Issue Date: 1/17/02
NRC Inspection Manual IIPB
INSPECTABLE AREA: | Operability Evaluations |
CORNERSTONE: | Mitigating Systems (90%) Barrier Integrity (10%) |
INSPECTION BASIS: | Improperly evaluated degraded and/or non-conforming
conditions may result in continued operation with a structure,
system, or component (SSC) that is not capable of performing
its design function.
This inspectable area verifies aspects of the Mitigating Systems and Barrier Integrity cornerstones for which there are no performance indicators. |
LEVEL OF EFFORT: | Review the following sample sizes of operability evaluations of degraded and non-conforming conditions which impact mitigating systems and barrier integrity: 15 to 21 per year at one reactor unit sites; 19 to 25 per year at two reactor unit sites; and 22 to 30 per year at three reactor unit sites. Although the number of required samples is an annual goal, available operability evaluation samples should be inspected each quarter to ensure a reasonable distribution throughout the year. |
01.01 | To review operability evaluations affecting mitigating systems and barrier integrity to ensure that operability is properly justified and the component or system remains available, such that no unrecognized increase in risk has occurred. |
02.01 | Operability Evaluation Review |
a. Select operability evaluations involving risk significant SSCs. Selection of operability evaluations can emerge from the inspector's review of plant status documents such as operator shift logs, emergent work documentation, and standing orders to determine if an operability evaluation is warranted for a degraded component. | |
b. Review the technical adequacy of the licensee's operability evaluation, and verify if operability is justified. Verify that the licensee considered other degraded conditions and their impact on compensatory measures for the condition being evaluated. Refer to the FSAR and other design basis documents during the review. If operability is justified, no further review is required. | |
c. If the operability evaluation involves compensatory measures, determine if the measures are in place, will work as intended, and are appropriately controlled. | |
d. If operability is not justified: | |
| |
02.02 | Identification and Resolution of Problems. Verify that the licensee is identifying problems with operability evaluations at an appropriate threshold and entering them in the corrective action program. For a sample of significant operability evaluations issues documented in the corrective action program, verify that the licensee has identified and implemented appropriate corrective actions. See Inspection Procedure 71152, "Identification and Resolution of Problems," for additional guidance. |
The licensee's process of ensuring operability is continuous and consists of the verification of operability by surveillances and continuous monitoring of plant systems. Formal determinations of operability are performed whenever a verification or other indication calls into question the SSC's ability to perform its specified function. Licensees are obligated to ensure the continued operability of SSCs as specified by TS, or to take the remedial actions addressed in the TS. The intent of this inspection is to sample licensee's operability evaluations for risk significant SSCs to verify if operability is justified, such that availability is assured, and no unrecognized increase in risk has occurred. Also, the inspections should verify that operability concerns associated with plant issues and events are being identified.
Where there is a reason to suspect that the licensee's operability determination is not, or was not correct based on the information reviewed, the inspector should discuss the issue with regional management for resolution. Depending on the complexity and risk significance of the issue, in some cases, the inspector may need to consult with regional specialists to complete verification of licensee's operability evaluation. The regional specialist's time spent on reviewing the issue should be charged to this procedure. The inspectors are not required to spend additional time in reviewing an issue if the discrepancies identified do not change the outcome of the operability evaluation.
Generic Letter 91-18, "Resolution of Degraded and Non-Conforming Conditions" and NRC Inspection Manual Part 9900 "Operable/Operability - Ensuring the Functional Capability of a System or Component" provides additional guidance in this area. In particular, as stated in section 4.5.4 of Generic Letter 91-18, some licensees may refer to documents or processes that establish operability of SSCs as JCOs or Justification for Continued Operation. The NRC has defined a JCO as the licensee's technical basis for requesting authorization to operate in a manner that is prohibited absent such authorization. This procedure is not intended to review formal JCOs as defined by the NRC but does cover evaluations referred to by licensees as JCOs which establish operability of structures, systems or components.
See table below for inspection guidance to assist the inspector in selecting inspection activities to achieve each cornerstone objective and to those activities that have a risk priority.
Cornerstone | Inspection Objective | Risk Priority | Example |
Mitigating Systems
Barrier Integrity |
Identify any improperly evaluated degraded and/or nonconforming conditions which could potentially impact SSCs availability and result in an unrecognized increase in risk. | Operating -
mitigating system as
determined by
plant-specific
information or
RIM2.
Shutdown - Mitigating systems that perform key safety functions during shutdown (decay heat removal, inventory control, electrical power availability, reactivity control, and containment) |
Improper conclusion on operability of the HPCI system such that the system could not perform its' function during a station blackout event concurrent with planned unavailability of the RCIC system. |
The annual resource expenditure for this inspection procedure is estimated to be 54 to 72 hours for sites with one reactor unit; 66 to 88 hours for sites with two reactor units; and 78 to 106 hours for sites with three reactor units.
Inspection of the minimum sample size will constitute completion of this procedure in the Reactor Programs Systems (RPS). That minimum sample size will consist of 15, 19, and 22 operability evaluations of degraded and non-conforming conditions in a year at 1-unit, 2-unit, and 3-unit sites respectively.
Generic Letter 91-18, "Resolution of Degraded and Nonconforming Conditions"
Inspection Manual Part 9900, "Operable/Operability - Ensuring the Function Capability of a System or Component"
Information Notice 97-78, "Crediting of Operator Actions in Place of Automatic Actions and Modification of Operator Actions, including Response Times"
Inspection Procedure 71152, "Identification and Resolution of Problems"
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