ML20140C771
| ML20140C771 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 03/05/1986 |
| From: | Gears G Office of Nuclear Reactor Regulation |
| To: | Bauer E PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| References | |
| GL-83-28, NUDOCS 8603250481 | |
| Download: ML20140C771 (5) | |
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Docket Nos. 50-277/278 DISTRIBUTION RBernero Geeke+4He, ACRS (10) 3 NRC POR 0 ELD Local PDR Edordan Mr. Edward G. Bauer, Jr.
ALAR 0 5 E E Rusg BGrimes Vice President and General SNorris-JPartlow Counsel GGears Gray File i
Philadelphia Electric Company 2301 Market Street
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Philadelphia, PA 19101
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Dear Mr. Bauer:
SUBJECT:
COMMENTS ON THE PHILADELPHIA ELECTRIC COMPANY GENERIC LETTER 83-28 RESPONSE OF OCTOBER 16, 1985 3
Re:
Peach Bottom Atomic Power Station, Units 2 and 3 The Philadelphia Electric Company (PECo) responded to Generic Letter 83-28 i
by letter dated November 4,1983. Their response to Item 1.2, Data and Information Capability, was evaluated by the NRC staff and its contractor, Science Applications International Corporation (SAIC). By memo dated July 10, 1985, a Safety Evaluation covering the review was transmitted to PECo. The SE concluded that PEco's post-trip review data and information capability for Peach Bottom Atomic Station may be inadequate to permit diagnosing the causes of unscheduled reactor shutdowns and for determining the proper functioning of safety-related equipment.
PECo responded to our review of their data and information capability by 1
letter dat" October 16, 1985. This response informed us that PECo believes that their existing data and information capabilities are adequate to perform a post-trip review. However, they are planning to update this capability to provide basically all of the review capability recomended in our SE. This update is to be made by way of a planned computer upgrade, i
However, this upgrade (late 1989 to mid-1990) is considerably far in the future. We recommend that PECo explore some form of interim measure to i
improve their data and information capability until the upgraded computer is i
available.
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Our comments on the PECo letter of October 16, 1975, follow:
1 1.
We noted that the time-history recorder sampling interval of 60 i
seconds was much longer than the recommended 10 second interval, and i
that the slow (2 cm/hr) strip chart recorder speed did not permit adequate time discrimination for post-trip review. The licensee j
response was:
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"The combined capabilities of the post-trip log, sequence of events j
log, and strip chart recorders provide the information necessary to perform.the post-trip review. The 60-second interval on the post-trip log provides a gross overview of the event. The strip chart recorders identify any significant variations in the parameters not reflected on the post-trip log. Additionally, the sequence of events log is j
utilized to determine those parameters which experience significant deviations in values.
"The 2 cm/hr strip chart speed does not affect its primary function, which is to analyze the magnitude of the parameter's deviation. The i
time at which a significant deviation occurs is obtained from the sequence of events log data."
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The PECo response does not' alter our concern that the post-trip records will not provide an adequate post-trip time-history to diagnose some 1
unscheduled reactor shutdowns. We do not believe that a combination of a.
" gross overlook" plus "the magnitude of a _ parameter's deviation" serves to describe the time-history of selected parameters from 5 minutes pre-trip to at least 10 minutes post-trip. Basically, the PECo 10-minute post-trip history for any given parameter will consist of ten 1-minute-interval parameter values, and approximately one-eighth inch of ' strip chart. The recommended parameters to be monitored for post-trip history values include neutron flux, containment radiation, drywell pressure, suppression pool-temperature, primary system pressure, pr.imary system level, feedwater flow, steam flow, recirculation flow and safety injection flow. With few exceptions, evaluation of the post-trip performance of these parameters will require more than a once-per-minute record of parameter values plus a possible maximum / minimum data point which probably cannot be correlated j
with the time of the trip.
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We noted that PECo does not record data for a number of parameters that were recommended as being important for post-trip analyses. The PECo responses and our comments on those responses follow; a.
Sequence of Events Recorder
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1.
Safety Injection:
"The initiating signals are logged in j
lieu of the logic output signals for HPCI and RCIC. One of the two initiating signals (High Drywell Pressure) for LPCI and core spray is logged and the other signal (reactor water level) is recorded on the post-trip log. This combination provides the information necessary to perform the post-trip review."
Only reactor trip initiating signals will be recorded on the SOE, and safety injection will be inferred from these signals.
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There will be no record of the time of safety injection.
Without this information, we question PECo's ability to correctly diagnose the proper functioning of the safety injection equipment. Using the post-trip log record of reactor water level to determine safety injection status j
will not provide the time of safety injection. This log provides parameter data only once per minute.
1 2.
Containment Isolation:
"The initiating signals of primary containment isolation (i.e., drywell pressure: main steam i
line high flow, high radiation, and leak detection; and j
reactor water level - lo and 10-10) are logged in lieu of the logic output signals."
l As before, there is no record of the time when isolation j
valves are closed.(or, in fact, that they are closed).
Lacking this data, we do not see how it will be possible to i
accurately or correctly diagnose the proper functioning of this equipment following a reactor trip and an isolation signal.
3.
Control Rod Position:
" Adequate post-trip review has been l
possible without this parameter."
We do not find this an adequate justification for not recording this parameter.
4.
Turbine Bypass Valve Position:
"The function of this data l
in post-trip review of boiling water reactors is not apparent."
We believe that this data is important to some post-trip
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reviews, and observe that most BWR facilities that have been reviewed for post-trip data and information capability do record this parameter. Without this position data, would PECo have enough recorded information to assess all reactor trips on high pressure that followed closure of.the turbine j
stop valve?
5.
Recirculation Pump Status, AC and DC System Status: We had no problems with the post-trip records for this parameters.
6.
Safety Injection Flow:
"The reactor Water Level strip charts are utilized to ascertain pump flow."
Reactor Water Level is recorded on a 2 cm/hr strip chart l
recorder.
It is not possible to determine the time response of safety injection flow with this type and quality of-data.
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. b.
Post-Trip Log j
PECo has responded to our pre-SER comments to report that containment Radiation, Suppression Poo1' Temperature and Drywell Pressure will be recorded on strip charts. As previously noted, the time of events cannot be determined with any degree of accuracy from a 2 cm/hr strip chart. Consequently, the time at which, e.g., containment radiation exceeded its maximum safe value could not be established with the accuracy that would be needed to diagnose a subsequent safety function action.
(At 2 cm/hr, the time for the strip chart to move one one-hundredth of an inch -
about the limit of strip chart reading accuracy - is some 45 seconds).
In addition, the recommendation for Drywell Pressure was that an actual pressure-vs-time-history be developed. This is not possible with a 2 cm/hr chart speed, j
3.
We commented on the readability of the 2 cm/hr strip chart records.
j PECo responded that "The response to the first deviation regarding 1
strip chart recorder speed is applicable to this deviation. The strip i
chart output is primarily used for analysis of the magnitude of the j
parameter's deviation. The time at which the deviation occurs is i
obtained from the sequence of events log data."
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Our comments in Items 1 and 2 above also apply here where they relate i
to strip chart problems. We note that the PEco comment - that strip 1
chart data is used for magnitude only - supports our contention that the 2 cm/hr strip charts cannot be used for time-history records.-
Also, there does not appear to be a one-to-one correlation between SOE j
and strip chart parameters, nor are we convinced that adequate time j
correlation can be made between the two recorder types, J
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Summing up, Generic Letter 83-28 calls for a licensee data and information capability to " correctly diagnose -- the proper functioning of safety-related equipment -." We review "to determine whether adequate data and information j
will be available to support the systematic safety assessment of unscheduled j
reactor shutdowns." For this case, we remain concerned that the licensee's post-trip review data and information capabilities for Peach Bottom Units 2 j
and 3 may be inadequate for diagnosing the cause of unscheduled reactor j
shutdowns and for ascertaining the proper functioning of safety-related l
equipment. Further, we do not believe that the PECo submittal of October 16, 1985 has provided justification for the adequacy of the equipment now being used for diagnosing unscheduled reactor shutdowns. We are aware that PECo j
intends to upgrade their post-trip data and information capability, and expect that the upgraded systems will comply with the review guidelines described in the NRC input of July 10, 1985. However, the implementation l
dates for the upgraded systems (late 1989 - mid-1990) result in an
' excessively long time period during which PECo may not be able to conduct i
or complete post-trip reviews of some unscheduled reactor shutdowns.
It is i
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difficult to make recommendations as to interim measures that PECo could j
adopt to improve-their data and information capability.
Ideally, the upgraded system should be installed on a much shorter time scale. Other than that, the missing parameters could be recorded (on existing 4
instrumentation or on new equipment) on a shorter timescale, and the strip chart recorder speeds could be increased - say from 2 to 10 cm/hr. This would provide a better time-history for those parameters now recorded on l
strip charts, l
In order to attempt to resolve the above concerns, we would'like to meet
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with PECo personnel at some time in the near future and review with your staff the filed data and information packages that have been assembled and I
used by PECo personnel to review and diagnose some of the more recent Peach
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Bottom Units 2 and 3 unscheduled reactor shutdowns. The object of this j
meeting would be to gain more insight into how you might be able to undertake a diagnosis of possible unscheduled reactor trips resulting j
from potentially more obscure causes.
If'you have any questions, please contact me at 301-492-4993 j
Sincerely, Oric!nal sic ~nad by,
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raid E. Gears, Project Manager.
l BWR Project Directorate #2 i
u Division of BWR Licensing I
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Mr. E. G. Bauer, Jr.
Peach Bottom Atomic Power Station, Philadelphia Electric Company Units 2 and 3 CC:
Mr. Eugene J. Bradley Mr. R. A. Heiss, Coordinator Assistant General Counsel Pennsylvania State Clearinghouse Philadelphia Electric Company Governor's Office of State Planning 2301 Market Street and Development Philadelphia, Pennsylvania 19101 P.O. Box 1323 Harrisburg, Pennsylvania 17120 Troy B. Conner, Jr., Esq.
1747 Pennsylvania Avenue, N.W.
Mr. Thomas M. Gerusky, Director Washington, D.C.
20006 Bureau of Radiation Protection Pennsylvania Department of Thomas A. Deming, Esq.
Environmental Resources Assistant Attorney General P.O. Bo' 2063 x
Department of Natural Resources Harrisburg, Pennsylvania 17120 Annapolis, Maryland 21401 Mr. Albert R. Steel, Chairman Philadelphia Electric Company Board of Supervisors ATTN:
Mr. R. Fleishmann Peach Bottom Township Peach Bottom Atomic R. D. #1 Power Station Delta, Pennsylvania 17314 Delta, Pennsylvania 17314 Mr. M. J. Cooney, Superintendent Generation Division - Nuclear Philadelphia Electric Company 2301 Market Street Philadelphia, Pennsylvania 19101 Mr. Anthony J. Pietrofitta, General Manager Power Production Engineering Atlantic Electric P. O. Box 1500 1199 Black Horse Pike Pleasantville, New Jersey 08232 Resident Inspector U.S. Nuclear Regulatory Commission Peach Bottom Atomic Power Station P.O. Box 399 Delta, Pennsylvania 17314 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 6J1 Park Avenue King of Prussia, Pennsylvania 19406
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