Event Notification Report for May 08, 2012

IMPROPERLY ANALYZED CONDITION

"This plant condition is being reported under 10CFR70, Appendix A criterion (b)(1), 'Any event or condition that results in the facility being in a state that ... was improperly analyzed ... and which results in a failure to meet the performance requirements of 10CFR70.61.'

"AREVA's conclusion that such a condition exists at the AREVA Richland facility is based on an NRC issued letter dated May 7, 2012 from John D. Kinneman to Janet R. Schlueter which among other things states:

"'It is not acceptable, however, to conclude that a process does not need IROFS because an event is 'not credible' due to the characteristic provided by some other controls or features of the plant that are not IROFS.'

"Based on this NRC position, AREVA did not adequately analyze the facility (in accordance with the May 7th position) because unacceptable consequences resulting from some process upsets were determined to be 'not credible' based on plant conditions or features that were not declared as IROFS.

"For example, an accidental criticality accident resulting from a solution leak onto the floor was declared not credible because gravity would cause the leak to spread out on the floor into a safe geometry. However, the floor was not declared an IROFS. Another example is that accidental criticality in a 1-inch diameter pipe was declared 'not credible' due to the geometry of the pipe and no credible mechanism being identified that could cause the pipe to balloon into an unfavorable geometry, yet the pipe diameter was not declared an IROFS. Other similar conditions exist at the Richland facility.

"Therefore, AREVA Richland has concluded that the NRC approved ISA does not meet the performance requirements of 10CFR70.61(e). However, the safety significance of this technical non-compliance is considered to be low because all proposed changes to the facility are evaluated for potential impact to the facility ISA before they are made. These changes are reviewed and approved by a diverse group of people including staff who is familiar with the safety basis for each process system and the 10CFR70.72 change control requirements and will not authorize changes that could invalidate the safety basis.

"Additionally, although these items are not individually identified as IROFS, the ISA summary on pg. 7-9 states:

"'... the following general criticality safety program elements are considered IROFS, albeit that they differ from other listed IROFS in that although they are key to safety, they are not always individually identified and used in specific accident sequences:

"-- equipment dimensions and materials forming the basis for a nuclear criticality safety analysis (NCSA); and

"-- bounding assumptions used in an NCSA'."

AN UNANALYZED CONDITION COULD DELAY TRANSFER TO EMERGENCY DIESEL GENERATORS UNDER CERTAIN POSTULATED CONDITIONS

"At 0900 [CDT] on May 8, 2012, it was determined that Monticello Nuclear Generating Plant did not meet Technical Specification Limiting Condition for Operation 3.3.8.1 because the requirement of Table 3.3.8.1-1 for the 4.16 KV Essential Bus Degraded Voltage time delay transfer to the Emergency Diesel Generators [EDGs] of 9.2 seconds could not be met under all postulated conditions. The degraded transfer scheme has the ability to transfer to an intermediate offsite source (1AR) which under a degraded voltage condition, coincident with an accident, would delay the transfer to the EDGs an additional 5 seconds. Both EDGs were subsequently declared inoperable."

As an interim action 1AR transformer has been removed from service. This eliminates the unanalyzed condition, restores Technical Specification compliance, and restores both EDGs to an operable condition.

Additionally this event is being reported under criteria 10 CFR 50.72(b)(3)(v)(D) - Accident Mitigation.

The NRC Resident Inspector has been notified.

TECHNICAL SUPPORT CENTER OUT OF SERVICE

"On 5/8/2012 at 1114 EDT, maintenance informed the Control Room that a fan blade on one of the Technical Support Center (TSC) ventilation compressors had failed, causing the fan and motor to become unstable. As a result, Operations secured TSC ventilation and declared the TSC non-functional.

"The on-call Emergency Response Manager and Site Emergency Coordinator were notified and the alternate TSC remains available.

"The affected unit has been isolated and TSC ventilation re-started and declared functional as of 1900 EDT on 5/8/2012."

The license will notify the NRC Resident Inspector.

AUTOCLAVE HIGH PRESSURE ISOLATION SYSTEM FAILURE

"At 1616 CDT, on 05-08-12 the Plant Shift Superintendent (PSS) was notified that C-360 (Toll Transfer & Sampling Building) Autoclave #2 had a failure in the Autoclave High Pressure Isolation System [AHPIS]. [AHPIS] is designed to: 1) prevent a cylinder failure inside the autoclave as a result of overheating; and 2) mitigate releases to the atmosphere from releases inside the autoclave. Autoclave containment is required to be operable per TSR 2.1.3.1 while the autoclave is in TSR modes 3 (containment), 4 (autoclave closed), and 5 (autoclave heating). On 5/08/12 at 1610 CDT an operator noticed water flowing from the autoclave head to shell sealing surface on the #2 autoclave in C-360 while a cylinder was being heated (TSR mode 5 - autoclave heating). The PSS was notified of the loss of containment at 1616 CDT and the [AHPIS] was declared inoperable. The steam cycle was interrupted and the autoclave was placed in a non-applicable TSR mode at 1657 CDT. No release of UF6 occurred due to the failure of the [AHPIS].

"This event is reportable as a 24 hour event in accordance with 10CFR 76.120(c)(2)(i). This is an event in which equipment is disabled or fails to function as designed when: a.) the equipment is required by a TSR to prevent releases, prevent exposures to radiation and radioactive materials exceeding specified limits, mitigate the consequences of an accident, or restore this facility to a pre-established safe condition after an accident; b.) the equipment is required by a TSR to be available and operable and either should have been operating or should have operated on demand; and c.) no redundant equipment is available and operable to perform the required safety function.

"The NRC Senior Resident Inspector has been notified of this event.

"PGDP Assessment and Tracking Report No. ATRC-12-1195; PGDP Event Report No. PAD-2012-02; Responsible Division: Operations"


* * * UPDATE FROM BILLY WALLACE TO DONALD NORWOOD AT 1640 EDT ON 5/9/2012 * * *

After further review the licensee determined that additional reportability criteria were met as described below:

"At 1616 on 05/08/2012, the PSS was notified that C-360 Autoclave #2 had water flowing from the autoclave head to shell sealing surface indicating a potential failure in the Autoclave High Pressure Isolation System (AHPIS) containment, which is relied on as an engineered control in NCSE 042 (SRI 5.5.3). The AHPIS is designed to minimize leaks to atmosphere from the autoclave under maximum pressures resulting from a UF6 release from the cylinder, valve or pigtail in the autoclave. The maximum acceptable leak rate for the autoclaves is 12 SCFM at a minimum test pressure of 90 psig or a 10 psi pressure drop in 1 hour. In order to determine if the AHPIS would have met its safety function, a pressure decay test will be performed. However, the pressure decay test will not be performed within 24 hours of discovery. Therefore, it is conservatively assumed that the leak discovered is greater than 12 SCFM or greater than 10 psi pressure drop in 1 hour; resulting in a 24 hour NCS reportable event. When the leak was noticed, the heat cycle was interrupted and the autoclave placed in a safe configuration. No release of UF6 had occurred in the autoclave when the leak out the autoclave was found.

"This event is reportable as a 24 hour event in accordance with 24-Hr. NRC BL 91-01 Supp. 1. This is a criticality safety event in which violations involving operations that comply with the double contingency principle and do not meet the criteria for a 4-hr report, but still result in a violation of the double contingency principle, such as, events where the double contingency principle is violated but control is immediately reestablished.

"Safety Significance of Events:
--While an NCSA control was not maintained resulting in the potential autoclave leak rate being exceeded, a release of fissile material from a cylinder in the autoclave did not occur and therefore a criticality was not possible.

"Potential Criticality Pathways Involved:
--In order for a criticality to be possible, a cylinder, valve, or pigtail of a fissile cylinder would have to fail and release greater than a safe mass of fissile material into the autoclave and the autoclave containment would have to fail allowing a large release to atmosphere of uranium and settle out in an unfavorable geometry with sufficient moderator present.

"Controlled Parameters:
--The first leg of double contingency is based on mass.

--The first leg of double contingency is based on administrative and design controls to ensure that it is unlikely to have a large release of UF6 from the cylinder, valve or pigtail in the autoclave while healing the cylinder.

--The second leg of double contingency is based on geometry moderation.

"Estimated Amount, Enrichment, Form of Licensed Material:
--No leakage of UF6 occurred.

"Nuclear Criticality Safety Control(s) or Control System(s) and Description of the Failures or Deficiencies:
--The first leg of double contingency is based on mass.

--The first leg of double contingency is based on administrative and design controls to ensure that it is unlikely to have a large release of UF6 from the cylinder, valve or pigtail in the autoclave while heating the cylinder. This control was maintained.

--The second leg of double contingency is based on geometry / moderation.

--Small leaks out of the autoclave to atmosphere are considered normal case and the Autoclave High Pressure Isolation System ensures containment to minimize a significant release to atmosphere if a release occurs in the autoclave during heating. The AHPIS ensures that the maximum leak rate from the autoclave will not exceed 12 SCFM or a maximum acceptable pressure drop of 10 psi in 1 hour. If the containment leak rate is maintained, only a small amount of uranium could leak to atmosphere and the uranium would form in thin layers on surfaces in a geometrically safe configuration. Also there would be insufficient uranium to leak outside of the building; therefore there would not be a sufficient source of moderation. Since this control is assumed to have failed, uranium could leak out of the autoclave to atmosphere if a large release of UF6 occurred in the autoclave and potentially deposit in geometrically unfavorable configurations in areas where sufficient moderators exist. Since the leak rate cannot be confirmed within 24 hours, it is conservatively assumed that the geometry moderation parameter was lost and double contingency was not maintained.

"Corrective Actions To Restore Safety Systems and When Each Was Implemented:
--Perform a pressure decay test on Autoclave #2 according to procedures and if the leak rate is determined to be greater than 12 SCFM or 10 psi in one hour, repair AHPIS prior to heating another cylinder containing uranium.

"The NRC Resident Inspector has been notified of this event.

"PGDP Assessment and Tracking Report No. ATRC-12-1195; PGDP Event Report No. PAD-2012-03; Responsible Division: Operations."

Notified R2DO (Freeman) and NMSS EO (Campbell).


* * * RETRACTION FROM DAVID PETTY TO DONG PARK AT 1403 EDT ON 5/15/2012 * * *

"Subsequent to the above notifications on May 10, 2012, autoclave no. 2 was subjected to a pressure decay test in the as-found condition. The test indicated that the High Pressure Isolation Safety System would have been capable of performing its intended safety function if called upon on May 8, 2012, during the heat cycle subject of the event reports. Thus, the event was not required to be reported under 10CFR 76.120(c)(2)(i) and the notifications may be retracted.

"Subsequent to the above notifications on May 10, 2012, autoclave no. 2 was subjected to a pressure decay test in the as-found condition. The test indicated that the High Pressure Isolation Safety System would have been capable of performing its intended safety function if called upon on May 8, 2012, during the heat cycle subject of the event reports. The pressure drop from the as-found test was less than the maximum allowable pressure drop for the system required for criticality safety. Thus, the event did not meet the criteria to be reported under 24-Hr. NRC BL 91-01 Supp. 1."

The NRC Senior Resident Inspector has been notified of this event. Notified R2DO (Shaeffer) and NMSS EO (Guttmann).

MISSING CHECK SOURCE

"On May 8, 2012, Region I identified that a survey instrument check source containing approximately 2.64 microCuries of strontium-90 was missing. The source is believed to have been inside of a metal cabinet that was inadvertently discarded on May 2, 2012, during the removal of excess property in preparation for relocation of the regional office. The source is not considered to be a hazard to public health and safety due to its low activity level and beta emission decay path. Upon discovery, the Region implemented several immediate actions including: attempts to locate and retrieve the source; confirmation that the remaining instrument check source was properly secured; and, a courtesy notification regarding this issue to the Commonwealth of Pennsylvania. In addition, a review of this event, consistent with the NRC's Management Directives, was initiated to identify and implement appropriate follow-up actions to prevent recurrence.

"This report is being submitted in accordance with NRC MD 10.131, Part V for missing material in a quantity greater than 10 times the quantity specified in 10 CFR 20 Appendix C."

THIS MATERIAL EVENT CONTAINS A "LESS THAN CAT 3" LEVEL OF RADIOACTIVE MATERIAL

Sources that are "Less than IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as moisture density gauges or thickness gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks. For additional information go to http://www-pub.iaea.org/MTCD/publications/PDF/Pub1227_web.pdf