IR 05000312/1988011

Insp Rept 50-312/88-11 on 880317.No Violations Noted.Major Areas Inspected:Unusual Event on 880315

ML20153C248
Person / Time
Site:	Rancho Seco
Issue date:	04/20/1988
From:	Fish R, Prendergast K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
Shared Package
ML20153C247	List: IR 05000312/1988011 ML20153C245
References
50-312-88-11, NUDOCS 8805060192
Download: ML20153C248 (3)

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U. S. NUCLEAR REGULATORY COMPilSSION

' REGION V Report No. 50-312/88-11 Docket No. 50-312 License No. DPR-54-

-Licensee: Sacramento Municipal Utility District 14440 Twin Cities Road-Herald, California 95638-9799 Facility Name: Rancho Seco Nuclear Generating Station Inspection at: Clay Station, California Inspection Conducted: March 17, 1988 Inspectors: t A M 20 [

Kent M.'Prendergast Dat4 Sfgned Emergency Preparedness Analyst Approved by:

,_ Fish, Chief M k[

Ddte signed Emetgency Preparedness Section Summary:

Inspection on March 17, 1988 (Report No. 50-312/88-11)

Areas Inspected: Routine unannounced inspection of an unusual event on March 15, 198 Inspection Procedure 93702 was covere Results: No violations of NRC requirements were identifie PDR ADOCK 05000312 O DCD

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DETAILS 1. Persons Contacted S. Redeker, Deputy Operations Manager P. Lavely, Manager, Environmental Protection

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M. Hammons, Emergency Preparedness Specialist J. Price, Emergency Preparedness Specialist H. Story, Supervisor, Health Physics and Chemistry Services 2. Follow-up On Non Routine Events at Power Reactors (93702)

This was a special inspection of an event occurring on March 15, 1988. At 2230 Pacific Standard Time (PST), with the reactor in hot shutdown at normal operating temperature and pressure, a leak in the letdown system occurre The leak was terminated in about six minutes and resulted in approximately 650 gallons of reacter coolant being

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deposited in the containment sum The licensee declared an "Unusual l

Event" based on the unidentified reactor coolant leakage rate exceeding 1 gallon per minute (technical specification limit) as required by Tab 11 of EPIP 5001. Notifications to the State of California and local l

(county) agencies regarding the unusual event were made at 2257 PS The licensee terminated the event at 2317 PST and notified the State and counties of the termination at 2321 PST. At about the time of the event

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termination notification, the licensee developed information that showed j the leakage rate was cpproximately 91 gallons per minute (gpm).

I According to Tab 11 of EPIP 5001, the 91 gpm leak rate should have been classified as an "Alert" even The licensee said that they discussed the matter of event classification, but decided the situation did not warrant mentioning the "Alert" classification to the offsite agencies.

l The basis for this decision was the event did not involve an actual or potential degradation of the level of safety of the plant (alert description) and the leak had already been terminate The NRC was notified of the event at 2322 PS Based upon this inspection it appears that the licensee acted quickly and responsibly to identify the source and terminate the leak. The classification of the event was timely and the necessary notifications were mad Based upon this inspection, the following items were noted to require further attention by the license . The classification procedure and the Emergency Plan were both noted to contain one example of an incorrect condition for an aler Both documents contained wording for an alert to be declared if reactor coolant leakage rate exceeds makeup pump capacity. This is clearly a more serious condition and should be classified as a site area l emergenc The classification procedure and the Emergency Plan need to be examined to insure any additional errors are eliminated and that the design basis for the initiating condition of any emergency classification is conservativ The changes made to the classification procedure and related section of the emergency plan will be examined during a subsequent inspection (0 pen Item 88-11-01).

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,. There were some problems in the operation of the IDADs system during the event and in the subsequent attempt to retrieve event dat This item will be followed in a subsequent inspection (0 pen Item 88-11-02).

No violations of NRC requirements were identified during this inspectio . Exit Interview An exit interview to discuss the preliminary NRC findings was held on March 17, 1988'with Mr. Harvey Stor The licensee was informed there were no violations identified within the scope of this inspectio In addition, the findings contained in Section 2 of this report were also summarized in a meeting with Mr. Paul Lavely and other members of licensee staff on March 18, 198 .