ML20195B925

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Forwards,For Placement in Pdr,Draft Proposals That Were Provided by Licensee at Request of Staff,In Order to Assist Staff in Developing Commission Paper on Options for Making 10CFR50 More risk-informed
ML20195B925
Person / Time
Site: South Texas  STP Nuclear Operating Company icon.png
Issue date: 11/10/1998
From: Hall J
NRC (Affiliation Not Assigned)
To:
NRC (Affiliation Not Assigned)
References
NUDOCS 9811160319
Download: ML20195B925 (10)
v • d • e


Text

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November 10,.1998

. MEMORANDUM TO: PD IV-1. File i

L James R'. hall, Project Manager ORIGINAL SIGNED.BY:

FROM:

Project Diredorate IV-1 Division of Reactor Projects Ill/IV

' Office of Nuclear Reactor Regulation L

SUBJECT:

~ PROPOSED RISK-lNFORMED REGULATORY CHANGE, SOUTH j TEXAS PROJECT, UNITS 1&2 The NRC staff held conference calls with the licensee on October 29 and November 6, )

199E, to discuss the licensee's proposed risk-informed regulatory changes to enable full l 1

implementation of the graded quality assurance program at STP. These discussions related to l l

l the licensee's letter of October 14,1998, and two subsequent draft proposals, transmitted by electronic mail on November 4 and 6,1998 (Attachments 1 and 2, respectively). The draft ,

i j proposals were provided by the licensee at the request of the staff, in order to assist the staff in i

developing a Commission paper on options for making 10 CFR Part 50 more risk-informed.

The purpose of this memorandum is to place the attachments in the Public Document Room.

l' 1

Docket Nos. 50-498 and 50-499

! ' Attachments:- As stated l

DISTRIBUTION.  !

m e e D ois e s A M ?

- PUBLIC TAlexion DOCUMENT NAME: G:\STPFINAL\ST111298.MEM {

' To receive a copy of this document, indicate in the box C= Copy w/o attact ment / enclosure E= Copy with i attachment! enclosure N = No copy / '

I'-

OFFICE PM/PD4-1 E LA/PD4-1 E' D/PD4-1v b h c i

! NAME- JRHall h CHawes' W JHannon M'{O i

{ DATE- 11//o/98 ff 11/l0jgg ggf/hg

[- OFFICIAL RECORD COPY i 9811160319 981110 * -

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p urug j t UNITED STATES j

g NUCLEAR REGULATORY COMMISSION

          • / November 10, 1998 MEMORANDUM TO: PD IV-1 File

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FROM: James R. Hall, Project Manager (4/\' (  ;

Project Directorate IV-1 Division of Reactor Projects 111/

l Office of Nuclear Reactor Regulation l

SUBJECT:

PROPOSED RISK-INFORMED REGULATORY CHANGE, SOUTH TEXAS PROJECT, UNITS 1&2 l

The NRC staff held conference calls with the licensee on October 29 and November 6, 1998, to discuss the licensee's proposed risk-informed regulatory changes to enable full ,

implementation of the graded quality assurance program at STP. These discussions related to I the licensee's letter of October 14,1998, and two subsequent draft proposals, transmitted by 1

electronic mail on November 4 and 6,1998 (Attachrnents 1 and 2, respectively). The draft proposals were provided by the licensee at the request of the staff, in order to assist the staff in l developing a Commission paper ca options for making 10 CFR Part 50 more risk-informed.

The purpose of this memorandum is to place the attachments in the Public Document Room.

Docket Nos. 50-498 and 50-499 l Attachments: As stated 4

PROPOSED RISK INFORMED REGULATORY CHANGE PURPOSE OF STPNOC PILOT This pilot is a continuation of the GQA pilot which will define the regulatory changes necessary to fully implement risk-informed changes to 10CFR50 and supporting regulations.

Existing Situation:

For components categorized as safety related in the UFSAR, NRC regulations require that these components be qualified to meet the requirements of 10CFR50.49 (Equipment Qualification) and/or 10CFR100 (seismic). Through the Graded Quality Assurance (GQA) risk significance evaluation process (which has been reviewed / approved by the NRC in a Safety Evaluation Report (SER) dated 11/6/97), a number of these safety related components have been determined to be non-risk significant (NRS). If a 10CFR50.59 evaluation is performed to reclassify these NRS components from safety related to non-safety related, an unreviewed safety question (USQ) exists. The USQ results from the deterministic application of 10CFR50.59 where the probability of a malfunction of equipment important to safety may be increased and/or the margin of safety for a Technical Specification will be reduced. The determination that a USQ results is made regardless of the component's relationship to risk and regardless of the size ofincrease.

Although there may be some possibility of other interpretations of 10CFR50.59, the regulations should be applicable in a clear and consistent manner. In addition, the regulations provide no exception for NRS components, and an exemption to the regulations would be required to reclassify components. Also, classifications of systems in the UFSAR could be construed as part of the Quality Assurance program description and 10CFR50.54(a) would require NRC approval of the reclassifications. Finally, there are no provisions in the existing 10CFR50.59 criteria l which would allow reclassification of safety related LOW risk significant components that do not exceed a ' minimal' threshold (i.e., change of 1E-5 is not acceptable) for increases in risk.

STPNOC proposes tht following risk informed regulatory changes as an extension to the existing Graded Quality Assurance pilot process:

Request exemption to the definition of safety related in 10CFR50.2 to allow a definition of risk-important as an alternative to safety related.

The following definition of risk-important is proposed as an alternate to the definition of safety related:

Risk-important Structures, f>ystems and Components (SSCs) may be identified based on approved risk informed processes. The risk-important definition may be used in place of the safety-related definition.

Attachment 1

Allow the application of the risk-informed 10CFR50.59 process, via an exemption, to allow the use of risk information (as used in the NRC approved Graded Quality Assurance process for establishing the risk significance of equipment) to permit minimal increases in risk. The approved STPNOC GQA process for determination of non-risk-significant and low-risk-significant would define acceptable " minimal" changes to the facility.

o I

j Establish that the exemption to the definitions extends to their use throughout the regulations. l i

l Request exemption to 10CFR50.54(a) to remove any ambiguity regarding the application of the already approved GQA process to the reclassification of SSCs.

l . Exempt non-risk-significant components from the requirements of 10CFR50.49,10CFR50.65, l and 10CFR100.

l l

Provide relief as needed from 10CFR50.55a for reduction in ISI/IST scope.

How the above change would be used: l Through the NRC approved Graded Quality Assurance process for ranking component risk significance, groups of risk-important components within a system which have been risk '

ranked as non-risk significant, would be declassified (i.e., classification changed from safety-related or Important-to-Safety to not risk-important).

I The risk informed 10CFR50.59 process described above would be exercised for risk-important l- components within a system which have been risk ranked as LOW risk significant and are l determined to not exceed a ' minimal' threshold for increases in risk would be declassified l (i.e., classification changed from Important-to-Safety or safety-related to not risk-important).

j In addition, the risk informed 10CFR50.59 process would be used to determine if proposed l changes to tN South Texas Project represents a change that is greater than minimal, thus resulting in ,ut unresolved safety question.

Components reclassified as not risk-important would be removed from the scope of the aforementioned regulations (i.e.,10CFR50.49,10CFR50.65,10CFR100, and 10CFR50.55a (as applicable)) pMaining to risk-important equipment. Requests for removal from the scope of other regulations would 'oe submitted at a later time.

The scope of the expanded pilot effort would apply to the systems risk-ranked by the Graded Quality Assurance process. It is expected that the following systems will go through the risk-ranking process by mid-1999, with other systems to follow.

Chemical and Volume Control (CV)* SafetyInjectica (SI)

Radiation Monitoring (RA)* Auxiliary F:edwater (AF)

Essential Cooling Water (EW)* Mechanical Auxiliary Building HVAC (HM)

Emergency Diesel Generators (DG)* Residual Heat Removal (RH) i Reactor Coolant (RC)* Steam Generator Blowdown (SB) l Electrical Auxiliary Building HVAC (HE)* Main Steam (MS)
Component Cooling Water (CC)* Main Feedwater (FW) l 4

, - ,- - , . . ,-m,-- --~,,_--.s -m---,- - -. - - - , - -_ e , ,-_.--

L Essential Chilled Water (CH)* Reactor Containment Building HVAC (HC)

Fuel Handling Building HVAC (HF)

  • Systems which have already been risk-ranked by the GQA program.

EFFECTS:

i i

UFSAR Section 3.2, Classification of Structures, Components and Systems, will be rewritten.

l l The current design and/or procurement specifications will not be amended in such a way that equipment design or performance capabilities will be impaired. Removal or abandonment of equipment supporting non risk significant functions will be performed using the risk

( infu...;d 10CFR50.59 process, t

Non-risk significant equipment will be removed from Technical Specifications where practical (separate license amendments will be submitted) i Non-risk Significant SSCs will be removed the from scope of testing programs in separate submittals such as the following:

Motor Operated Valve Program (routine preventive maintenance still performed) y Air Operated Valve Program (routine preventive maintenance still performed)

ISI/IST Program (50.55a relief requested for those removed from scope)

Snubbers l

Molded case circuit breakers l SAFETY EFFECTS:

i Safety effects have been reviewed and approved by the NRC in the STPNOC Graded '

Quality Assurance applications.

PROPOSED IMPLEMENTATION OF GQA AND RISK INFORMED 50.59 l l- How proposed GQA and Risk Infonned 10CFR Regulation Subject 50.59 and 50.54(a) would be used l 50.49- Equipment Qualification Components reclassified to non-risk-important would be exempted from scope l of50.49.

50.65 Maintenance Rule Components reclassified to non-risk- ,

' important would be exempted from scope -

of50.65. '

4 I

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l L .-50.55a Inservice Testing Components reclassified to non-risk-l important would be removed from scope l

l of 50.55a.

1 I

10CFR100 Seismic Criteria Component reclassified to non risk- 1 important would be exempted from I Part 100 seismic requirements. l 1

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i 5

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PROPOSED RISK INFORMED REGULATORY CHANGE PURPOSE OF STPNOC PILOT This pilot is a continuation of the Graded Quality Assurance (GQA) pilot that will define the  !

regulatory changes necessary to fully implement risk-informed changes to 10CFR50 and I supporting tegulations.

EXISTING SITUATION:

e NRC's regulations require that components categorized as safety related be qualified to meet the requirements of 10CFR50.49 (Equipment Qualification),10CFR100 (seismic),

and other substantive regulations. Through the GQA risk significance evaluation process (which has been reviewed / approved by the NRC in a Safety Evaluation Report (SER) dated 11/6/97), a number of these safety related components have been determined to be non-risk significant (NRS).

  • NRC's substantive regulations provide no exception for safety related components that are NRS, and an exemption from the regulations would be required to reclassify safety-related components to non-safety related. Similarly, there are no provisions in the regulations which would allow reclassification of safety related LOW risk significant components that do not exceed a ' minimal' threshold (i.e., change of IE-5 is not

)

I acceptable) for increases in risk. This is largely attributable to the deterministic definition of" safety related" in 10CFR50.2 and to other references to "important to safety", which I encompasses safety related. The frequent use of these terms throughout the regulations is l probably the largest single obstacle to the application of risk-informed processes.

Therefore, in order to be able to reclassify components, a change in the 10CFR50.2 definition or the substantive regulations, or an exemption will be needed.

  • An exemption or change in the application and use of 10CFR50.59 is also needed. Even if the 10CFR50.2 definition is revisci i 10CFR50.59 evaluation performed to reclassify these NRS components from safety related to non-safety related will likely find that an unreviewed safety question (USQ) exists. The USQ results from the deterministic application of 10CFR50.59 where the probability of a malfunction of equipment important to safety may be increased and/or the margin of safety for a Technical Specification will be reduced. A USQ results regardless of the component's relationship to risk and regardless of the size ofincrease. Therefore,in order to be able to reclassify components without going through the license amendment process, either a change to 10CFR50.59 or an exemption is necessary.

e Finally, classifications of systems in the UFSAR could be construed to be part of the Quality Assurance program description and 10CFR50.54(a) would require NRC approval of the reclassifications. Therefore, a change to 10CFR50.54(a) or an exemption also would be needed to reclassify components.

c1wmoww.%u, w,um Page1of4 Attachment 2

j PROPOSED RISK INFORMED REGULATORY CHANGE EROPOSED RISK INFORMED APPROACH:

STPNOC proposes the following risk informed regulatory changes as an extension to the existing Graded Quality Assurance pilot process: l e Request exemption to the definition of safety related in t0CF R50.2 to allow a definition

! of risk-important as an alternative to safety related.

l The following definition of risk-important is proposed as an alternate to the definition of safety related:

l Risk-important Structures, Systems and Components (SSCs) may be l I '

identified based on approved risk informed processes. The risk-important definition may be used in place of the safety-related definition and in place of the term "important to safety" and any similar terms.

e Establish that the exemption to the definitions extends to their use throughout the regulations.

e Allow the application of a risk-infonned 10CFR50.59 process, via an exemption, to allow the use of risk information (as used in the NRC approved Graded Quality Assurance process for establishing the risk significance of equipment) to permit minimal increases in risk. The approved STPNOC GQA process for determination of non-risk-significant and low-risk-l significant would define acceptable " minimal" changes to the facility.

e Request exemption to 10CFR50.54(a) to remove any ambiguity regarding the application of l the already approved GQA process to the reclassification of SSCs.

!

  • Exempt non-risk-significant components from the requirements of 10CFR50.49, l 10CFR50.65,10CFR100 and other regulations that apply to safety related or important to safety SSCs.
  • Provide relief as needed from 10CFR50.55a for reduction in ISI/IST scope.

I How the above change would be used:

e Through the NRC approved Graded Quality Assurance process for ranking component risk significance, groups of safety related components within a system which have been risk ranked as non-risk important, would be reclassified (i.e., classification changed from safety-related or Important-to-Safety to not risk-important).

c=ceows w , e = Page 2 of 4

l l PROPOSED RISK INFORMED REGULATORY CHANGE I I -

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1 e The risk informed 10CFR50.59 process described above would be exercised for components within a system which have been risk rt.nked as LOW risk significant and are determined to l not exceed a ' minimal' threshold for increases in risk would be reclassified (i.e.,

classification changed from Important-to-Safety or safety-related to not risk-important). In i addition, the risk informed 10CFR50.59 process would be used to determine if proposed changes to the South Texas Project represent a change that is greater than minimal, thus resulting in an unresolved safety question.

e Components reclassified as not risk-important would be removed from the scope of the l

aforementioned regulations (e.g.,10CFR50.49,10CFR50.65,10CFR100, and 10CFR50.55a

(as applicable)) pertaining to safety related or important to safety equipment.

e The scope of the expanded pilot effort would apply to the systems risk-ranked by the Graded Quality Assurance process. It is expected that the following systems will go through the risk-ranking process by mid-1999, with other systems to follow.

Chemical and Volume Control (CV)* Safety Injection (SI)

Radiation Monitoring (RA)* Auxiliary Feedwater (AF)

Essential Cooling Water (EW)* Mechanical Auxiliary Building HVAC (HM)

Emergency Diesel Generators (DG)* Residual Heat Removal (RH)

, Reactor Coolant (RC)* Steam Generator Blowdown (SB) i Electrical Auxiliary Building HVAC (HE)* Main Steam (MS)

Component Cooling Water (CC)* Main Feedwater(FW)

Essential Chilled Water (CH)* Reactor Containment Building HVAC (HC) j Fuel Handling Building HVAC (HF)

  • Systems which have already been risk-ranked by the GQA program.

l EFFECTS:

i e UFSAR Section 3.2, Classification of Structures, Components and Systems, will be I rewritten. Conforming changes will be made in other sections of the UFSAR as necessary.

l

  • The design and/or procurement specifications will continue to maintain required equipment l

l design and performance pm ameters. Removal or abandonment of e(jpment supporting non-

! nsk significant functions will be performed using the risk informed 10CFR50.59 process.

1 o Non-risk significant equipment will be removed from Technical Specifications where practical (separate license amendments will be submitted)

  • Non-risk Significant SSCs will be removed from the scope of testing programs such as the following:

cmmm weo Page 3 of 4

PROPOSED RISK INFORMED REGULATORY CHANGE

=

Motor Operated Valve Program (routine preventive maintenance still performed),

Air Operated Valve Program (routine preventive maintenance still performed),

' ISI/IST Program (50.55a relief requested for those removed from scope),

SAFETY EFFECTSi The risk ranking process, which has been reviewed and approved by the NRC in the STPNOC Graded Quality Assurance application, has determined that there will be no adverse safety affects.

PROPOSED IMPLEMENTATION OF GQA AND RISK INFORMED 50.59 Ilow proposed GQA and Risk Informed 10CFR Regulation . Subject 50.59 and 50.54(a) would be used 50.49 Equipment Qualification Components reclassified to non-risk-important would be exempted from scope of 50.49.

50.65 Maintenance Rule Components reclassified to non-risk-important would be exempted from scope l of 50.65. ~

50.55a Inservice Testing Components reclassified to non-risk-l important would be removed from secpe i of 50.55a.

j 10CFR100 Seismic Criteria Component reclassified to non-risk-l important would be exempted from l Part 100 seismic requirements.

Other substantive Misc. Components reclassified to non-risk regulations important tvould be exempted from these substantive requirements.

a cswmowru u,w-,w Page 4 of 4

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