Information Notice 1990-19, Potential Loss of Effective Volume for Containment Recirculation Spray at PWR Facilities

Potential Loss of Effective Volume for Containment Recirculation Spray at PWR Facilities
	ML031130259
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 03000306, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	03/14/1990
From:	Rossi C; Office of Nuclear Reactor Regulation
To:	;
References
	IN-90-019, NUDOCS 9003080213
	Download: ML031130259 (8)
	v • d • e

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UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 March 14, 1990

NRC INFORMATION NOTICE NO. 90-19: POTENTIAL LOSS OF EFFECTIVE VOLUME FOR

CONTAINMENT RECIRCULATION SPRAY AT

PWR FACILITIES

Addressees

All holders of operating licenses or construction permits for pressurized water

1 reactors (PWRs).

Purpose

This information notice is intended to alert addressees to the possible loss of

effective volume for containment recirculation spray caused by the entrapment

of water in the refueling canal of PWRs. It is expected that recipients will

review the information for applicability to their facilities and consider

actions, as appropriate, to avoid similar problems. However, suggestions

contained in this information notice do not constitute NRC requirements;

therefore, no specific action or written response is required. This infor- mation notice resolves and completes action on Generic Safety Issue 95,

Loss of Effective Volume for Containment Recirculation Spray."

Description of Circumstances

In 1983, the NRC staff resident inspector at H. B. Robinson Unit 2 questioned

the licensee's practice of leaving the refueling canal drain valve in the

closed position during plant operation. The specific concern was that if

the refueling canal drain valve tina PWR dry containment Is closed during

plant operation and the plant experiences a loss-of-coolant accident (LOCA),

that fraction of the containment spray which falls into the refueling canal

would be prevented from returning to the containment emergency sump. Eventu- ally the entire volume of the refueling canal could be filled with water, preventing that amount of water from being available for the post-LOCA re- circulation mode for containment and reactor cooling.

A subsequent investigation by the H. B. Robinson licensee revealed that

Westinghouse had intended the refueling canal drain valve to be open during

operation. However, operation with the valve closed was found to have

negligible safety significance because the maximum volume of water that

could be entrapped in the refueling canal was small relative to the large

volume of water available from the refueling water storage tank. Never- theless, the licensee decided to operate the plant with the valve open

and revise plant procedures accordingly.

9003080213 b

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IN 90-19 March 14, 1990 The staff reviewed the licensee's response and corrective action (operation

with the drain valve open) and found them acceptable. Further, the staff

considered the potential generic implications of this issue. Of particular

concern was whether there are large spaces that might entrap the recirculation

water and whether this water can be adequately drained to the containment sump.

The staff addresses this concern in the design review under Standard Review

Plan (SRP) Section 6.2.2, 'Containment Heat Removal System." However, there

are PWR plants that were not reviewed under SRP Section 6.2.2 to determine if

the entrapment of containment recirculation water could occur. There are 27 PWR plants licensed before SRP Section 6.2.2 was issued. Other PWR plants were

reviewed under SRP Section 6.2.2, but plant procedures may not have been ex- plicitly evaluated for this safety matter.

Safety Significance:

The principal concern is the potential for the entrapment of containment spray

water in operating PWRs. The concern arises because if a sufficient volume of

spray water is prevented from returning to the containment emergency sump, adequate flow in the containment spray recirculation and emergency core coolant

recirculation mode may not be provided. Insufficient flow to the sump can

result in inadequate net positive suction head to the containment spray and

low pressure safety injection pumps. Subsequently, proper post-LOCA contain- ment cooling and reactor core cooling can be disabled.

In the NRC staff's evaluation of Generic Safety Issue 95, the staff concluded

that the safety significance of this issue depends primarily upon whether en- trapment of an unacceptable volume of containment spray water could occur during

the recirculation phase. Licensees may wish to review the adequacy of their

procedures for ensuring proper water drainage to the containment emergency sump.

Requiring that the refueling canal drain valves be open while the reactor is

operating or other comparable provisions may be appropriate. In this con- nection, we note that the current plant technical specifications for PWRs

with ice-condenser containments include operability and surveillance require- ments for the refueling canal drain valve during power operation.

This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact the

technical contact listed below or the appropriate NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contact:

Chang-Yang Li, NRR

(301) 492-0875 Attachment: List of Recently Issued NRC Information Notices

.,, I i

Attachment

IN 90-19 March 14, 1990 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date ot

Notice No. Subject - Issuance Issued-to

90-18 Potential Problems with 3/9/90 All holders of OLs

Crosby Safety Relief Valves or CPs for nuclear

Used on Diesel Generator power reactors.

Air Start Receiver Tanks

90-17 Weight and Center of 3/8/90 All holders of OLs

Gravity Discrepancies or CPs for nuclear

for Copes-Vulcan Valves power reactors.

89-59, . . Suppliers of Potentially 3/7/90 All holders of OLs

Supp. 2 Misrepresented Fasteners or CPs for nuclear

power reactors.

90-16 Compliance with New 3/7/90 All materials licensees.

Decommissioning Rule

90-15 Reciprocity: Notification 3/7/90 All holders of NRC

of Agreement State Radiation materials licenses _._

Control Directors Be ore which authorize use

Beginning Work in Agreement of radioactive

States material at temporary, Job sites.

90-14 Accidental Disposal of 3/6/90 All U.S. NRC byproduct

Radioactive Materials material licensees.

90-13 Importance of Review and 3/5/90 All holders of OLs

Analysis of Safeguards or CPs for nuclear

Event Logs power reactors.

90-12^ Monitoring or Interruption 2/28/90 All holders of OLs

of Plant Communications or CPs for nuclear

power reactors.

90-11 Maintenance Deficiency 2/28/90 All holders of OLs

Associated with Solenoid- or CPs for nuclear

Operated Valves power reactors.

90-10 Primary Water Stress 2/23/90 All holders of OLs

Corrosion Cracking (PWSCC) or CPs for PWRs.

of Inconel 600

OL = Operating License

CP = Construction Permit

~ IN 90-19 March 14, 1990 The staff reviewed the licensee's response and corrective action (operation

with the drain valve open) and found them acceptable. Further, the staff

considered the potential generic implications of this issue. Of particular

concern was whether there are large spaces that might entrap the recirculation

water and whether this water can be adequately drained to the containment sump.

The staff addresses this concern in the design review under Standard Review

Plan (SRP) Section 6.2.2, *Containment Heat Removal System." However, there