Issue Date: 1/17/02
NRC Inspection Manual IIPB
INSPECTABLE AREA: | Temporary Plant Modifications |
CORNERSTONE: | Mitigating Systems (90%) Barrier Integrity (10%) |
INSPECTION BASIS: | Temporary modifications to risk-significant SSCs may adversely affect their availability, reliability or functional capability. A temporary modification may result in a departure from the design basis and system success criteria. Temporary or unrecognized risk changes due to the modification may evolve into high risk configurations. This inspectable area verifies aspects of the associated cornerstones for which there are no indicators to measure performance. |
LEVEL OF EFFORT: | Periodically screen active temporary modifications on systems which are ranked high in risk. Review the details of 4 to 6 temporary modifications a year for a 1-unit site; 5 to 7 for a 2-unit site; or 6 to 8 for a 3-unit site, respectively. Although the sample sizes are an annual goal, the inspection effort can be distributed on a quarterly basis. |
This inspection will verify that temporary modifications have not affected the safety functions of important safety systems.
02.01 | Selection of Temporary Modifications. Select temporary modifications to risk-significant systems. For purposes of this inspection, temporary modifications include jumpers, lifted leads, temporary systems, repairs, design modifications and procedure changes which can introduce changes to plant design or operations. Although the focus of this inspection is on active modifications, inspectors may choose to review a recently removed temporary modification for adequate restoration and testing. |
02.02 | Inspection |
a. Review the temporary modifications and associated 10 CFR 50.59 screening against the system design bases documentation, including Updated Final Safety Analysis Report (UFSAR) and Technical Specifications (TS). Verify that the modifications have not affected system operability/availability. See Inspection Procedure 71111.17, "Permanent Plant Modifications," for additional attributes which may be considered for review. Inspect only those attributes which are significant for the particular modification being reviewed. | |
b. Verify that the installation of the temporary modifications (if accessible) is consistent with the modification documents. Verify configuration control of the modification is adequate by verifying that the plant documents, such as drawings and procedures are updated. including adequacy of operating and maintenance procedures. | |
c. Review post-installation test results to confirm that the tests are satisfactory and the actual impact of the temporary modifications on the permanent systems and interfacing systems have been adequately verified by test. Also, review planned testing after removal of the temporary modifications. | |
d. Verify that temporary modifications are identified on Control Room drawings and at that appropriate tags are placed equipment being affected by the temporary modifications. | |
e. Verify that licensee has evaluated the combined effects of the outstanding temporary modifications in regard to mitigating systems and the integrity of radiological barriers. | |
f. Examine drawings, design and operating procedures, operations logs for evidence of temporary modifications that have not been so evaluated or categorized. |
02.03 | Problem Identification and Resolution. Verify that problems associated with temporary modifications are being identified by the licensee at an appropriate threshold and are properly addressed for resolution in the licensee corrective action program. See Inspection Procedure 71152, "Identification and Resolution of Problems," for additional guidance. |
03.01 General Guidance
For inspection guidance, see Table A below.
Cornerstone | Inspection Objective | Risk Priority | Example |
Mitigating Systems | Identify temporary
modifications
which could affect
the design basis or
the functional
capability of plant
mitigating systems
Emphasize modifications which affect high safety significant Maintenance Rule SSCs/functions or modifications which affect SSCs/functions with high PRA rankings |
Temporary
modifications
which could affect
the design bases
and functional
capability of
interfacing systems
Multiple temporary modifications to a single system or train, especially during outages Temporary modifications which require operator workarounds. |
Use of alternate
material when
specified
replacement parts
are not available
During outages: Temporary electrical power to equipment required to minimize shutdown risk Alternate water sources for equipment cooling or fire protection of equipment required to minimize shutdown risk |
Barrier Integrity | Identify temporary modifications which could affect the design basis or the functional capability of containment or reactor coolant system boundaries | Temporary changes
to containment
isolation motor
operated valve
designs.
During outages: Temporary power improperly routed into containment when the ability to establish containment integrity is still required |
03.02 | Specific Guidance |
a. The review of the design aspects of a temporary modifications should focus on conformance to relevant design criteria not the programmatic elements of licensee programs. | |
b. The review of both the installation of a temporary modification and its retirement is necessary to ensure that the impact on the operation of other equipment is what is expected and previously analyzed, and to verify all other unexpected effects were subsequently evaluated with the results being there is no significant impact on the safe operation of plant or equipment. | |
c. The review of the post-installation test results is to ensure that the parent system remains operable and that its safety function has not been impaired. | |
d. Identification of temporary modifications on drawings and at placement of appropriate tags equipment being affected by the temporary modification should make operators aware of their impact on the operation of plant equipment and components. | |
e. The synergistic effects of outstanding temporary modifications is best judged based on whether there are new impediments to the safety functions of mitigating safety systems, degradation of radiological barriers, and an increase in the consequences of pertinent analyses in Chapter 15 of the FSAR. | |
f. Focus more attention on identifying temporary modifications not previously identified by the licensee if there is no existing program tasked with making interested parties aware of the existence of all temporary modifications. |
The annual resource expenditure for this inspection procedure at a site is estimated to be on average: 31 to 41 hours for one unit; 34 to 46 hours for two units; and 41 to 55 hours for three 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 the review of 4 temporary modifications for one unit; 5 temporary modifications for two units; and 6 temporary modifications for three units.
Inspection Procedure 71111, Attachment 17, "Permanent Plant Modifications"
Inspection Procedure 71152, "Identification and Resolution of Problems"
END