ML031110328
| ML031110328 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 04/08/2003 |
| From: | - No Known Affiliation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| FOIA/PA-2003-0018 | |
| Download: ML031110328 (5) | |
Text
3.4.2 The NRC Failed to Provide Adequate Reactor Oversight Process Guidance 3.4.2.1 Detailed Discussion The team concluded that the NRC failed to provide adequate reactor oversight guidance following the evaluation of numerous light-water reactor inspection program documents, and the performance of interviews with NRC personnel directly involved in the inspection and oversight of Davis-Besse.
NRC inspection procedures were not consistently maintained and implemented at each operating facility. Inspection procedure 62001, Boric Acid Corrosion Prevention Program, was issued August 1, 1991, and subsequently canceled on January 17, 2001. This inspection procedure ensured that the licensee had a program in place to assess leakage from systems containing boric acid. The inspection resources section of procedure 62001 stated that implementation would require 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of direct inspection effort; however, the team did not identify any inspection performed at Davis-Besse using inspection procedure 62001.
In addition, some staff members indicated that they felt that there were not enough hours allocated for complete boric acid program inspections.
The LLTF found that the staff was having difficulty characterizing the significance of the Davis-Besse event. This difficulty appeared to stem from technical limitations of risk assessments and SDPs in that pressure boundary integrity does not appear to be treated explicitly in PRAs. As a result, the type and extent of wastage of the RCS pressure boundary encountered at Davis-Besse appeared to be more within the scope of traditional deterministic analyses than in a risk-informed framework. In fact, as of the time of the LLTF review, the SDP for this event had been in progress for 5 months, with no resolution. Members of the NRC staff expressed the opinion that, in the transition to the ROP, the agency has placed an over-reliance on risk information as opposed to deterministic methods.
The structure of the reactor oversight process (ROP) doesn't allow the implementation of non-baseline inspections unless a greater than green finding is identified. Prior to this event, all ROP Performance Indicators were green, indicating a lack of risk-significant issues at Davis-Besse.
Following the event, the NRC staff has taken several months to characterize the significance determination process (SDP) risk significance of this Davis-Besse condition. Subsequent to the identification of the Davis-Besse head degradation, Region IlIl invoked Manual Chapter 0350, Oversight of Operating Reactor Facilities in a Shutdown Condition with Performance Problems, without meeting the prerequisites. Specifically, Davis-Besse performance was not degraded into the multiple/repetitive degraded cornerstone, or the unacceptable performance columns of the action matrix. The team concluded that timeliness of completion of risk assessments and the procedural inability to consider a significant issue independent of the recent plant risk history, provided an environment such that this issue could be viewed as significant from a deterministic perspective, yet staff would have limited procedural guidance for further NRC action.
(w/i/ 6
Limited experience, coupled with the structured nature of the Reactor Oversight Program (ROP), and several Davis-Besse events during 1998, may have led the inspectors to focus on issues and inspection items that they determined to be of greater significance than the symptoms that Davis-Besse was experiencing. Interviews indicated that a significant focus was placed on managing the ROP effort at the site. The inspectors used self-developed programs to monitor both baseline hours and the number of activities sampled. During the 2000 outage, the resident inspector was not yet qualified to perform independent inspections, the senior resident inspector indicated that the training of his resident inspector suffered due to his focus on ROP implementation and the large number of activities that needed to be followed. One of the inspectors conveyed that many things could not be done because the ROP would not allow it. The team concluded that more experience may have allowed the inspectors to recognize the significance of some items such that they could be folded into the ROP for inspection and keep implementation of the ROP during the outage from becoming a distraction.
One of the inspectors conveyed that the ROP limited his ability to spend much time in containment. For two of the interviewed resident inspectors, Davis-Besse was the only reactor containment structure that they had experience inspecting. The team considered their lack of breadth of experience in this area to be a detriment to their ability to make an experience-based judgement or comparison of the equipment condition in the Davis-Besse reactor containment.
ROP Manual Chapter Attachment 71111.20, Refueling and Other Outage Activities, does not specifically require nor recommend a containment structure closeout inspection. This non-routine inspection would be performed as an added component of Manual Chapter 2515, Appendix D, Plant Status, under the Plant Tours section, increasing the number of hours expended for implementation of Plant Status, a non-direct inspection effort, while not reducing the burden of the additionally required 70-100 hours of 71111.20 outage inspection that impacts the resident staff during a scheduled refueling outage. The team concluded that the implementation of the ROP hours and sample sizes, during high activity times, may be a challenge with limited resources.
Review of Manual Chapter 2515, Appendix D, Plant Status, evidenced a lack of specific guidance on the level of detailed review expected for the corrective action documents routinely initiated by the licensee. A senior resident inspector assigned to Davis-Besse indicated in an interview that he was not aware of reactor head boric acid issues; however, a specific Davis-Besse corrective action document (PCAQ 98-0767), which described several fist-sized clumps of boric acid on the head, was written during his tenure. The team concluded that the daily senior resident inspector focus on the licensee's corrective action program was not adequate to ensure that this significant plant issue was identified for review by the inspection program.
NRC enforcement focus was shifted by the risk-impact of the issue and enforcement actions were not implemented consistently due to differing staff views. Enforcement (EA 97-414) was issued citing the Maintenance Rule (10 CFR 50.65) involving Inconel Alloy 600 RCS instrument nozzle
cracking at SONGS 2 and 3 due to a lack of staff support for enforcement against the licensee's Technical Specification for reactor coolant pressure boundary leakage. In addition, the staff issued the citation as a Severity Level IV, versus a Severity Level IlIl when the staff could not come to full agreement. The licensee presented an argument that was focused on nozzle ejection stemming from catastrophic failure rather than from boric acid wastage.
Risk information may be misapplied in various activities. Risk informed regulation of NRC licensed commercial nuclear facilities includes decisions on allocation of inspections, assessment of the risk significance of occurrences, and the assessment of the severity of regulatory violations. Based on interviews with the staff, the team was concerned that risk models do not appropriately account for degradation of passive components. Some of the staff perceived that the NRC has become risk-based as opposed to risk-informed, that issues cannot be pursued without having a risk number attached to them, and that deterministic safety requirements have been discounted.
Lessons learned weren't learned from previous lessons learned reviews (Millstone, IP2, South Texas).
PI&R? No OBF...Bob?
3.4.2.2 Recommendations 3.4.2.2.1 Recommendations for NRC The NRC staff should review the risk-informed regulatory framework , clearly define which activities should be addressed by risk-informed methods and which should be addressed be addressed by deterministic methods, and establish a means to evaluate the deterministic methods.
Re-evaluation of the implementation of the ROP hours, sample sizes, and resources during high activity times is appropriate.
PI&R guidance should be strengthened: Handoff of issues to the team; Selection of issues; Review of lic binning With aging plants, do more inspection hours on passive components Review inspection expectations during refueling outages...are inspectors spending adequate time in containment Assess need for improvements in Plant Status inspection module 2515 App D Provide inspection guidance to address selected industry operational experience Resurrect 90700 Establish boundaries for use of risk information Establish basis for using deterministic SDPs
Discussion threshold for mid-cycle/end of cycle review assessment Have 'good practices' in the old inspection program been lost? Go back..
Is barrier integrity cornerstone inspection adequate?
Develop usable barrier integrity Pis Inspection guidance for outage influences on work scope Fix ROP guidance to not focus solely on 'high risk" systems/components More review of containment components -
walkdowns Should have independent identification reviewed as part of problems as part of PI&R inspections Do more inside containment inspections as part of License Renewals More discretionary inspection hours in ROP Defibrulate 62001 NRC insp guidance for head inspections (similar to Sgs)
Consider allowing open items for followup inspections in ROP Initiate GC-specific inspection procedures Incorporate GC references in inspection procedures Revisit the policy of not aggregating risk issues/subparts Use traditional enforcement/deterministic SDP for all cross-cutting issues Assess potential predictive PIs and inspections Implement inspection of ECPs for SCWE Inspection guidance for reviewing entry into LCOs Assess ROP to allow inspection of Tmods, workarounds, etc. even if not on list Review of deferred mods Should review mode restraints Develop guidance to focus on repetitive multiple tasks for significance (ALARA)
Focus more inspections on outage periods Inspection guidance to sample licensing requests to understand the basis Followup on cited NOVs Inspection guidance to sample all electronic media (videos, etc)
Review ROP guidance for inspecting plant hardware Incorporate guidance for threshold of sensitivity to RCS leakage....absolute value and change trend Review long-term fixes and their basis Inspect commitments and closure (sample commitments)
Document requirements for video/visual exams (location, etc.)
Develop NRC criteria for inspection of industry initiatives 3.4.2.2.2 Recommendations for Industry None.