. NPF-14 MENDMENT NO. 144TO FACILITY OPERATING LICENSE NO. NPF-22 PENNSYLVANIA POWER
& L GHT COMP NY ALLEGHENY ELECTRIC COOPERATIVE INC.
SUS UEHANNA STEAM ELECTRIC ST TION UNITS 1
AND 2 DOCKET NOS.
50-387 AND 388
1.0 INTRODUCTION
By letter dated April 4,
- 1997, as supplemented April 14, June 6,
and September 2,
- 1997, Pennsylvania Power
& Light Company (PP&L), the licensee for Susquehanna Steam Electric Station (SSES),
Units 1 and 2, requested NRC's approval to implement amendments to its Facility Operating License NPF-14 for Unit 1 and NPF-22 for Unit 2 by incorporating changes to the SSES Units 1 and 2 Technical Specifications (TSs).
The requested changes would clarify the scope of the surveillance requirements for response time testing of instrumentation in the reactor protection system, isolation actuation
- system, and emergency core cooling, system in the TSs for each unit (Sections 4.3. 1.3, 4.3.2.3, and 4.3.3.3).
The April 14, June 6,
and September 2,
1997, letters provided clarifying information that did not change the original proposed no significant hazards consideration determination.
2.0 BACKGROUND
The Boiling Water Reactor Owner's Group (BWROG), with PPBL participation performed an analysis to assess the impact of elimination of response time testing (RTT) for selected instrument loops.
This analysis was documented as Licensing Topical Report NED0-32291, "System Analyses for Elimination of Selected
Response
Time Testing Requirements,"
and was submitted for NRC approval in January 1994.
The NRC approved NEDO-32291 (LTR) in a generic Safety Evaluation Report (SER) dated December 28,
- 1994, and approved subsequent revisions to NEDO-32291 in a supplemental SER dated May 31, 1995.
The generic SER included Tables 1 and 2, which respectively lists the make/model of instruments/devices, and systems which were evaluated in NEDO-32291 for RTT elimination.
The generic SER states, "The BWROG concluded that the RTT requirements for the devices identified in Table 1 can be removed from the TSs when the devices are used in systems listed in Table 2."
In addition to approving elimination of RTT for selected instrumentation, the generic SER stipulated certain conditions that individual plant licensees must meet when implementing the NEDO-32291 guidelines on a plant-specific basis.
qriazqO070 97<roe PDR ADQCK 05000387 P
<~ ~
g
3.0 PROPOS D
HANGES AND V LUATION PPKL proposed elimination of the following selected response time testing requirements from the SSES Units 1 and 2 TS:
1.
Reactor Protection System Instrumentation Sensors for Reactor Vessel Steam Dome Pressure-High and Reactor Vessel Low Mater Level - Level 3; 2.
Isolation Actuation System Instrumentation - Sensors for Reactor Vessel Low Mater Level-Level 1 and Hain Steam Line Flow-High, and; 3.
Emergency Core Cooling System Actuation instrumentation.
As approved by the NRC staff, NEDO-32291 indicated that response time testing can be eliminated for the following instrumentation based on other TS testing which is sufficient to detect instrumentation response degradation:
l.
All Emergency Core Cooling System instrument loops; 2.
All Isolation System Actuation Instrument loops except for main steam line isolation valves (HSIVs);
3.
Sensors for selected Reactor Protection System actuation; and 4.
Sensors for HSIV closure actuation.
3.1 Specific Changes The specific sections of the SSES Units 1 and 2 TS to be changed are as follows:
(a) Section 3/4.3. 1, Reactor Protection System Instrumentation, page 3/4 3-1, Surveillance Requirement 4.3. 1.3 currently states:
4.3.1.3 The REACTOR PROTECTION SYSTEH
RESPONSE
TIHE of each reactor trip functional unit shall be demonstrated to be within its limit at
.least once per 18 months.
Each test shall include at least one channel per trip system such that all channels are tested at least once every N times 18 months where N is the total number of redundant channels in a specific reactor trip system.
Pro osed Chan e'.
Modify the section to state:
4.3.1.3 The REACTOR PROTECTION to be within its limit units 2b, 2c, 3, 4, 5, shall include at least channels are tested at is the total number of trip system.
SYSTEH
RESPONSE
TIHE shall be demonstrated at least once per 18 months for functional 9 and 10 in Table 3.3.1-1.f Each test one channel per trip system such that all least once every N times 18 months where N
redundant channels in a specific reactor Add the following footnote:
0 Response time testing of sensors is not required for functional unit 4.
3 3 tl:
3 dttt Ttl 3.3.l-l,tltld'3 t
P.t tl tyt Instrumentation",
the functional units which will continue to be tested are:
2b. Avg. Power Range Monitor, Flow Biased Simulated Thermal Power-Upscale 2c. Avg. Power Range Monitor, Fixed Neutron Flux Upscale 3.
Reactor Vessel Steam Dome Pressure-High 4
Reactor Vessel Water Level - Low, Level 3
5.
Main Steam linedIsolation Valve Closure 9.
Turbine Stop Valve Closure
- 10. Turbine Control Valve Fast Closure, Trip Oil Pressure
- Low The functions in Table 3.3.1-1 which are not listed above, and therefore will not receive response time testing, are as follows:
la. Intermediate Range Monitors: Neutron Flux - High lb. Intermediate Range Monitors: Inoperative 2a.
Avg. Power Range Monitor: Neutron Flux Upscale, Setdown 2d. Avg. Power Range Monitor: Inoperativde 6.
Main Steam Line Radiation High 7.
Drywell Pressure - High Ba.
Scram Discharge Volume Water Level High: Level Transmitter 8b.
Scram Discharge Volume Water Level - High: Float Switch ll. Reactor Mode Switch Shutdown Position 12.
Manual Scram It is noted in Table 7.3-28 of the SSES Units 1 and 2 final safety analysis report (FSAR) that each of these functions has, as a response
- time, NA, and therefore no response time testing was done in the past.
There is no change for these functions as a result of this request.
The only change proposed to the reactor protection system (RPS)
RTT TS requirements is that the footnote will allow SSES Units 1 and 2 to use manufacturers response time data in lieu of actual testing data, and eliminate the requirement for an actual measurement of the sensor response time for Function 4,. Reactor Vessel Water Level - Low, Level 3.
The remainder of the Function 4 channel will continue to be tested for response time.
This change is consistent with the approved NED0-32291.
(b) Section 3/4.4, Surveillance Requirements, page 3/4 3-10, Surveillance Requirement 4.3.2.3, Isolation System
Response
Time, currently states:
4.3.2.3 The ISOLATION SYSTEM RESPONSE TIME of each isolation trip function shall be demonstrated to be within its limit at least once per 18 months.
Each test shall include at least one channel per trip system such that all channels are tested at least once every N
times 18 months where N is the total number of redundant channels in a specific isolation trip system.
Pro osed Chan e:
Modify the section to state:
4.3.2.3 The ISOLATION SYSTEM RESPONSE TIME shall be demonstrated to be within its limit at least once per 18 months for trip functions le, 3a, 3b, 3c, 3d, and 4a in Table 3.3.2-1.¹ Each test shall include at least one channel per trip system such that all channels are tested at least once every N times 18 months where N
is the total number of redundant channels in a specific isolation trip system.
Add the following footnote:
¹ Radiation detectors are exempt from response time testing for functions le and 3b.
Response
time testing of sensors is not required for functions 3a, 3c and 3d.
Response
time testing of isolating relays for Function 4a is not required.
Response
time testing of functions le and 3b (~10 second requirement) is not required.
The sensor response time testing requirement for functions le and 3b (glO second requirement) is met by testing the sensor to the
<1 second requirement of function 3b.
Evaluation:
According to the Table 3.3.2-1, titled "Isolation System Instrumentation",
the functional units which will continue to be tested are:
le. Primary Containment Isolation:
Main Steam Line Radiation, High 3a.
Main Steam Line Isolation: Reactor Vessel Water Level - Low,
- Low, Level 2
3b. Main Steam Line Isolation:
Main Steam Line Radiation - High 3c.
Main Steam Line Isolation:
Main Seam Line Pressure - 'Low 3d.
Main Steam Line Isolation:
Main Seam Line Flow - High 4a. Reactor Water Cleanup System Isolation:
RWCU ~ Flow High
Response
time testing of the radiation detectors for function le and 3b-was previously exempted, and as such, there is no change in this requirement.
Elimination of sensor testing for functions 3a, 3b, and 3c, elimination of relay RTT for functions le and 3b, and elimination of isolation relay RTT for function 4a is consistent with the approved NEDO-32291.
Sensor RTT for glO seconds for function le and 3b is redundant to the more restrictive
<1 second test requirement for function 3b, and is therefore, approved for elimination.
The footnote will allow SSES Units 1
and 2 to eliminate the requirement for a separate measurement of the response time for some components within the noted functions, and instead use manufacturers response time data when determining if the function
I
>s
~
meets response time requirements.
Because only certain specified components are exempted from RTT, the remainder of the channel will continue to be tested for response time.'he functions in Table 3.3.2-1 which previously were tested for their response
- times, but are not listed in the surveillance requirement
- above, and therefore will no longer receive response time testing, are as follows:
lal.
la2.
la3.
lb.
ld.
2a.
2b.
2c.
2d.
4e.
5a.
5b.
5j.
6a.
6b.
6j.
7a.
7e.
Primary Containment Isolation: Reactor Vessel Mater Level, Low, Level 3
Primary Containment Isolation: Reactor Vessel Mater Level, Low Low, Level 2
Primary Containment Isolation: Reactor Vessel Mater Level, Low Low Low Level I Primary Containment Isolation: Drywell pressure High Primary Containment Isolation:
SGTS Exhaust Radiation High Secondary Containment Isolation: Reactor Vessel Mater Level Low Low, Level 2
Secondary Containment Isolation: Drywell pressure - High Secondary Containment Isolation: Refuel Floor High Exhaust Duct Radiation High Secondary Containment Isolation: Railroad Access Shaft Exhaust Duct Radiation High Reactor Mater Cleanup System Isolation: Reactor Vessel Mater Level Low, Low, Level 2
Reactor Core Isolation Cooling System Isolation:
RCIC Steam Line SPressure
- High Reactor Core Isolation Cooling System Isolation:
RCIC Steam Supply Pressure - Low Drywell Pressure High High Pressure Coolant Injection System Isolation:
HPCI Steam line Pressure High High Pressure Coolant Injection System Isolation:
HPCI Steam Supply Pressure Low High Pressure Coolant Injection System Isolation:
Drywell Pressure - High RHR System Shutdown Cooling / Head Spray Mode Isolation:
Reactor Vessel water level - Low, Level 3
RHR System Shutdown Cooling / Head Spray Mode Isolation:
Drywell Pressure High This change to eliminate RTT for the above functions is consistent with the approved NEDO-32291.
In those cases where other requirements require testing of overall actuation response
- times, SSES Units I and 2 will be able to use manufacturers response time data for sensors and relays, and eliminate the requirement for actual measurement of the sensor and relay response time.
The remainder of the channel will continue to be tested for response time if such testing is required by other TS requirements.
0 a>
l
Those functions for which I) no credit was taken in the accident analysis,
- 2) the response time previously was "NA", therefore no testing for response time was done in the past, and no change to the surveillance requirement is needed, are as follows:
lc.
2e
~
2f.
3e.
3f.
3g ~
3h.
31.
4b.
4c.
4d.
4f.
4g, 5c.
5d.
5e.
5f.
5g.
5h.
5i.
6c.
6d.
6e.
6f.
6g.
6h.
6i.
7b.
Primary Containment Isolation:
Manual Initiation Secondary Containment Isolation: Refuel Floor Wall Exhaust Duct Radiation - High Secondary Containment Isolation:
Manual Initiation Main Steam Line Isolation:
Condenser Vacuum Low Main Steam Line Isolation: Reactor Building Main Steam Tunnel Temperature High Main Steam Line Isolation: Reactor Building Main Steam Tunnel
~Temperature High Main Steam Line Isolation:
Manual Initiation Main Steam Line Isolation: Turbine Building Main Steam Line Tunnel Temperature High Reactor Water Cleanup System Isolation:
RWCU Area Temperature - High Reactor Water Cleanup System Isolation:
RWCU Area Ventilation Temperature
~T - High Reactor Water Cleanup System Isolation:
SLCS Initiation Reactor Water Cleanup System Isolation:
RWCU Flow - High Reactor Water Cleanup System Isolation:
Manual Initiation Reactor Core Isolation Cooling System Isolation:
RCIC Turbine Exhaust Diaphragm Pressure - High Reactor Core Isolation Cooling System Isolation:
RCIC Equipment Room Temperature - High Reactor Core Isolation Cooling System Isolation:
RCIC Equipment Room Temperature High Reactor Core Isolation Cooling System Isolation:
RCIC Pipe Routing Area Temperature - High Reactor Core Isolation Cooling System Isolation:
RCIC Pipe Routing Area Temperature High Reactor Core Isolation Cooling System Isolation:
RCIC Emergency Area Cooler Temperature - High Reactor Core Isolation Cooling System Isolation:
Manual Initiation High Pressure Coolant Injection System Isolation:
HPCI Turbine Exhaust Diaphragm Pressure - High High Pressure Coolant Injection System Isolation:
HPCI Equipment Room Temperature - High High Pressure Coolant Injection System Isolation:
HPCI Equipment Room Temperature - High High Pressure Coolant Injection System Isolation:
HPCI Pipe Routing Area Temperature - High High Pressure
-Coolant Injection System Isolation:
HPCI Pipe Routing Area Temperature High High Pressure Coolant Injection System Isolation:
HPCI Emergency Area Cooler Temperature High High Pressure Coolant Injection System Isolation:
Manual Initiation RHR System Shutdown Cooling / Head Spray Mode Isolation:
Reactor
~ ~
~
h N.
n
Vessel 7c.
RHR System Shutdown Cooling / Head Spray Mode Isolation:
RHR Flow High 7d.
RHR System Shutdown Cooling / Head Spray Mode Isolation:
Manual Initiation (c) Section 3/4.3.3, Emergency Core Cooling System Actuation Instrumentation, page 3/4 3-27, Surveillance Requirement 4.3.3.3, ECCS Response
- Time, currently states:
4.3.3.3 The ECCS
RESPONSE
TIME of each ECCS trip function shall be demonstrated to be within the limit at least once per 18 months.
Each test shall include at least one channel per trip system such that all channels are tested at least once every N times 18 months where N is the total number of redundant channels in a specific isolation trip system.
d:
Edtyytt 1
t tt:
4.3.3.3 The ECCS
RESPONSE
TIME shall be demonstrated to be within the limit at least once per 18 months for trip functions la, lb, Ic, 2a, 2b, 2.c(1), 2.c(2),
3a, and 3b in Table 3.3.3-1.¹ Each test shall include at least one channel per trip system such that all channels are tested at least once every N times 18 months where N
is the total numbe} of redundant channels in a specific isolation trip system.
Add the footnote:
¹ Response time testing of sensors and relays is not required for these functions.
E 1 tt:
3 dt gt Ttt 3.3.3-1, titt d 3
g yt 3
Tt 3
System Actuation InstrumentationY, the functional units which will continue to be tested are:
la.
Core Spray System:
Reactor Vessel Mater Level - Low Low Low, Level I Core Spray System:
Drywell Pressure High Core Spray System:
Reactor Vessel Steam Dome Pressure - Low Low Pressure Coolant Injection Mode of RHR System:
Reactor Vessel Mater Level - Low Low Low, Level I 2b.
Low Pressure Coolant Injection Mode of RHR System:
Drywell Pressure - High 2cl.
Low Pressure Coolant Injection Mode of RHR System:
Reactor Vessel Steam Dome Pressure Low, System Initiation 2c2.
Low Pressure Coolant Injection Mode of RHR System:
Reactor Vessel Steam Dome Pressure - Low, System Initiation, Recirculation Discharge Valve Closure 3a.
High Pressure Coolant Injection System:
Reactor Vessel Mater
Level - Low Low, Level 2
3b.
High Pressure Coolant Injection System:
Drywell Pressure - High This change to elimnate RTT for the above functions is consistent with the approved NEDO-32291.
In those cases where other requirements require testing of overall actuation response
- times, SSES Units 1 and 2 will be able to use manufacturers response time data for sensors and relays, and eliminate the requirement for actual measurement of the sensor and relay response time.
The remainder of the channel will continue to be tested for response time if such testing is required by other TS requirements.
The remaining functions.in Table 3.3.3-1 are as follows:
1d. Core Spray System:
Manual Initiation 2d.
Low Pressure Coolant Injection Mode of RHR System:
Hanual Initiation 3c. High Pressure Coolant Injection System:
Condensate Storage Tank Level - Low 3d. High Pressure Coolant Injection System:
Reactor Vessel Mater Level High, Level 8
3e.
High Pressure Coolant Injection System:
Suppression Pool Mater Level - High 3f. High Pressure Coolant Injection System:
Hanual. Initiation 4a. Automatic Depressurization System:
Reactor Vessel Mater Level - Low Low Low, Level 1
4b. Automatic Depressurization System:
Drywell Pressure High 4c. Automatic Depressurization System:
ADS Timer 4d. Automatic Depressurization System:
Core Spray Pump Discharge Pressure - High 4e. Automatic Depressurization System:
RHR LPCl Node Pump Discharge Pressure High 4f. Automatic Depressurization System:
Reactor Vessel Mater Level-Low, Level 3
4g. Automatic Depressurization System:
ADS Drywell Pressure Bypass Timer 4h. Automatic Depressurization System:
Hanual Inhibit 4i. Automatic Depressurization System:
Hanual Initiation 5a.
Loss of Power:
- 4. 16 kV ESS Bus Undervoltage (Loss of Voltage < 20X) 5b.
Loss of Power:
4.16 kV ESS Bus Undervoltage (Degraded Voltage <
65X) 5c.
Loss of Power:
- 4. 16 kV ESS Bus Undervoltage (Degraded Voltage <
93X) 5d.
Loss of Power:
480V ESS Bus gB565 (Degraded Voltage < 65X) 5e.
Loss of Power:
480V ESS Bus gB565 (Degraded Voltage < 92X)
In Table 7.3-30 of the
- FSAR, each of the above functions has, "NA" as a
response time.
No RTT, was done on these functions in the past, and there is no change as a result of this proposed TS change.
3.2 Additional Instruments Not Listed in the Staff SER approving NEDO-32291 The licensee, in their request for elimination of RTT, included some sensors not specifically addressed in NED0-32291, and therefore not listed in Table 1
of the staff SER approving NEDO-32291.
The licensee's initial implementation of NEDO-32291 included two Barksdale sensor models (B2T-M12SS-GE and P1H series) not listed in NEDO-32291 or approved in the staff SER.
The licensee requested approval of these sensors based upon their similarity with the Barksdale model approved for RTT elimination in the SER for NED0-32291.
In the April 14, 1997, submittal, the licensee stated that they had determined that the only application at SSES for the B2T model device was in the Reactor Protection System Reactor Steam Dome High, Pressure function, for which sensor response time testing requirements have not been eliminated.
The request to eliminate RTT for this sensor was retracted.
In the June 6,
- 1997, submittal, PP&L reversed their previous retraction, and stated:
"The Barksdale B2T sensor should be included in the scope of response time testing eliminated in accordance with the LTR.
As described in previous submittals, the 82T was evaluated as part of PP&L's implementation of the LTR, and has been addressed in the LTR as an acceptable candidate for such replacement.
The B2T was included in PP&L's evaluation under 10 CFR 50.59 to preserve a replacement option for the B1T."
As justification for elimination of the Barksdale B2T sensor, in the June 6
submittal the licensee stated:
"The B1T sensor consists of a bourdon tube driving one microswitch.
Based on the approved LTR, there are no components that can cause response time related failures.
The B2T applications of interest consist of the exact configuration of a BlT, except the second microswitch is not in use.
In this case, the pressure source.is applied through the bourdon tube to the single microswitch.
There is no movement of the second microswitch, nor is there movement of any other internal part.
It is therefore PP8L's contention that the B2T sensor, using one microswitch, would have the same response time characteristic as the BlT sensor."
The second component for which the licensee requested elimination of RTT is the Barksdale PIH model sensor.
The licensee determined that the P1H sensor is similar to the Barksdale TC9622-3 sensor which was evaluated and listed in Table 1 of the staff SER approving NED0-32291.
As justification for elimination of the response time testing requirement for the Barksdale P1H sensor, the licensee stated in the April 14, 1997 submittal:
"Both the PlH and TC9622-3 utilize a piston type sensing element which actuates a microswitch.
Review of the FMEA for the TC9622-3 switch and follow-up with GE revealed that there are no potential failure modes of the mechanical portion of the PlH model device that would result in a sluggish response of the instrument.
The TC9622-3 model has a piston surrounded by an 0-ring. If the switch is misapplied in the process or
- range, the 0-ring seal can swell due to pressure above its rating and this swelling could cause the plunger pin (piston) to react sluggishly.
The PlH switch has a diaphragm which separates the process fluid from the switch internals (including the piston).
Its adjustment spring is separate
- from, and external to the piston, rather than adjoining as with the TC9622-3 model.
Therefore, the PlH model is not susceptible to the same stated failure mode as the TC9622-3 model.
As stated in the LTR, the only electrical failure mode (for the TC9622-3 model) occurs in the microswitch.
This will not produce a delay; but will cause failure to operate, which can be readily detected during surveillance testing.
This failure. mode could occur for the P1H switch as well but would similarly be detectable during surveillance testing.
A search was conducted using Nuclear Power Reliability Data System (NPRDS) for all reported failures of the Barksdale PlH sensor.
This data indicates that one possible potential failure mode that could result in a sluggish response is corrosion buildup on the plunger pin (piston).
As indicated by the recorded descriptions of the NPRDS failures, this failure mode can be detected by the functional tests and calibration tests."
Based upon these
- analyses, the licensee stated that the B2T and PlH sensors are bounded by the methodology described in NEDO-32291 which was approved as a
basis for RTT elimination.
The staff, after review of this information, agrees that there is no failure in the Barksdale B2T-M12SS-GE and Barksdale PIH sensors which can cause response time failure which will not also be detectable during calibration or other routine surveillance testing, and these sensors have characteristics similar to those of sensor models approved for
,RTT elimination.
Therefore, the staff approves the elimination of RTT for these
- sensors, subject to the conditions stated in the staff SER for NEDO-32291 applicable.,
3.3 Use of Anticipated Response Times Other Than Manufacturers Design
Response
Times The licensee stated that in some instances, manufacturers design response time data is not available for certain components.
In those instances, the licensee proposed using a response time value based upon actual values measured during past response time tests at SSES Units 1 and 2.
The licensee provided the data as Attachments 1 through 4 of the April 14, 1997, submittal.
In addition, the licensee stated:
"For those channels whose sensor response time tests have been eliminated, but for which relay response time testing is still required, an assumed administrative value for sensor response time is required."
These administrative values, or 'penalties,'ere invoked to account for the sensor response time in the total channel response time calculations.
This is applicable to the Reactor Protection System:
Reactor Vessel Water Level Low Level criteria, the Main Steam Line Isolation: Reactor Vessel
- Low channel and the Main Steam Line Isolation: Main.
Steam Line Flow High channel.
The table below lists each of these signals,,along with the total channel response time limit listed in the
- FSAR, and the administrative value for the sensor response time.
In order to determine an assumed administrative value for sensor response
- time, PP&L reviewed the operational history (i.e., the measured response times) since 1987.
(Note that the necessary "design" data from the manufacturer was not available.)
This data was evaluated to determine the longest sensor response time and the longest relay response time for each of the channels.
The sensor 'penalty'i.e.,
the now assumed sensor response time), was selected based upon the longest sensor and relay response times.
This 'penalty'alue was then added, to PP&L's procedures for calculating total channel response time.
For example, the longest instrument response time test result for the Reactor Protection System Reactor Vessel Low Level 3 channels (level switches A-D on both units) is 556 milliseconds.
For the purpose of establishing an administrative value for sensor response time testing, this number was rounded up to 600 milliseconds to determine the 'assumed penalty.
The relay response time test acceptance criterion is the remaining portion of the allowable channel response time (in this example, 1.05 seconds less 600 milliseconds, or 450 milliseconds).
Should the relay response time test results exceed this value, the channel would be declared inoperable and the appropriate TS LCO Action Statements would be entered.
k In response to a request from the NRC staff, PP&L performed an additional statistical analysis to ensure that the selected administrative values for sensor response time were conservative, based on the PP&L empirical data.
PP&L calculated a 95X confidence value, and concluded that the administrative limits assumed for the sensor response time were
~
conservative relative to the statistically-determined response times.
At the request of the NRC staff review, the attachment to this letter contains PP&L Calculation No. EC-05801011, "Sensor
Response
Time Values for Select RPS and MSIV Isolation Functions."
This calculation documents the statistical evaluation referenced
- above, and includes a compilation of the operational data used to support the derivation of administrative values.
Additionally, as discussed previously and at the April 10,
- 1997, teleconference, PP&L will submit a change to its ITS submittal, currently under review by the NRC, to describe that the administrative values established for the sensor response times for the four specific functions in question were derived from operational data.
The bases clarification will also indicate that this approach was taken due to the fact that the necessary "design" data from the manufacturer was not available."
PPSL submitted their proposed administrative values for response times in Attachment 1 to the June 14, 1997, submittal.
These values are as follows:
RPS Reactor Vessel Low Level 3
- 600 mSeconds MSIV Isolation Reactor Vessel Low Level 1: 600 mSeconds HSIV Isolation Main Steam Line Low Pressure:
100 mSeconds HSIV Main Steam Line High Flow: 200.mSeconds These administrative values were established based upon review of SSES operating historical response time data, selecting the longest, operational response time for the specific function, and rounding the time conservatively to an appropriate value.
The staff requested that PP&L determine a more statistically valid administrative value by determination of their mean and a
two sigma standard deviation value of response time (that value which represents a
95% confidence level by definition).
The staff then determined the one sided tolerance limit factor for a normal distribution for a 95/95X confidence level.
This was done using the guidance in "Applying Statistics",
NUREG-1475, Table T-lib:
One sided tolerance limit factor for a normal distribution.
The results of these calculations are shown below:
Sensor Function Mean Std Dev Mean + 2*Std Dev Sample Size One sided tolerance limit factor (95/95 Multiplier IAW NUREG 1475)
One sided tolerance limit SSES response time factor Sensor Function Mean Std Dev Mean + 2*Std Dev Sample Size One sided tolerance limit factor (95/95 Multiplier IAW NUREG 1475)
One sided tolerance limit SSES response time factor Sensor Function Mean Std Dev Barton 288A (GE 159C4384P003)
RPS Reactor Vessel low Level 3
452.8 64.8 582.4 24 2.309 602.4 600 ms Barton 760 MSIV Isolation Reactor Vessel Low Level 1
160.8 108.5 377.8 36 2.16
'95.2 600 mSeconds Barksdal e BIT-N12SS-GE HSIV Isolation Hain Steam Line Low Pres.
14.96 P
21.38 Mean + 2*Std Dev Sample Size One sided tolerance limit factor (95/95 Multiplier IAW NUREG 1475)
One sided tolerance limit SSES response time factor Sensor Function Mean Std Dev Mean + 2*Std Dev Sample Size One sided tolerance limit factor (95/95 Multiplier IAW NUREG 1475)
One sided tolerance limit SSES response time factor 57.7 24 2.309 64.4 100 mSeconds Barton 288A (GE 145C009P001)
HSIV Hain Steam Line High Flow 56.8 41.4 139.6 39 2.12 144.6 200 mSeconds In each case, except for the RPS Reactor Vessel Low Level 3 function, the SSES response time factor is more conservative than the one sided tolerance limit calculated by the staff, and is therefore acceptable to the staff.
In the case of the RPS Reactor Vessel Low Level 3 function, the SSES response time factor and the staff calculated one sided tolerance limit are within 2.4
- mSeconds, less than qX of the anticipated response
- time, and therefore, the SSES response time factor of 600 mSeconds is acceptable to the staff.
The difference in the response time characteristics in the two Barton 288A
- sensors, with a mean of 452.8 mSeconds when used in the RPS Reactor Vessel Low Level 3 function, as opposed to a mean of 56.8 mSeconds when used in the HSIV Hain Steam Line High Flow function, is due to differing physical characteristics of the two sensors.
When used in the RPS function, the Barton 288A with a GE part number of GE 159C4384P003 has a range of 0-60",
and therefore a bellows diameter of 1.625 inches.
The Barton 288A sensor used in the HSIV function has a range of 0-150 psid, and due to the larger pressure differential, has a bellows diameter of.75 inches.
PP&L stated, in their September 2,
1997, submittal:
"PP&L purchases these component from GE, not from Barton.
The GE purchase part drawing numbers are not unique to PP&L, but to GE.
Because PP&L orders the components directly from GE, Barton identifying information is not used.
Therefore, PP&L has no additional identifying-information by which the NRC reviewer can refer to the two 288A applications."
Since it appears that Barton 288A sensors can have a significant variation in their anticipated response
- times, and that the differences in th'e models is unique to GE part numbers, the use of these administrative values for Barton 288A sensors is limited to the reviewed uses, and may not be used in other applications proposed for RTT elimnation without further staff review.
4.0' RIFI T ON OF N DO-322 PLANT-SPEC D T 0 S
The staff stipulated several conditions in the generic SER approving NEDO-32291 which must be met by the individual licensee referencing NEDO-32291 before its guidance could be implemented in plant-specific TS change proposals.
From the SSES Units 1 and 2 licensee's submittals, the staff verified that the licensee'as met the applicable conditions as follows:
- 4. 1
$:ondi~t
- Confirm the applicability of the generic analyses to the plant.
Licensee's R s o
s
- In the September 2,
1997 letter, (PLA-4648),
on page 8 of 13 of attachment 1, the licensee stated:
"PP8L has reviewed the LTR analyses to confirm that all analyses pertain to the design basis of SSES."
The staff concurs with this response.
4.2
~Conditio
Licensee's Res onse:
The licensee stated that the March 26, 1997, submittal for proposed TS changes satisfies this condition.
The staff concurs with this response.
4.3
~Conditio
- The licensee shall state that they are following the recommendations from EPRI NP-7243 and, therefore, shall perform the following actions:
(a) Prior to installation of a new transmitter/switch or following refurbishment of a transmitter/switch (e.g.,
sensor cell or variable damping components),
a hydraulic RTT shall be performed to determine an initial sensor-specific response time value.
Licensee Res onse:
"Training has been provided to appropriate Engineering personnel and Instrumentation 8 Control (I&C) personnel to assure familiarity with this requirement.
Appropriate plant modification and I&C procedures were revised to include this requirement."
The staff concurs that this response meets the above conditions.
(b) For transmitters and switches that use capillary tubes, capillary tube testing shall be performed after initial installation and after any maintenance or modification activity that could damage the capillary tubes.
Licensee Res onse:
"Training has been provided to appropriate Engineering personnel and Instrumentation 8 Control (I&C) personnel to assure familiarity with this requirement.
Appropriate plant Modification and I8C procedures were revised to include this requirement."
The staff concurs with this response.
4.4 Condition
The Licensee must confirm the following:
(a) That calibration is being done with equipment designed to provide a
step function or fast ramp in the process variable.
Licensee Res onse:
"Existing procedures were determined to be adequate for those instruments with an internal indicator.
For blind switches (Static 0
Ring, Barksdale),
a post-calibration functional response time test has been added to the calibration procedures.
This test provides a fast ramp signal to the instrument at plus-or-minus 10 percent of the setpoint.
This is done as part of the calibration on an 18-month basis."
The staff concurs that this response meets the above condition.
(b) That provisions have been made to ensure that operators and technicians, through an appropriate training program, are aware of the consequences of instrument response time degradation, and that applicable procedures have been reviewed and revised as necessary to assure that technicians monitor for response time degradation during the performance of calibrations and functional tests.
Licensee Res onse:
"Training has been provided to Operations and 18C personnel to assure familiarity with this requirement.
A statement requiring that technicians monitor for response time degradation during the performance of calibrations and functional tests has been added to the applicable test procedures as a standard prerequisite."
The staff concurs that this response meets the above conditions.
(c) That surveillance testing procedures have been reviewed and revised if necessary to ensure calibrations and functional tests are being'erformed in a manner that allows simultaneous monitoring of both the input and output response of units under test.
Licensee Res onse:
"Functional tests and calibrations were reviewed and determined to be performed in a manner that allows simultaneous monitoring of both the input and output response of the units." The staff concurs that this response meets the above conditions.
(d) That for any request involving the elimination of RTT for Rosemount pressure transmitters, the licensee is in compliance with the guidelines of Supplement 1 to Bulletin 90-01, "Loss of Fill-Oil in Transmitters Manufactured by Rosemount."
"N ti b
th R
t transmitters in any of the loops where response time testing was eliminated by applying the GE LTR methodology."
The staff concurs that since there are no Rosemount transmitters affected by this request, this condition is not applicable.
(e) That for those instruments where the manufacturer recommends periodic RTT as well as calibration to ensure correct functioning, the
ly licensee has ensured that elimination of RTT is nevertheless acceptable for the particular application involved.
R: 'I I
f EPRI R
P t IIP-IREE, 'I ttt tt f
Response
Time Testing Requirements" and calls to various vendors ensured that the above statement was performed.
No manufacturer of the instruments for these applications recommends periodic response time testing."
The staff concurs that this response meets the above conditions.
Based upon the above review, the staff concludes that the licensee has implemented the provisions of the generic SER for RTT elimination in accordance with NEDO-32291 and has satisfactorily justified RTT elimination for those components not addressed in NEDO-32291.
Therefore, the staff concludes that the proposed SSES Units 1 and 2 TS modifications for selected instrument RTT elimination are acceptable.
- 5. 0 STAT CONSULTATION In accordance with the Commission's regulations, the Pennsylvania State official was notified of the proposed issuance of the amendments.
The State official had no comments.
- 6. 0 ENVIRONMENTAL CONSIDERATION The amendments change a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and change surveillance requirements.
The NRC staff has determined that the amendments involve no significant increase in the amounts',
and no significant change in the types, of any effluents that may be released
- offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a
proposed finding that the amendments
)nvolve no significant hazards consideration, and there has been no public comment on such finding (62 FR 17885).
Accordingly, the amendments meet eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
7.0 CONCLUSION
The Commission has concluded, based on the considerations discussed
- above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed
- manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
P.
Loeser Date:
December 8, 1997
C 4