ML20215D308

Proposed Tech Specs Clarifying Difference in Air Flow Rate Through Reactor Bldg Purge Valves W/ or W/O Containment Integrity

ML20215D308
Person / Time
Site:	Rancho Seco
Issue date:	12/12/1986
From:	SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:
Shared Package
ML20215D293	List: ML20215D291 ML20215D308
References
NUDOCS 8612160313
Download: ML20215D308 (2)

Text

RANCHO SECO UNIT 1

, TECHNICAL SPECIFICATONS Surveillance Standards 4.11 REACTORBUILDING'PURGEEXHAllSTFILTERINGSYSTEM Applicability Applies to the Reactor Building Purge Exhaust filter system.

Objective To verify that the Reactor Building purge exhaust filter system and its components will be able to perform their design functions.

Specification 4.11.1 Proper operation of this exhaust ventilation system shall be:

129>< A. Verified at a CONTAINMENT INTEGRITY condition within 30 days prior to start of fuel handling in the Reactor Building, by observing flow through the HEPA filter and charcoal adsorber train and verifying that the train operates with at least two, but less than six, inches water gauge pressure drop across the combined HEPA and 129> Charcoal filter banks. Air flow rate through the filter train during the observation shall be adjusted to maintain 60,000 cfm

• 10%, which is the maximum achievable flow rate at the condition of

< CONTAINMENT INTEGRITY.

B. Verified at least once per refueling interval, or once every 18 months, whichever occurs first, or after each partial or complete replacement of the HEPA filter bank or charcoal adsorber bank, or following painting, fire, or chemical release in the operating air makeup system, or after any structural maintenance on the HEPA filter or charcoal adsorber housings, by:

1. Verifying that the charcoal adsorbers remove >99.5 % of a halogenated hydrocarbon refrigerant test gas when they are tested in-place in accordance with ANSI N510 while operating the filter train at a flow rate of 66,700 cfm

• 10% .

2. Verifying that the HEPA filter banks removed >99.9 % of the DOP when they are tested in-place in accordance with ANSI N510 while operating the filter train at a flow rate of l 66,700 cfm

• 10% .

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3. Verifying within 31 days after removal, that a lab analysis of a carbon sample from at least one test canister or carbon sample renoved from one of the charcoal adsorbers demonstrates a removal efficiency of >95 % for radioactive methyl iodide when the sample is tested as used charcoal in accordance with ASTM D3803 (30*C, 95% R.H.). The carbon samples not obtained from test canisters shall be prepared from either:

Proposed Amendment No. 129 4-42 8612160313 861212 PDR ADOCK 05000312 P PDR

• RANCHO SECO UNIT 1

- TECHNICAL SPECIFICATONS Surveillance Standards Specification (Continued) 129> 4.11.10.2 (b) Verify that the HEPA filter banks remove >99.9 % of the DOP when they are tested in-place in accordanie with ANSI N510 while operating the filter train at a flow rate of

< 66,700 cfm

• 10%.

Bases The Reactor Building Purge Exhaust filter system consists of prefilter, HEPA tilter, and Type II Charcoal Filter Banks arranged in series. Provisions are made to ventilate the building at two basic rates: 16,670 cfm in " Winter" and 129> 66,700 cfm in " Summer," except during CONTAINMENT INTEGRITY conditions, the maximum air flow rate is 60,000 cfm

• 10% . There is no restriction as to which is used, other than during containment integrity conditions. During normal operation, the Reactor Building Purge Valves are closed per Specification 3.6.7; thus, there is then no flow through the Reactor Building

< Purge Exhaust filter system through the purge valves. Dampers are provided downstream of the filter train which allow outside ambient air to be drawn into the fan such that it operates at a constant 74,000 cfm. The fan discharge is routed, via two ducts, to vent to atmosphere near the top of the Reactor Building.

The Reactor Building Equalizing line allows relieving excess building pressure accumulated during operation to be vented into the purge exhaust filters, even if the fan is shutdown. This ensures that the relatively small volume of vented gas will be filtered prior to dispersion.

The purpose of the filter train is to assure as low as reasonably achievable doses would result from a dropped fuel assembly, or if a LOCA were to occur during purging.

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i Proposed Amendment No. 129 4-42b I

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