POLICY ISSUE

INFORMATION

August 2, 2002 SECY-02-0148

FOR: The Commissioners

FROM: William D. Travers

Executive Director for Operations

SUBJECT: SUMMARY OF ACTIVITIES RELATED TO GENERIC SAFETY ISSUES

PURPOSE:

To provide the annual summary of activities related to generic safety issues (GSIs).

BACKGROUND:

It has been the practice of the staff since 1983 to provide the Commission with an annual

update of the progress made in resolving GSIs. This practice was reinforced by the

Commission in a staff requirements memorandum (SRM) of May 8, 1998, in response to

SECY-98-030, “Implementation of DSI-22, Research.” In the SRM, the Commission directed

the staff to provide an annual summary of activities related to open reactor and non-reactor

GSIs.

DISCUSSION:

The NRC program for addressing reactor and non-reactor generic issues is delineated in

Management Directive (MD) 6.4, “Generic Issues Program.” MD 6.4 was issued in December

2001. The program described in MD 6.4 consists of seven stages: (1) identification, (2) initial

screening, (3) technical assessment, (4) regulation and guidance development, (5) regulation

and guidance issuance, (6) implementation, and (7) verification. Candidate generic issues may 

be identified by organizations or individuals internal or external to the NRC. Generally, safety 

Contact:

Ronald C. Emrit, RES

(301) 415-6447
The Commissioners 2

concerns associated with operating events, research results, or risk assessments form the

basis for the identification of GSIs by the staff, the ACRS, industry, or the public. After an issue

is identified, initial screening is performed to determine whether it should be processed as a

GSI, excluded from further analysis, or sent to another NRC program for review. In the

technical assessment stage, a determination is made as to whether the issue involves

adequate protection, safety enhancement, or burden reduction. Technical findings are used as

the basis for developing or revising rules, guidance, and programs. In the final three stages,

regulation or guidance is issued by the NRC, implemented by licensees or certificate holders,

and verified by the NRC. GSIs identified after March 1999 have been processed in accordance

with MD 6.4. The Office of Nuclear Regulatory Research (RES) tracks the status of all generic

issues in the agency-wide Generic Issue Management Control System (GIMCS) and

documents the technical assessments and dispositions of all issues in NUREG-0933, “A

Prioritization of Generic Safety Issues.”

REACTOR GSIs

For generic issues associated with nuclear reactor power plants, RES is responsible

for screening all new generic issues and performing the technical assessments of the majority

of GSIs. The Office of Nuclear Reactor Regulation (NRR) is responsible for technical

assessments that require extensive interface with operating plants and for determining the

appropriate regulatory actions for GSIs that have favorable safety and cost/benefit estimates. 

The following is a summary of the activities related to reactor GSIs since the last report to the

Commission in SECY-01-0139 on July 27, 2001.

• One new GSI was identified for initial screening:

192 Secondary Containment Drawdown Time: This issue was raised by NRR and it

addresses the adequacy of the calculations, testing, and acceptance criteria

related to the creation of a vacuum in the reactor building of a BWR following an

engineered safeguards actuation signal.

 Initial screening was completed for the following two GSIs which are undergoing

technical assessment:

188 Steam Generator Tube Leaks/Ruptures Concurrent with Containment Bypass: 

This issue was raised by an RES staff member, and it arose from some

operating and test experience that suggested that a main steam line break in a

PWR can cause resonant vibration of steam generator tubes. This vibration

raised the possibility of steam generator tubes rupturing during the course of an

accident initiated by a main steam line break.

189 Susceptibility of Ice Condenser Containments to Early Failure from Hydrogen

Combustion During a Severe Accident: This issue was proposed in response to

SECY 00-198, “Status Report on Study of Risk-Informed Changes to

10 CFR 50.44 (Combustible Gas Control).” Recent research indicated that, for

PWR ice condenser containments and BWR Mark III containments that have a

relatively low free volume and containment strength, the early containment

failure probability is dominated by hydrogen combustion events. These

containments are equipped with igniters that are intended to control hydrogen
The Commissioners 3

concentrations by initiating limited “burns” before a large quantity accumulates. 

However, if the accident is initiated by a station blackout event, these igniters,

which are AC-powered, will not be available. The issue is whether these igniters

should be equipped with an alternative power supply. The staff briefed the

ACRS on the technical assessment on June 6, 2002, and is working to resolve

the issue on an expedited schedule, as directed by the Commission.

 Based on the results of ongoing technical assessments, one GSI was identified as

needing appropriate regulatory action by NRR:

191 Assessment of Debris Accumulation on PWR Sump Performance: This issue

was raised by NRR because the results of research on BWR emergency core

cooling system suction strainer blockage identified new phenomena and failure

modes that were not previously considered. In addition, operating experience

identified new contributors to debris and possible blockage of PWR sumps, such

as degraded or failed containment paint coatings.

• Two GSIs were closed with no new or revised requirements for licensees

(Attachment 1):

172 Multiple System Responses Program (MSRP): This issue was raised by the

ACRS, during the review of several other generic safety issues (USIs A-17, A-46,

and A-47), because of a concern that, because of scope limitations on each

issue and a possible lack of coordination between issues, there was a possibility

that some potentially significant safety concerns were not being addressed. The

purpose of the MSRP was to gather and review documentation and identify any

issues that may have been missed. The MSRP program identified 21 potential

safety issues. These issues were then addressed as part of the IPE and IPEEE

programs. Some were addressed by explicit request of the licensees, and some

were resolved during the course of the IPE and IPEEE reviews. Following the

completion of the IPE and IPEEE programs, the issue was closed. 

173.A Spent Fuel Storage Pool: Operating Facilities: This issue was raised by two

engineers at a plant who contended that the spent fuel pool failed to meet

regulatory requirements with respect to a sustained loss of pool cooling function

after a loss of offsite power or a loss of coolant accident. To respond to this

concern, the staff performed plant-specific evaluations of certain design features

that increased the potential for a loss of coolant inventory, a sustained loss of

forced cooling, or adverse effects on operating reactor systems from boiling

spent fuel pools. Several licensees took voluntary actions to address the

concerns identified at their facilities. For the remaining facilities, the staff

concluded that no new or revised requirements were justified, and the generic

issue was closed.

Since the inception of the generic issues program in 1976, 833 of the 842 reactor issues

identified have been closed. Two issues are undergoing screening, and the status of

completion of the remaining seven open reactor GSIs is summarized in Attachment 2.
The Commissioners 4

NON-REACTOR GSIs

NMSS is primarily responsible for processing non-reactor GSIs through all stages of MD 6.4. 

The status of the unresolved non-reactor GSIs is tracked by RES in the quarterly updates of

GIMCS. The following is a summary of the activities related to non-reactor GSIs since the last

report to the Commission in SECY-01-0139:

 No new GSIs were identified for screening.

 One GSI was closed with no new or revised requirements for licensees (Attachment 1):

 NMSS-10 Troxler Gauge Source Rod Weld Failures: The staff worked with the

Agreement State of North Carolina to ensure that cracked source rods on

Troxler moisture density gauges were repaired or replaced and that the

manufacturing process was reviewed/modified to reduce the potential for

recurrence. Troxler amended its maintenance procedure to inspect for

cracks and corrected its design. Thus, the issue was closed in November

2001.

Currently, three non-reactor GSIs remain open and the status of their completion is

summarized in Attachment 2.

CONCLUSION:

Since the last report to the Commission on July 27, 2001, two reactor GSIs and one non-reactor

GSI were closed as the staff continued to implement the process of MD 6.4 to identify and

resolve reactor and non-reactor GSIs. The staff will continue to provide an annual update to

the Commission on activities related to GSIs and will inform the Commission of any significant

developments.

/RA/

William D. Travers

Executive Director

 for Operations

Attachments: 1. GSIs Closed since June 30, 2001

2. Open GSIs as of June 27, 2002
The Commissioners 4

NON-REACTOR GSIs

NMSS is primarily responsible for processing non-reactor GSIs through all stages of MD 6.4. 

The status of the unresolved non-reactor GSIs is tracked by RES in the quarterly updates of

GIMCS. The following is a summary of the activities related to non-reactor GSIs since the last

report to the Commission in SECY-01-0139:

 No new GSIs were identified for screening.

 One GSI was closed with no new or revised requirements for licensees (Attachment 1):

 NMSS-10 Troxler Gauge Source Rod Weld Failures: The staff worked with the

Agreement State of North Carolina to ensure that cracked source rods on

Troxler moisture density gauges were repaired or replaced, and that the

manufacturing process was reviewed/modified to reduce the potential for

recurrence. Troxler amended its maintenance procedure to inspect for

cracks and corrected its design. Thus, the issue was closed in November

2001.

Currently, three non-reactor GSIs remain open and the status of their completion is

summarized in Attachment 2.

CONCLUSION:

Since the last report to the Commission on July 27, 2001, two reactor GSIs and one non-reactor

GSI were closed as the staff continued to implement the process of MD 6.4 to identify and

resolve reactor and non-reactor GSIs. The staff will continue to provide an annual update to

the Commission on activities related to GSIs and will inform the Commission of any significant

developments.

/RA/

William D. Travers

Executive Director

 for Operations

Attachments: 1. GSIs Closed since June 30, 2001

2. Open GSIs as of June 27, 2002

Distribution w/atts.:

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NAME REmrit:ecm HVanderMolen JFlack FEltawila

DATE 05/31/02* 05/31/02* 05/31/02* 05/31/02*

OFFICE D:NMSS C D:NRR C D:RES C DEDMRS C EDO C

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DATE 06/10/02* 06/18/02* 07/09/02* 08/02/02 08/02/02
1 

GSIs Closed Since June 30, 2001

GSI

Number

Title Identification

Date

Lead

Office

Status

172 Multiple System Responses Program

(MSRP)

10/1989 RES This issue was identified to address 21 pote

that were raised by the Advisory Committee (ACRS) during the resolution of Unresolved “Systems Interactions in Nuclear Power Pla

Qualification of Equipment in Operating Pla

Implications of Control Systems.” In resolvdeveloped guidance for the review of the sa172 in the Individual Plant Examination (IPEPlant Examination of External Events (IPEEreview of licensee submittals in response to significant contributor to core damage frequidentified. Therefore, the staff concluded thalicensee requirements were warranted. Thuin January 2002. 

173.A Spent Fuel Storage Pool: Operating

Facilities

02/1996 NRR This issue addressed the adequacy of regu

sustained loss of spent fuel pool cooling aftor a loss-of-coolant accident. In resolving tdeveloped screening criteria for reactor acc“Technical Study of Spent Fuel Pool AccideDecommissioning Nuclear Power Plants.” 

were then performed by estimating the freqloss of coolant inventory or a sustained loss estimated frequencies were compared with 1738 and the staff concluded that no new owere warranted. Thus, the issue was closed 

NMSS-10 Troxler Gauge Source Rod Weld

Failures

05/1998 NMSS The staff worked with the Agreement State 

ensure that cracked source rods on Troxler were repaired or replaced and that the manreviewed/modified to reduce the potential foamended its maintenance procedure to inspcorrected its design. Thus, the issue was c2001.
Open GSIs as of June 27, 2002

1 

GSI Number Title Identification

Date

Lead

Office

Status

156.6.1 Pipe Break Effects on Systems and

Components

02/1991 RES This issue addresses the safety co

effects of pipe breaks inside the coadequately addressed in the designanalysis performed by the staff in 1have some safety significance but wmore comprehensive study was unfailure rate data and pipe break meis in the technical assessment stagpresently conducting a comparison Owners’ Group and the INEEL studscreening of the issue. A recommedevelopment of regulation and guidNovember 2002.

163 Multiple Steam Generator Tube Leakage 06/1992 NRR This issue addresses the safety co

multiple steam generator tube leakline break that cannot be isolated. part of the agency-wide Steam Genwhich encompasses several complwith milestones that were schedulebeginning in FY-2001. Completion assessment of GSI-163 is schedule

168 Environmental Qualification of Electrical

Equipment

04/1993 RES Accelerated-aging tests on electric

that some of the environmentally qfailed or exhibited marginal insulatithe cables during or following a desaffect the performance of safety funindustry, NEI and IEEE provided inrelevant information to the staff in Othen, Okonite completed testing of bonded-jacket cables. The results factored into the completion of GSIcontinues to explore voluntary induthe issue. In June 2002, the staff pthe ACRS for completing the technissue.
Open GSIs as of June 27, 2002

GSI Number Title Identification

Date

Lead

Office

Status

2

185 Control of Recriticality Following SmallBreak LOCA in PWRs 01/1999 RES This issue addresses small-break-L

PWRs that involve steam generatiocondensation in the steam generatwater to accumulate in part of the Rcirculation may cause a recriticality excursion) by moving the deborateCompletion of the technical assessscheduled for September 2005.

188 Steam Generator Tube Leaks/Ruptures

Concurrent with Containment Bypass

05/2001 RES This issue addresses the effects on 

generator tube leak and rupture anvibrations in steam generator tubes depressurization. Completion of thof the GSI is scheduled for Septem

189 Susceptibility of Ice Condenser and

MARK III Containments to Early Failurefrom Hydrogen Combustion During aSevere Accident

05/2001 RES This issue was identified with the is

6427, “Assessment of the Direct CoIssue for Plants with Ice Condense

was discovered that the early contain ice condensers is dominated by combustion events. The issue was BWR MARK III containments since volume and strength are comparabcondensers. The staff briefed the Aassessment on June 6, 2002, and issue on an expedited schedule, as Commission. Completion of the tethe GSI is scheduled for December 
Open GSIs as of June 27, 2002

GSI Number Title Identification

Date

Lead

Office

Status

3

191 Assessment of Debris Accumulation on

PWR Sump Performance

09/1996 NRR This issue addressed the possibility 

on the emergency core cooling sysscreen, resulting in the loss of net pmargin (NPSH). This loss of NPSH prevent the flow of water from the sthe criteria of 10 CFR 50.46. A teccompleted in September 2001, conactions may be warranted to ensurmargin for PWR ECCS pumps takicontainment sumps. The PWR indoversight, is developing technical gspecific analyses to determine whewill impede or prevent ECCS operathis GSI, which will include staff vecorrective actions, is scheduled for 

NMSS-7 Criticality Benchmarks Greater than 5%

Enrichment

05/1998 NMSS The staff is developing and confirm

tools for validating criticality calculato process higher enrichments, to bnuclear facilities. Resolution is sch

NMSS-14 Surety Estimates for Groundwater

Restoration at In-Situ Leach Facilities

06/1998 NMSS This issue addresses the developm

(1) calculate surety for ground-watein situ leach uranium extraction facpost-restoration ground-water qualscheduled for September 2002.

NMSS-16 Adequacy of 0.05 Weight Percent Limit

in Part 40

06/1998 NMSS This issue involves two actions: (1) 

technical issues regarding the reguand (2) transfer from licensees of s0.05 percent weight concentration t10 CFR 40.13(a). Options on how jurisdictional and technical issues osource material is part of the activitJurisdictional Working Group. A stto the Commission in March 2001 (staff anticipates providing formal re2003. The transfer provision rule, a00-0201 (September 2000), is expea proposed rule in August 2002.