ML18052A589
| ML18052A589 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 06/30/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18052A588 | List: |
| References | |
| GL-83-28, NUDOCS 8607100039 | |
| Download: ML18052A589 (9) | |
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I UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION GENERIC LETTER 83-28, ITEM 1.2 - POST-TRIP REVIEW (DATA AND INFORMATION CAPABILITY)
CONSUMERS POWER COMPANY PALISADES NUCLEAR PLANT DOCKET NO. 50-255 INTRODUCTION On February ?.5, 1983, both o~ the scra~ circuit breakers at Unit 1 of the Salem Nuclear Power Plant (SNPP) failed to npen upon an automatic rPactor trip siqnal from the reac~or prot~ction system.
This incident occurred d11ring the plant start-u~ and the reactor was tripped manually hy the operator about 30 seconds after the initiation of the automatic trip signal.
The failure of
.~
the circuit breakers has been determined to he related to the sticking of the undervoltage trip attachme11t.
- On February 22, 1983, during start-up of SNPP, Unit l, an automatic trip signal occurred as the result of steam generator low-low level.
In this case,* the reactor was tripped manually by the operator almost coincidentally with the automatic trip.
Following these incidents, on February 28, 1983, the NRC Executive Director for Operations (EDO) directed the staff to investigate and report on the generic implications of these occurrences.
The results of the staff's inquiry into these incidents are re-ported in NUREG-1000, "Generic Implications of ATWS Events at *the Salem Nuclear Power. Plant."
As a result of this investigation, the Commission requested (by Generic Letter 83-28 dated July 8, 1983) all licensees of operating reactors, applicants for an operating *license, and holders of construction pennits to respond to certain generic concerns.
These concerns are categorized.into four areas: (1} Post-Trip Review, (2) Equipment Classification and Vendor Interface, (3) Post-Maintenance Testing, and (4) Reactor Trip System Reliability Improve..
ments.
B607100039 860630 I
PDR ADOCK.0500025_5~t\\
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. PDR
- The first action item, Post-Trip Review, consists of Action Item 1.1, "Program Description and Procedure" and Action Item 1.2, "Data and Information Capability." This safety evaluation (SE) addresses Action Item 1.2 only.
II.
REVIEW GUIDELINES The following review guidelines were devel0ped after initial evaluation of the various utility r~sponses to Item 1.2 of Generic Letter 83-28 and incorporate the best features of these suhmittals.
As such, thesP. review guidelines in,
effer:t represent a "~wad practices" approach to post-trip review.
We have re.::
viewed the licens~e's response to Item 1.2 against these guidelines:
A.
Th~ equipment that provides the diqital sequence of events (SOE) record and the analog time history records of an unscheduled shutdown should provide a reliable source of the necessar.v information to be used in the post-trip review.
Each plant variable which is necessary to determine the cause and progression 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 strip charts, a plant process computer or analog recorder for analog (time history) variables *. Performance characteristics guidelines for SOE and time history recorders are as follows:
- o Each sequence of events recorder should be capable of detecting and recording the sequence 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 FSAR Chapter1.4i. Accident Analyses.
The recommended.guidelines for the SOE time discrimination is approximately 100 milliseconds. If current SOE recorders do not 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 and post-trip events.
As a minimum, this should include the ability to adequately reconstruct the transient an accident scenarios presented in Chapter 14 of the plant FSAR.
o Each analog time history data recorder should have a sample 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
- e analysis of Chapter 15 of.the plant FSAR.
The recommended guideline for the sample interval is 10 seconds. If the time history equipm~nt does not meet this guideline, the licensee should show that the time history capability is sufficient to accurately reconstruct the transiP.nt and accident sequences presented in Chapter 14 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 recorder should be capable of updating and retaining information from approximately 5 minutes prior to the trip until at least
- 10 minutes after the trip.
o All equipment used to record sequence of events and time history information should be powered from a reliable and non-interruptable power source.
The power source used need not be Class lE.
B.
The sequence of events and time history recording equipment should monitor sufficient digital and analog parameters, respectively, to assure that the course of the reactor trip and post-trip events can be reconstructed.
The parameters monitored should provide sufficient infonnation to determine the root cause of the unscheduled shutdown, the progression of the reactor trip, and the response of the plant parameters and protection and safety systems to the unscheduled shutdowns.
Specifically, all input parameters
\\ associated with reactor trips, safety injections and other safety-related systems as well as output parameters sufficient to record the proper functioning of these systems should be recorded for use in the post-trip revie1-1.
The parameters deemed necessary, as a minimum, to perform a post-trip review that would determine if th~ plant remained within its safety limit design envelope are presented in Table, 1.
They were selected on the bas\\s of staff engineering judgment following a complete evaluation of utilit_y submittals.
If the licensee's SOE recorders and time history recorders do not monitor all of the parameters suggested in these tables, the licensee should show that the existirig set of monitored parameters is sufficient to establish that the plant remained within the design envelope
- for the accident conditions analyzed in Chapter 14 of the plant FSAR.
C.
The information gathered b.v the sequence of events and time history recorders should be stored in a manner that will allow for data retrieval and analysis.
The data ma.v be retained in either hardcop.v, (e.g., com-puter printout, strip chart record), or in an accessible memo~y (e.g.,
magnetic disc or tape).
This information should be presented in a read-able and meaningful format, taking into consideration good human factors practices such as those outlined in NUREG-0700.
D.
Retention of data from all unscheduled shutdowns provides a valuable reference source for the determination of the acceptability of the plant vital parameter and equipment response to subsequent unscheduled shutdowns.
Information gathered during the post-trip review is to be retained for the life of the plant for post-trip review comparisons of subsequent events.
III. EVALUATION AND CONCULSION By letters dated July 1, 1985 and May 5, 1986, the Consumers Power Company provided information regarding its post-trip review program data and information capabilities for Palisades Nuclear Plant. The staff has evaluated the licensee's submittals against the review guidelines described i~ Section II. A deviation from the Guidelines of Section II regarding control rod position recording was addressed by NRC letter to Mr. Kenneth Berry dated April 1, 1986. A brief description of the licensee's respo~ses and the staff's evaluation of the response against each of the review guidelines follows:
A.
The licensee has described the performance characteristics of the equipment used to record the sequence of events and time history data needed for post-trip review.
Based on the staff's review of the licensee's submittals, it finds that the data logger, critical functions monitor and time history recording capability conform to the guidelines described in Section II A, and are acceptable.
B.
The license has established and identified the parameters to be monitored and recorded for post-trip review.
By letter dated May 5, 1986, the licensee committed to upgrade the data collection of control rod pGsitions following a trip by the end of the 1987 refueling outage.
With the implementation of this commitment, 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 II B and, therefore, are acceptable.
C.
The licensee-described the means for storage and retrieval of the information gathered by the datalogger, the critical functions monitor and time history recorders, and for the presentation of this information for post-trip review and analysis. Based on the staff 1 s review, it finds that this information wi 11 be presented in a readable and meaningful format, and that the storage, retrieval and presentation conform to the guidelines of Section II C.
D.
The licensee indicates that the data and information used during post-trip reviews is being retained in an accessible manner for the life of the plant. Based on this information, the staff finds that the licensee's program for data retention conforms to the guidelines of Section II.D, and is acceptable.
Ba~ed on the staff's review of the licensee's submittals, it concludes that the licensee's post-trip review and data and information capabilities for Palisades Nuclear Plant are acceptable.
Principal Contributors:
J. Kramer T. Wambach
8 -
TABLE 1 PWR PARAMETER LIST SOE Time History Recorder Recorder Parameter/Signal
{l) x Reactor Trip (1) x Safety Injection x
Containment Isolation (l) x Turbine Trip x
Control Rod Positio,n (l) x x
Neutron Flux, Power x
x Containment Pressure (2)
Containment Radiation x
Containment Sump level (l) x x
Primary System Pressure (1) x x
Primary System Temperature (1) x Pressurizer Level (l) x Reactor Coolant Pump Status (l) x x
Primary System Flow
( 3)
Safety Inj.; Flow, Pump/V~lve Status
. x MSIV Position x
x Steam Generator Pressure (1) x x
Steam Generator Level (1) x x
Feedwater Fl ow (l) x x
Steam Flow
i I
I I 1
. ; I I I I
- i*.
a 9 -
sor:
Recorder lime History Recorder Parameter/Sign2l (J)
(2)
(3)
(3)
Auxiliary Feedwater System: Flow.
x x
x Pump/Valve Status AC and DC Systelil Status (Bus Voltage)
Diesel Generator Status (Start/Stop, On/Off)
PORV Position Trip paralileters Paralileter may be monitored by either an SOE or time history recorder.
Acceptable recorder options are:: (a) system flow recorded on an SOE recorder; (b) system flow recorded on a time history recorder; or (c) equipment status recorded on an SOE recorder.