ML20236Y336

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Safety Evaluation Supporting Util 831107 Response to Generic Ltr 83-28,Item 1.2 on post-trip Review & Data & Info Capability
ML20236Y336
Person / Time
Site: Pilgrim
Issue date: 07/10/1986
From:
NRC
To:
Shared Package
ML20149B797 List:
References
FOIA-87-644 GL-83-28, NUDOCS 8712110251
Download: ML20236Y336 (11)
v • d • e


Text

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SAFETY EVALUATION REPORT GENERIC LETTER 83-28 ITEM 1.2 - POST-TRIP REVIEW (DATA AND INFORMATION CAP /EILITY)

PILGRIM STATION DDMT NO. 50-293

1. INTRODUCTION On February 25, 1983, both of the scram circuit breakers at Unit 1 of the Salem Nuclear Power Plant (SNPP) failed to open upon an automatic reactor trip signal from the reactor protection system. This incident occurred during the plant start-up and the reactor was tripped manually by the operator about 30

, seconds after the initiation of the automatic trip signal. The failure of the circuit breakers has been determined to be related to the sticking of the undervoltage trip attachment. On February 22, 1983, during start-up of SNPP, 1

l Unit 1, 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 ATVS Events at the Salem Nuclear i

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 permits to respond to certain generic concerns. These concerris 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.

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8712110251 871209 PDR FOIA SORGIB7-644 PDR

The first action item, Post-Trip Review, consists of Action Iten 1.1, " Program Description and Procedure

  • and Action Item 1.2, " Data and Information Capability." This safety evaluation report (SER) addresses Acticn Item 1.2 only.

II. REVIEW GUIDELINES The following review guide'!ines were developed after initial evaluatinn 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 i effect represent a " good practices" approach to post-trip review. We have re-i' viewed the licensee's resp:nse to Item 1.2 against these guidelines: '

A.

The equipment that prtvides the digital sequence of events (5CE) record and the analog time history records of an unscheduled shutdown should provide a reliable source of the necessary 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 post trip should be monitored by at least one recorder (such as a sequence-of-events recorder or a plant process com: uter) for digital ~ parameters; and strip : harts, a plant process computer or analog recorder for analog (tine history) j variables. Performance characteristics guidelines for SOE ard time l

history recorders are as follows:

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o Each sequence of events recorder should be cepable 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 l

ascertained, and that a determination can be made as to whether the time response is within acceptable limits based on FSAR Chapter 15 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 and accident scenarios presented in Chapter 15 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 acciaent sequences evaluated in the accident I

l analysis of Chapter 15 of the plant FSAR. The re:omnended guideline for the semple interval is 10 seconds. If the time history equipment does not meet this guideline, the licensee should show that the time history capability is sufficient to l

accurately reconstruct the transient and accident sequences 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 history data recorder should be capable of updating and retaining infonnation from approximately five minutes prior to the trip until at least ten minutes after the trip.

o All equipment used to record sequence of events ar: time history infonnation should be powered from a reliable and con-interruptible power source. The power source used need not be Class 1E. l B.

The sequence ~ of events and time history recording equipnent 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 information to determine the root cause of the unscheduled shutdown, the progression of the reactor trip, and t'ne response of the plant parameters and prote: tion and safety systems to the unscheduled shutdowns. Specifically, all input parameters

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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 review. The parameters deemed necessary, as a minimum, to perform a post-trip review that would vetemine if the plant remained within its safety limit design envelope are presented in Table 1. They were selected on the basis of staff engineering judgment following a complete evaluatiom of utility 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 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.

C.

The infomation gathered by the secuence of events and time history recorders should be stored in a manner that will allow for data retrieval and analysis. The data may be retained in either hardcopy (e.g., com-puter printout, strip chart record), or in an accessible memory (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.

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1 D. Retention of data from all unscheduled shutdowns provides a valuable j i

reference source for the determination of the acceptability of the plant j

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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 CONCLUSION By letter dated November 7,1983, the Boston Edison Company provided information regarding its post-trip review program data and infonnation capabilities for I

Pilgrim Statson. We have evaluated the licensee's submittal against the review guidelines described in Section II. Deviations from the guidelines of Section II were discussed with representatives of the licensee by telephone on February 12 and 26, 1986. A brief description of the licensee's responses and the staff's evaluation of the responses against each of the review guidelines follows:

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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 our review of the licensee's I I

submittal and the information provided by the licensee during the above j

i telecons, we find that the sequence of events recorder and time history I i recorder characteristics conform to the guidelines described in Section

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II A, and are acceptable. I l

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B. The licensee has established and identified the parameters to be monitored and recorded for post-trip review. Based on our review, we find that the parameters selected by the licensee include all but ene of those identified in Table 1. While Diesel Generator Status is tot included as a parameter, there are indicators in the control room that provide this information. The staff finds this acceptable. Con- {

sequently, we find that the licensee's selection of parameters meets the intent of the guidelines described in Section II.B and is, there- ,

fore, acceptable.

C. The licensee described the means for storage and retrieval of the information gathered by the sequence of events and time history recorders, and for the presentation of this information for post-trip review and analysis. Based on our review, we find that this information j will be presented in a readable and meaningful format, and that the storage, retrieval and presentation conform to the guidelines of i Section II C. I D. During the February 26, 1986 telecon, the licensee stated that the data and information used during post-trip reviews are being retained in an accessible manner for the life of the plant. Based on this information, we find that the licensee's program for data retention conforms to the l 1

guidelines of Section II D, and is acceptable. j l

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Based on our review of the applicant's submittal and the telecons with the licensee, we conclude that the licensee's post-trip review data and informa- l tion capabilities for Pilgrim Station are acceptable.

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r TABLE 1 BWR PARAMETER LIST

e. s .

SOE Time History Recorder Recorder Parameter / Signal x Reactor Trip c .

x Safety Injection

! x Containment Isolation x Turbine Trip

-x Control Rod Position x(1) x Neutron Flux, Power x (1) Main Steam Radiation (2) Containment (Dry Well) Radiation x (1) x Drywell Pressure (Containment Pressure)

(2) Suppression Pool Temperature

, x(1) x Primary Syitem Pressure x (1) x Primary System Level x MSIV Position x(1) Turbine Stop Valve / Control Valve Position 1

x Turbine Bypass Valve Positior x Feedwater Flow x Steam Flow (3) Recirculation; Flow Pump }tatus '

x (1) Scram Discharge Level-X (1) Condenser Vacuum

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l 1

SOE Time History Recorder Recorder Parameter / Signal x -

AC and DC System Status (Bus Voltage)

(3)(4) Safety Injection; Flow. Pump / Valve Status x ,

Diesel Generator Status (on/Off, Start /Stop) l (1) Trip parameters (2) Parameter may be recorded by either an SOE or time h,istory recorder.

(3) 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.

(4) Includes recording of parameters for all applicable syst3ms from the e

following: HPCI, LPCI, LPCS, IC, RCIC.

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4 ENCLOSURE 2 SALP EVALUATION PILGRIM STATION DOCKET NO. 50-293-GENERIC LETTER 83-28, ITEM 1.2, POST-TRIP REVIEW A. Functional A:eas: Licensing (Ativities - Generic Letter E3-28.

Item 1.2. Post-Trip Review Data and. Information Capability

1. Management involvement in assuring quality.

Based on our review of the licensee's response to Generic Letter 83-1, we find that the licensee has an effective capability for the collection, storage and retrieval of data needed to assess unscheduled reactor trips.

Rating: Category 2.

2. Approach to resolution of technical issues from a safety standpoint.

Rating: N/A

3. Responsive to NRC initiatives.

Based on our review, we find that the licensee is responsive to NRC initiatives.

Rating: Category 2.

4. Staffing:

Rating: N/A

5. Reporting and analysis of reportable events Rating: N/A
6. Training and qualification effectiveness l Rating: N/A
7. Overall Rating for Licensing Activity Functional Areas:

Category 2.

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