ML20210K248
| ML20210K248 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 04/22/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20210K241 | List: |
| References | |
| GL-83-28, NUDOCS 8604280064 | |
| Download: ML20210K248 (6) | |
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NUCLEAR REGULATORY COMMISSION WASHINGTON D. C. 20555 h
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGU RELATING TO GENERIC LETTER 83-28, ITEM 1.2 - POST-TRIP REVIEW DATA AND INFORMATION CAPARILITY GPU NUCLEAR CORPORATION JERSEY CENTRAL POWER AND LIGHT COMPANY OYSTER CREEK NUCLEAR GENERATING STATION DOCKET NO. 50-719 1.0 INTRnDUCTInN both of the scram circuit breakers at Unit 1 of the On February 25, 1983, Salem Nuclear Power Plant (SNPP) failed to open upon an automatic reactor This incident occurred trip signal from the reactor orotection system.
durino the plant startuo and the reactor was tripped manually by the operator about 30 seconds after the initiation of the automatic trio The failure of the circuit breakers has been determined to be Prior to this signal.
related to the sticking of the undervoltage trip attachment.during startup of S incident on February 22, 1983, In this trip signal was oenerated based on steam generator low-low level.
case, the reactor was tripped manually by the operator almost coincidentally Following these incidents, on February 28, 1983, with the automatic trip.
the NRC Executive Director for Operations (EDO) directed the staff to investigate and report on the generic implications of these occurrences at The results of the staff's inquiry into the generic SNPP Unit 1.
implications of the SNPP units incidents are reported in NU As a result of this investigation, the Commission (NRC) requested (by Generic letter 83-28 dated JJ1y 8, 1983) all licensees of operating reactors, applicants for an operating license, and holders of construction These concerns are permits to respond to certain generic concerns.(1) Post-Trip Review, (2) Eauipment categorized into four areas: Classification and Vendor Interface, (3) Post-Mainten (4) Reactor Trip System Reliability Improvements.
The first action item, Post-Trip Review, consists of Action Item 1.1,
" Data and
" Program Description and Procedure" and Action item I.?.This safety eva Information Capability."
only.
14, 1985, Action Item 1.1 was evaluated by the staff in its letter dated May in which the staff concluded the licensee's response to item 1.1 was acceptable.
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?.0 REVIEW GUIDELINES The following review ouidelines were developed after initial evaluation of the various utility responses to item 1.2 of Generic letter 83-28 and incorporate the best features of these submittals. As such, these review guidelines in effect represent a " good practices" approach to post-trip review, data and information capability. The NRC staff has reviewed the licensee's response to Item 1.2 against these guidelines:
The equipment that provides the digital sequence of events (50E) record A.
and the analog time history records of an unscheduled shutdown should provide a reliable source of the necessary information to be used in the Each plant variable which is necessary to determine post-trip review.
the cause and proaression of the events following a plant trip should be monitored by at least one recorder (such as a sequence-of-events recorder or a. plant process computer) for digital parameters; and monitored by at least strip charts, a plant process computer or an analog recorder for analog (time history) variables. Performance characteristics guidelines for SOE and time history recorders are as follows:
Each sequence of events recorder should be capable of detecting and recording the secuence of events with a sufficient time discrimination capability to ensure that the time responses associated with each monitored safety-related system can be ascertained, and that a determination can be made as to whether the time response is within acceptable limits based on Final The Safety Analysis Report (FSAR) Chapter 15 Accident Analyses.
recommended guidelines for the SOE time discrimination is If current SOE recorders do not aporoximately 100 milliseconds.
[
have this time discrimination capability, the licensee should show that the current time discrimination capability is sufficient for an adequate reconstruction of the course of the reactor trip As a minimum this should include the and post-trip events.
i ability to adequately reconstruct the transient and accident scenarios presented in Chapter 15 of the plant FSAR.
Each analog time history data recorder should have a sample
- i interval small enough so that the incident can be accurately reconstructed following a reactor trip. As a minimum, the licensee should be able to reconstruct the course of the transient and accident sequences evaluated in the accident The recommended analysis of Chapter 15 of the plant FSAR.
If the tima quideline for the sample interval is 10 seconds.
history equipment does not meet this cuideline, the licensee 5
I should show that the time history capability is sufficient to accurately reconstruct the transient and accident secuences presented in Chapter 15 of the FSAR. To support the post-trip
[
analysis of the cause of the trip and the proper functioning of involved safety-related equipment, each analog time history data i
recorder should be capable of updating and retaining information 1
from approximately 5 minutes prior to the trip until at least i
10 minutes after the trip.
i
'i hEpeet
. All equipment used to record sequence of events and time history information should be powered from a reliable and non-interruptible The power source used need not be Class 1E.
power source.
The sequence of events and time history recording equipment should monitor sufficient digital and analog parameters, respectively, to assure B.
that the course of the reactor trip and post-trip events can be The parameters monitored should provide sufficient reconstructed.
information to determine the root cause of the unscheduled shutdown, the progression of the reactor trip, and the resoonse of the plant paraneters and protection and safety systens to the unscheduled Specifically, all input parameters associated with reactor shutdowns.
trips, safety injections and other safety-related systems as well as output parameters sufficient to record the proper functioning of these The systems should be recorded for use in the post-trip review.
parameters deemed necessary, as a minimum, to perform a post-trip review that would determine if the plant remained within its safety limit design envelope are presented in Table 1.
They were selected on the basis of staff enoineering judoment following a complete evaluation of utility submittals. If the licensee's SOE recorders and time history recorders do not monitor all of the parameters suagested in these tables, the licensee should show that the existing set of monitored parameters are sufficient to establish that the plant remained within the design envelope for the accident conditions analyzed in Chapter 15 of the plant FSAR.
The information gathered by the sequence of events and time history recorders should be stored in a manner that will allow for data re C.
The data may be retained in either hardcopy, (e.g., com-and analysis.
puter printout, strip chart record), or in an accessible memory (e.g.,
This information should be presented in a read-magnetic disc or tape).
able and meaningful format, taking into consideration cood human factors practices such as those outlined in NUREG-0700.
Retention of data from all unscheduled shutdowns provides a valuable reference source for the determination of the acceptability of the plant D.
vital parameter and equipment response to subseouent unscheduled Information gathered during the post-trip review is to be retained for the life of the plant for post-trip review comparisons of shutdowns.
subsequent events.
3.0 EVALUATION GPU Nuclear Corporation (the licensee) 14, 1983, Ry letter dated Novemberorovided information regardino its post-trip review pr The information capabilities for Oyster Creek Nuclear Generating Station.
staff has evaluated the licensee's submittal against the review guidelines l
Deviations from the Guidelines were discussed described in Section 2.0.
20, 1985. A with representatives of the licensee by telephone on Decemb the responses against each of the review guidelines is as follows:
_a_
The licensee has described the performance characteristics of the equipment used to record the sequence of events and time history data A.
Based on our review of the licensee's needed for post-trip review.
submittal, the staff finds that the sequence of events recorder and time history characteristics conform to the guidelines described in Section 2. A, and, therefore, are acceptable.
The licensee has established and identified the parameters to be Based on its review, R.
monitored and recorded for post-trio review.
the staff finds that the parameters selected by the licensee include all of those identified in Table 1 and conform to the guidelines described in Section 2.8 and, therefore, are acceptable.
The licensee described the means for storace and retrieval of the C.
information gathered by the sequence of events and time history recorders, and for the presentation of this information for post-trip Rased on its review, the staff finds that this review and analysis.
information will be presented in a readable and meaningful format, and that the storace, retrieval and presentation conform to the cuidelines of Section ?.C and, therefore, are acceptable.
20, 1985, the licensee Durino the phone conversation of December indicated that the data and information used during post-trip reviews D.
is being retained in an accessible manner for the life of the plant.
Based on this information, the staff finds that the licensee's procram for data retention conforms to the guidelines of Section 2.0, and is, therefore, acceptable.
4.0 CONCLUSTON the Based on its evaluation presented above, the staff concludes that licensee's post-trip review, data and information capability, for Oyster Creek is acceptable.
5.0 REFERENCES
Letter from P. B. Fiedler, GPU Nuclear, to Director, Division of 1.
Licensing,ilSNRC, dated November 14, 1983.
Telephone conversation between J. Donohew and J. Kramer, USNDC, and 2.
M. Laogart, GPU Nuclear, dated December 20, 1985.
Principal Contributor:
J. Kramer Dated:
April 22, 1986.
1
TABLE 1 BWR PARAMETER LIST SOE Time History Recorder Recorder Parameter / Signal Reactor Trip x
Safety Injection x
Containment Isolation x
Control Rod Position x
x (1) x Neutron Flux, Power x (1)
Main Steam Radiation (2)
Containment (DryWell) Radiation Drywell Pressure (Containment Pressure) x (1) x (2)
Suppression Pool Temperature j
x (1) x Primary System Pressure x(1) x Primary System Level
~
MSIY Position x
x(1)
Turbine Stop Valve / Control Valve Position Turbine Bypass Valve Position x
Feedwater Flow x
x Steam Flow (3)
Recirculation; Flow. Pump Status x (1)
Scram Discharge Level x(1)
Condenser Vacuum i
SOE Time History Recorder Recorder Parameter / Signal (3)
Auxiliary Feedwater System: Flow.
Pump / Valve Status AC and DC System Status (Bus Voltage) x Diesel Generator Status (Start /Stop, x
On/Off)
PORV Position x
(1)
Trip parameters (2)
Parameter may be monitored by either an SOE or time history recorder.
. (3)
Acceptable recorder options are; (a)systemflowrecordedonanSOE recorder (b) system flow recorded on a time history recorder, or (c) lequipment status recorded on an SOE recorder.
S
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