ML20211N568

Submits Clarification of Two Issues Raised in Insp Repts 50-327/99-04 & 50-328/99-04,dtd 990813,which Was First Insp Rept Issued for Plant Under NRC Power Reactor Oversight Process Pilot Plant Study

ML20211N568
Person / Time
Site:	Sequoyah
Issue date:	09/01/1999
From:	Bajestani M TENNESSEE VALLEY AUTHORITY
To:	Reyes L NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
50-327-99-04, 50-328-99-04, NUDOCS 9909130022
Download: ML20211N568 (10)

Text

e Tennessee Valley Authority. Post Offce Box 2000, Soddy Daisy. Tennessee 37379-2000 Masoud Bajestani Site Vee President Sequoyah Nuclear Plant September 1, 1999 Mr. Louis Reyes .

Regional Administrator U.S. Nuclear Regulatory Commission Region II Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85

' Atlanta, Georgia 30303-3415

Dear Mr. Reyes:

'In the Matter of ) Docket Nos. 50-327 Tennessee Valley Authority ) 328 SEQUOYAH NUCLEAR PLANT (SQN) - NRC INTEGRATED INSPECTION REPORT 50-327, 50-328/99 REPORT CLARIFICATIONS The purpose of this letter is to clarify two issues raised in Inspection Report 99-04, dated August 13, 1999,.which.was the first inspection report issued for SON under the NRC Power Reactor Oversight Process Pilot Plant Study. The issues requ!. ring' clarification relate to the design of the storm drain system and to'a safety evaluation prepared by SQN personnel in 1991 and how that evaluation may ha". impacted NRC's oversight responsibilities.

The ins.*ction report indicates that these issues are undergoing NRC review. The information and perspectives that we are providing should be helpful in your deliberations.

Regarding the first issue, Sequoyah will aggressively correct the Lvulnerability of the storn. drain system to heavy rains.

With respect to the second issue,-fuel movement was ceased immediately when the containment issue was identified ,

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PDR ADOCK 05000327

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U.S. Nuclear Regulatory Commission

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_, Sep,tember 1, 1999 (the open penetration issue was raised by the senior resident inspector). Our following clarifications are not intended to ,

-minimize our need to take corrective actions in both of these _d areas. Our discussion is only intended to address actual inaccuracies'and the regulatory importance of these issues.

-As a. result of our' discoveries associated with the closure of '

documents related to the storm drain issue, we are performing a review of significant corrective action program documents issued since 1993. The objective of the review is to identify the subset of these documents that should be t,' reviewed for closure adequacy. We are also preparing a technical specification (TS) change to address ice blowing i and sludge lancing when fuel is being moved. These actions will address the safety aspects of the NRC concerns.  ;

STORM DRAIN SYSTEM The inspection report raises two regulatory issues which have a relationship to the design of the system: why the system was not incorporated into the Maintenance Rule Program and how we dispositioned deficiencies identified following a July 1994 rain.

Storm Drain System Design The yard drainage is a gravity flow system which carries surface runoff from an area north-northwest of the turbine building (including roof runoffs) around the transformer yard

-to the yard drainage pond. The drainage for the switchyard

'is handled by a separate system. The lowest catch basin inlet elevations are in front of the turbine building railroad bay (TBRB) door. As such, overflow in the system will occur there first.

There are no established documented design bases requirements or'SQN criteria since it is a nonsafety-related system and does not perform any functions that are described in the Final Safety Analysis Report (FSAR). In fact, the FSAR .

states that "all underground drains were assumed clogged and the surface drainage to be full." Typically, TVA power plants were designed and sized to handle rainfall events with maximum intensity and duration expected in 25-year intervals. i I

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U.S. Nuclear Regulatory Commission Page.3 September 1, 1999-The' inspection ~ report. states:

The licensee concluded that.the storm drain System

. lacked redundancy in that only 'o ne drain line leads

- away from the catch basins at the entrance to the turbine building railroad bay and that the basins were a t- a ' low point of the storm drain system, with no

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surface path available ' to carry water away from the turbine building railroad bay. Therefore, the inspectors noted that because of _ the design, when the storm drain system capacity is exceeded, the system will overflow from the low point catch, basins into the turbine building railroad bay.

That statement, while correct, should be balanced with the SQN FSAR, which establishes the regulatory design requirements for the system. These requirements focus on the assurance of accomplishing a safe shutdown rather than

' minimization of events. The FSAR (Section 2.4.3.4, Probable Maximum Flood Flow) recognizes that the TBRB could flood and

-states that evaluations.take into account that the turbine, control, and' auxiliary buildings will be allowed to flood.

Structures housing safety ~related facilities, systems, and equipment are protected from flooding during a local probable maximum flood. If de-FSAR provisions are left out, the reader may infer that the system does not meet its design or

. regulatory requirements.

Additionally, the June 1995 SQN IPEEE also evaluates the worst potential flood including probable maximum precipitation on the total watershed and critical watersheds,

including seasonal variations and potential consequential dam

-failures. This document acknowledges the FSAR analysis that i turbine, control, and auxiliary buildings will be allowed'to flood. . The IPEEE concludes that SON design meets the design i

' basis flooding requirements of Regulatory Guide 1.59 and l

-applicable sections of the NRC Standard Review Plan. The IPEEE considerations are important-because they provide the regulatory framework to address flooding.

. Maintenance Rule Considerations -

The inspection report. implies that'TVA did not consider the system during the scoping phase.of the Maintenance Rule. The report states:

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Discussions with the licensee's~. Maintenance Rule specialist indicated that the licensee had not considered or evaluated the site storm drain system o

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U.S. Nuclear Regulatory Commission Page 4-September-1, 1999-during the scoping phase of .nystems to be included under.the Maintenance Rule. The report continues with l  ; Contrary to the above, as of June 30, 1999, the licensee had not included the storm drain system within the' scope'of the Maintenance Rule which is a violation of this requirement.

.. i Based on our review of.the records, the system was considered for inclusion in the Maintenance Rule scope. System No. 040, J

" Station Drainage," includes the. yard storm drains. Station I drainage was reviewed for inclusion in the scope of the rule  !

, by the. SON Maintenance Rule Expert Panel, multiple times. As l* . indicated by panel meeting minutes, on June 23, 1994 and l

June 25, 1996,'the panel concluded that the probability that this system could cause a scram is too small for consideration and excluded it from the scope of the rule.

Also, our personnel considered industry guidance, for Maintenance Rule scoping, during their assessment. NEI 93-01 states,in part. i l

8.2.1.4 Nonsafety-Related SSCs Whose Failure Prevents Safety-Related SSCs from Fulfilling their Safety-Related Function .}

Will the' failure of nonsafety-re ated SSCs prevent safety-related SSCs from fulfilling their safety-

[ related function? ,

This step requires that each utility investigate the j systems and system interdependencies to determine failure modes of nonsafety-related SSCs tha t will  !

directly affect safety-related functions.

As used in this section of the guidelines, the term

'directly' applies to nonsafety-rela ted SSCn:

• Whose failure prevents a safety func. tion fum being fulfilled; or

. * .W hose failure as a support SSC prevents a safety .

function from being fulfilled . . .

. . . The determination of hypothetical failures that could result from system interdependencies but have not previously been experienced is not required.

8.2.1.5 Nonsafety-Related SSCs Whose Failure Causes Srams or Actuates Safety Systems

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U.S. Nuclear Regulatory Commission Page 5 Sep,tember 1, 1999 i

. . . The determination of hypothetical failures that could result from system interdependencies but have not been previously experienced is not required.

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During.the 1994 flooding of the TBRB, that resulted from storm drain' piping blocked by sediment and debris, Unit 1 operation was reduced to 80 percent power as a conservative precaution'to minimize the potential effect of a single component failure. During the 1999 TBRe flooding, no power reduction was.made. Neither of the flooding conditions resulted in any safety-related SSCs from, fulfilling their function and no actual plant level failure occurred which resulted in a sc' ram or safety system actuation. Th6refore, the power reduction was not an automatic trigger for including the drains under the Maintenance Rule as established in NEI 93-01.

On August 24, 1999, our review of the 1999 TBRB flooding condition again-confirmed that the yard drainage system is a i nonsafety-related system and performs no functions that are described in the FSAR. Therefore, based on scoping requirements and guidelines, and reviews of plant industry experience, the storm drain system does not warrant including it in the scope of the Maintenance Rule. Therefore, we believe that our staff gave proper consideration during the scoping phase of the Maintenance Rule. We also consider that their reasoning remains valid today.

Disposition of Corrective Actions Proposed After 1994 Rain .

Storm )

The report states:

Corrective actions to replace the undersized piping of the storm drain system were canceled.

l Based on the review of the 1994 flooding event, the licensee concluded-that the flow configuration of site

. drainage might not be in accordance with the original 1 site design. Corrective actions to address the site '

flow configuration were canceled. l The licensee canceled the above corrective actions on January 6,1999, citing ' insufficient technical merit and/or inadequate economic benefit' . . . .

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. . . Based on the discussions above, the inspectors concluded that the licensee had not taken adequate corrective actions to protect' the 6. 9kv unit boards.

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U.S. . Nuclear Regulatory Commission L Page,6

, Sep,tember 1, 1999 i

.TheLNRC is correct in stating that those proposed corrective measures.were' closed on January 27, 1999, following evaluation by the. Plant Health Committee. However, that

discussion should be balanced with an argument of the reasons p  :(documented in the Master Issue List Cancellation Tracking l -Form) that' guided our personnel in deciding to cancel the proposed actions.

L The additional analysis identified that the 1994 flood l .resulted from blockage of th'e storm drain pipes which lead l_ from the area in front of the TBRB door (approximately 50-60 l percent of the pipe area _was blocked by accumulated debris P and the remaining cross section was almost completely blocked l

, by a ch'emical.sp'ill mat). The spill mat was removed (an

[ opening had to be cut in the drain line to remove the. spill I

L mat) ' and the drainage system was cleaned of debris. To l prevent. recurrence, maintenance actions were implemented to L prevent clogging due to' debris and accountability was

established for spill mat recovery to prevent mats from

! getting into the drain system and causing blockage. Based on a calculation at that time,-the drainage system would not meet the 25-year storm interval; therefore, other actions i were considered possible.

l Subsequently a rain' event occurred (1.38 inches in 15 minutes) that exceeded-the intensity and duration that the calculation identified as maximum capacity. It also exceeded the storm event of July 11, 1994, that originated the adverse j condition report. No overflow or flooding. occurred. This confirmed that the actions taken had corrected and prevented recurrence of flooding for similar or greater rainfall l

. . events. It also demonstrated that the maximum capacity is l .actually greater than previously calculated and was equivalent to a 25-year storm intensity. Based on this new information, it was concluded that the actual capacity was

. adequate without additional corrective actions.

l 1In conclusion, we gave proper consideration to the storm drain system.during the scoping of the Maintenance Rule, and theLcancellation of the corrective actions in 1999 was rooted in legitimate technical arguments. As the inspection report recognizes, it was the deficient temporary modification to the system that prompted the 1999 flooding, i

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'U.S.INuclear Regulatory Commission "Page 7 Sep,tember 1, 1999 l- IMPACT ON NRC OVERSIGHT RESPONSIBILITIES l'

Relative. to open containmerit penet. rations during fuel tmovement,: the inspection report indicates that the failure to  ;

obtain NRC' approval of changes may have impacted the NRC's ability to oversee our activities. j We.suggest that this case did not impact, in any way, NRC's oversight responsibilities. The record is clear that in 1991,-.NRC inspectors, NRR reviewers, and NRC management reviewed the exact same condition the NRC is now evaluating

( and considered the safety evaluation' adequate for the treatment of containment requirements during ice blowing and sludge lancing.

.The 1999 inspection report states: j During the review of the three TS' containment penetration violation examples, discussed above, the inspectors noted that the licensee had revised surveillance instruction (SI) 2-SI-OPS-088-006.0, Containment Building Ventilation Isolation (18 Month /100 Hours /7 Days), used.co verify the containment closure requirements of TS surveillance 4.9.4. The original procedura1 requirements noted that the containment penetrations were operable if they were elther capped or isolated wich a manual isolation valve during fuel ' movement. Revision 8 of the. procedure, da ted October 5,1997, documented in Section 6.3 (3), that three safety evalua tions 'had been performed and approved to configure the system for use during core alterations.' This procedure step allowed the licensee to consider the open containment penetrations during fuel movement or core alterations, as acceptable, although contrary to TS 3. 9. 4

. requirements. In addition, the inspectors noted that prior to Ithe ' October 5,1997, revision to the SI, the licensee was using the deficiency notice (DN) process in order to keep the containment penetrations open during fu'el movement or core altera tions.

- Acceptability of. the DNs on the open penetrations was ,

tied _ to the three safety evaluations, . . . which had

'been initiated in 1991, 10 CFR 50.59 states that the licensee may make changes '

to the facility and procedures as described in the

. safety. analysis report (FSAR), without prior l Commission approvala unless the proposed change  !

involves?a change in'the TS. FSAR Section 15.5.1.2.5, Fuel Handling ' Instructions, states, in part, that fuel

U.S. Nuclear Regulatory Commission Page 8 September 1, 1999 handling instructions are used to ensure safe and orderly refueling opera tions and that these instructions make reference to other system operations documents that specify precautionary steps to assure that the technical specifications are not violated.

Changes were made to SI 2-SI-OPS-088-006.0, a fuel handling instruction, vithout prior Commission approval, that involved a change to the technical specifications, by using the DN process and subsequently a procedural change, both of which did not meet the TS 3.9.4 requirements. The change to the facility and procedures as described in the safety analysis report, without prior Commission approval, that resulted in a change to the technical -

specif.tcations is considered ta be a violation of 10 CFR 50.59 requirements, and is identified as apparent violation AV 50-328/99004-05, Failure to Meet 10 CFR 50.59 Requirements.

The 1999 inspection report acknowledges that NRC had previously reviewed this issue. It states that:

The inspectors noted that the installation and opera tion of the ice blowing piping to the containment penetration and the use of SG sludge lancing equipment penetration were previously discussed in NRC IR 50-327,328/91-23. This IR indica ted tha t, based on

. discussion between Region II and NRR, these two issues were not regulatory safety significant. However, IR 91-23 did not discuss the effect of these conditions on the containment closure TS, nor did it discuss the effect of creating a 10 CFR 50.59 issue with the procedure changes.

We believe that in 1991 the NRC personnel involved did consider containment closure and the effect that approval would have on procedural controls. Inspection Report 91-23, Section 6, states:

. The inspector reviewed TS 3.9. 4.c and questioned the

-licensee as to whether the ice blowing evolutions were .

in compliance with the TS. The licensee stated that a safety evaluation was in place which supported the evolution. The inspectors requested a copy of the evaluation, and on October 23, 1991 the licensee provided the inspectors with a copy of the safety evaluation which was prepared to support. movement of ice into containment during core alteration periods.

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September.1, 1999 The inspectors reviewed _ the safety evaluation . . . .

i 'The inspectors met with licensee personnel on October y 24 to discuss the safety evaluation and ask questions.

The licensee explained that they concluded that no

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10.CFR 50.59 issue existed due to their conclusion l that the installed piping between the containment penetrations and the additional equipment building I

(which was considered to be an extension of the auxiliary building) were extensions of the containment ~

l and meet the requirements of GDC 16. After the i

meeting the inspectors reviewed the licensee's safety evaluation with NRC management . . . . Discussions R with NRR resulted in a conclusion that the issues had no regulatbry significance. This position was -

discussed between the licensee and the inspector.

We believe that the conclusion in Inspection Report 99-04 is

inappropriate. The_ opportunity for NRC oversight has not-l been obviated. Instead, NRC and TVA both now agree that using today's compliance standards, the previous conclusion j was incorrect. NRC personnel--contemporaneous with the safety evaluation--agreed with TVA personnel that ice blowing and sludge lancing activities were permitted by TS 3.9.4.c.

Therefore, the reinterpretation of the aforementioned issues )

should not result in the conclusion that TVA impacted NRC's j oversight responsibilities.

To resolve this issue affecting containment penetrations during fuel movement, we are in progress to revise the TSs to allow the penetrations to be open with administrative controls in place.

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f By taking steps to minimize the probability of rainwater l entry into the 6.9-kV unit boards through use of barriers, sealing of the appropriate conduits during the upcoming outages, review of corrective action document closures for ,

extent of condition, and revision of the TSs to address open l penetrations during fuel movement, the safety aspects of the NRC concerns will be addressed.

In summary, we believe that these two issues have raised engaging topics and our views should help in your analysis of how to treat the regulatory importance of such topics in the future. Hopefully these examples will help us fine tune the new NRC oversight process.

. U . S. . Nuclear Regulatory Commission Page 10 September 1, 1999 Ir you have any questions regarding this response, please contact me at extension (423) 843-7001 or Pedro Salas at extension (423) 843-7170.

Sincerely, be Q 6 O-M. Ba' stani e

cc: r. R. W.-Hernan, Project Manager . .

Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739 NRC Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy-Daisy, Tennessee 37379-3624 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 4