Event Notification Report for September 18, 2001

LOSS OF DOUBLE CONTINGENCY.

NRC BULLETIN 91-01 4 HOUR NOTIFICATION

At 1404 during facility stand down recovery efforts, a wall penetration for conduit lines above the A-loop concentrate slab was questioned as a possible violation on NCSA-0705_076, Inadvertent Containers. The concrete blocks used in the construction of the wall have internal void spaces which could accumulate an unsafe amount of material in the event of a spill or leak. The edges of the penetration were not sealed or covered to prevent solution from entering. If the feed pump for the A-loop concentrate slab were operating (X-705 operations are currently in stand-down mode), solution could potentially spray onto the conduit and run into the openings. The feed pump will remain administratively tagged out of service until the potential spray path is mitigated. Repairs are in progress.

Following identification of the above event, a walkdown was conducted in all inadvertent Container Areas to locate any similar problems. Numerous cracks, holes, and penetrations were identified in the block walls of the Recovery Area. Small cracks and joints in the walls are not considered a violation of the NCSA controls because it is not credible that an unsafe amount of material could seep through a crack in a (vertical) wall and collect in an unsafe geometry. However, many holes were observed that could potentially collect an NCS significant amount of material if a spray or leak stream were to be aimed directly at the hole. This is a violation of the administrative controls of NCSA-0705_076 for Inadvertent Containers. Due to the number of penetrations/holes identified by subsequent walkdowns of the Recovery Area, compliance with NCSA controls could not be reestablished within 4 hours. Thus making this event a criticality control 4-hour 91-01 bulletin event.

The safety significance is low because there was no leak of uranium bearing material near the identified openings in the walls of the Recovery Area.

A walkdown of the Microfiltration Area and Tunnel Basement Area (also subject to Inadvertent Container controls) did not find any violations of NCS controls.

SAFETY SIGNIFICANCE OF EVENTS:

The safety significance is low because there was no leak of uranium bearing material near the identified openings in the walls of the Recovery Area. The area in question is designated an "Inadvertent Container Area" due to the presence of the Recovery System, which is not currently in operation due to a stand down of all X-705 operations. The presence of an inadvertent container in the are is a violation of NCS controls and one leg of the double contingency principle as described in NCSE-705_076.E03.

POTENTIAL CRITICALITY PATHWAYS INVOLVED (BRIEF SCENARIO(s) OF HOW CRITICALITY COULD OCCUR):

For a criticality to occur, the following events would be required: The recovery system would have to be operating and processing uranium bearing liquid with a high concentration of uranium. Then a leak in the system must occur such that an unsafe amount of liquid sprays from the system directly into one of the identified openings in the block wall. The liquid would then have to flow through the small opening and collect in the internal void spaces of the block wall forming an unsafe geometry. Depending on the volume collected, some reflection would also be required to sustain a critical chain reaction. The Recovery System is not currently an operation, and will remain shutdown until the holes/penetrations are mitigated.

CONTROLLED PARAMETERS (MASS, MODERATION, GEOMETRY, CONCENTRATION, ETC.):

Inadvertent containers are controlled based upon volume (2.5 liters maximum) or geometry (1.5 inches in depth or 4 inches in diameter). The exact potential collection volume inside the block wall is unknown. Although analyzed for 100% enriched materials. The Recovery System would currently process material with less than or equal to 5% enrichment.

ESTIMATED AMOUNT, ENRICHMENT, FORM OF LICENSED MATERIAL (INCLUDE PROCESS LIMIT AND % WORST CASE OF CRITICAL MASS):

No uranium bearing material was involved in this event. There was no leaks of uranium bearing material in the area while the opening in the walls were present. The event involves the presence of an unsafe geometry (the inside of the block wall) that could collect solution in the event of a spill.

NUCLEAR CRITICALITY SAFETY CONTROL(s) OR CONTROL SYSTEM(s) AND DESCRIPTION OF THE FAILURES OR DEFICIENCIES

The presence of holes in the block walls could lead to the collection of a spill or leak on the unfavorable geometry void spaces. This is a violation of control # 3 of NCSA-0705_076, Inadvertent Containers, which specifically evaluates this event. Note that it was not possible to mitigate all of the holes in the Recovery Area walls; therefore, Recovery operations remain shutdown until expedited repairs can be completed.

CORRECTIVE ACTIONS TO RESTORE SAFETY SYSTEM AND WHEN EACH WAS IMPLEMENTED:

Feed pump for the A-loop concentration slab will remain tagged out of service until the potential path is mitigated.

The NRC Resident Inspector was notified of this event.

LOCAL LEAK RATE TESTING (LLRT) OF MAIN STEAM ISOLATION VALVE (MSIV) "2B" LIMITS EXCEEDED.

During LLRT of MSIV's per appendix J of 10CFR50 the "2B" 21F022A and "2B" 21F028A were found to be leaking 192 scfh (standard cubic feet per hour); diagnostic testing determined that "2B" 21F022A is leaking at approximately 130 scfh. (Technical Specification Surveillance requirement limit is 100 scfh). The "2B" 21F022B was found to be leaking above 100 scfh and above the maximum pathway allowable leakage of 250 scfh for all four lines.

The NRC Resident Inspector will be notified of this event by the licensee.

* * * RETRACTION 2203 10/18/2001 FROM WATTS TAKEN BY STRANSKY * * *

"On 9/18/01 at 15:13 EDT Plant Hatch made a Notification of Significant Event Report number 01-12 to the NRC (Mr. MacKinnon). The 50.72(b)(3)(ii)(A) report was made for failure of the MSIVs to pass Local Leak Rate Testing (LLRT). The initial test of the penetration 2B21F022A and penetration 2B21F022B leaked greater than the Technical Specification Surveillance Requirement 3.6.1.3.11 of 100 SCFH. Also, the leakage through the 2B21F022B was sufficient to be greater than the same Technical Specification Surveillance Requirement 3.6.1.3.11 of 250 SCFH for all four Main Steam lines. At the time of this notification the actual as found leakage through each penetration pathway could not be determined because the test is conducted between the valves in each penetration.

"Per the Event Report Guidelines in NUREG-1022, the containment leak tests where the total containment as found, minimum-pathway leak rate exceeds the LCO in the facilities Technical Specifications would be reportable. The minimum-pathway leak rate means the minimum leak rate that can be attributed to a penetration leakage path. The NUREG-1022 explains for example, the smaller of either the inboard or outboard valve's individual leak rates. Therefore, after repairing the 2B21F022B and the 2B21F028A and before the repair of the other valves (one inboard and one outboard) another LLRT was performed for each penetration pathway. These LLRT results showed that the minimum-pathway leak rate did not exceed the Technical Specification Surveillance Requirement 3.6.1.3.11 of 100 SCFH for either penetration pathway. Also, the minimum-pathway leak rate for all four Main Steam lines did not exceed the Technical Specification Surveillance Requirement 3.6.1.3.11 of 250 SCFH."

The NRC resident inspector has been informed of this retraction. Notified R2 IRC.