ML21229A224

Notification of NRC Triennial Heat Exchanger/Heat Sink Performance Inspection (05000275/2021004 and 05000323/2021004) and Request for Information

ML21229A224
Person / Time
Site:	Diablo Canyon
Issue date:	08/17/2021
From:	Vincent Gaddy Region 4 Engineering Branch 1
To:	Welsch J Pacific Gas & Electric Co
References
IR 2021004
Download: ML21229A224 (9)

See also: IR 05000275/2021004

Text

August 17, 2021

Mr. James M. Welsch, Senior Vice President,

and Chief Nuclear Officer

Pacific Gas and Electric Company

P.O. Box 56

Mail Code 104/6

Avila Beach, CA 93424

SUBJECT: DIABLO CANYON POWER PLANT, UNITS 1 AND 2 - NOTIFICATION OF NRC

TRIENNIAL HEAT EXCHANGER/HEAT SINK PERFORMANCE INSPECTION

(05000275/2021004 AND 05000323/2021004) AND REQUEST FOR

INFORMATION

Dear Mr. Welsch:

The purpose of this letter is to notify you that U.S. Nuclear Regulatory Commission (NRC) staff

will conduct the triennial portion of the heat exchanger/heat sink performance inspection at your

Diablo Canyon Power Plant, Units 1 and 2, from October 18-22, 2021. The onsite phase of the

inspection will consist of two reactor inspectors from the NRCs Region IV office for one week.

The inspection will be conducted in accordance with NRC Inspection Procedure (IP) 71111,

Attachment 07, Heat Exchanger/Sink Performance, dated October 21, 2020.

The objectives of the inspection are to verify that: 1) any potential heat exchanger deficiencies

which could mask degraded performance are identified, 2) any potential common-cause heat

sink performance problems that have the potential to increase risk are identified, and 3) the

licensee has adequately identified and resolved heat sink performance problems that could

result in initiating events or affect multiple heat exchangers in mitigating systems and thereby

increase risk.

To minimize the impact the inspection on the site and to ensure an efficient inspection, we have

enclosed a request for documents needed for the inspection. It is important that these requests

are fulfilled as completely and accurately as possible to minimize any additional requests during

the preparation week or during the onsite inspection. The documents have been divided into

three groups.

• The first group lists information necessary for our initial inspection scoping activities.

This information should be available to the lead inspector no later than September 20,

2021. As soon as practicable, the lead inspector will communicate the initial selected

set of 2-4 risk significant or safety-related heat exchangers and/or heat sinks.

J. Welsch 2

• The second group of documents requested includes those items needed to support our

in-office preparation activities. This set of documents, including calculations associated

with the selected heat exchangers and/or heat sinks, should be available no later than

October 4, 2021. This information should be separated for each inspection sample,

especially if provided electronically. Note that the inspectors may identify additional

information needed to support the inspection during this week and will communicate

those requests as soon as practicable.

• The third group of documents requested includes the additional documentation identified

during in-office preparation activities as well as other resource requests necessary to

support our onsite inspection activities. The additional information or resources should

be available throughout the week of onsite inspection activities beginning on October 18,

2021.

All requested documents are to be for the time period from the onsite inspection period back to

the last triennial heat exchanger/heat sink performance inspection. If nothing addressing a

request was performed in that time period, then the request applies to the last applicable

document. If a request does not apply for any heat exchanger/heat sink sample, no response is

necessary. Include all attachments to the requests, especially corrective action program

documents.

We have discussed the schedule for this inspection with your staff and understand that our

regulatory contact for this inspection will be Ms. Amanda Sorensen of your Regulatory Affairs

organization. If there are any questions about this inspection or the documents requested,

please contact the lead inspector, Ronald Kopriva, by telephone at 817-200-1104 or by e-mail at

Ron.Kopriva@nrc.gov.

PAPERWORK REDUCTION ACT STATEMENT

This letter contains mandatory information collections that are subject to the Paperwork

Reduction Act of 1995 (44 U.S.C. 3501 et seq.). The Office of Management and Budget (OMB)

approved these information collections (approval number 3150-0011). Send comments

regarding this information collection to the Information Services Branch, Office of the Chief

Information Officer, Mail Stop: T6 A10M, U.S. Nuclear Regulatory Commission, Washington,

DC 20555-0001, or by e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office

of Information and Regulatory Affairs, NEOB-10202, (3150-0011) Office of Management and

Budget, Washington, DC 20503.

PUBLIC PROTECTION NOTIFICATION

The NRC may not conduct nor sponsor, and a person is not required to respond to, a request

for information or an information collection requirement unless the requesting document

displays a currently valid OMB control number.

J. Welsch 3

In accordance with 10 CFR 2.390 of the NRCs Rules of Practice, a copy of this letter and its

enclosure will be available electronically for public inspection in the NRC Public Document

Room or from the Publicly Available Records (PARS) component of NRC's document system

(ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-

rm/adams.html (the Public Electronic Reading Room).

Sincerely,

Digitally signed by Vincent G.

Vincent G. Gaddy Gaddy Date: 2021.08.17 14:35:25 -05'00'

Vincent G. Gaddy, Chief

Engineering Branch 1

Division of Reactor Safety

Docket Nos. 05000275 and 05000323

License Nos. DPR-80 and DPR-82

Enclosure:

Triennial Heat Exchanger/Heat Sink

Performance Inspection Request

for Information

cc w/ encl: Distribution via LISTSERV

ML21229A224

SUNSI Review ADAMS: Non-Publicly Available Non-Sensitive Keyword:NRC-002

By: RAK Yes No Publicly Available Sensitive

OFFICE DRS/EB1 DRS/EB1

NAME RKopriva VGaddy

SIGNATURE RAK VGG

DATE 08/16/2021 8/17/2021

Request for Information

Triennial Heat Exchanger/Heat Sink Performance Inspection

Diablo Canyon Power Plant, Units 1 and 2

Inspection Report: 05000275/2021004 AND 05000323/2021004

Inspection Dates: October 18-22, 2021

Inspection Procedure: IP 71111.07, Triennial Heat Exchanger/Sink Performance

Inspector(s): Ronald Kopriva, Senior Reactor Inspector (Lead)

Chris Smith, Reactor Inspector

I. Information Requested by September 20, 2021:

1. Heat exchanger/heat sink program documents, including NRC Generic Letter (GL) 89-13

or aging management programs

2. Responses to GL 89-13

3. Different requirements and/or commitments related to GL 89-13 or aging management

programs

4. Heat exchanger/heat sink program self-assessments

5. Updated final safety analysis report (UFSAR), technical specifications (TSs), and TS

bases

6. List of heat exchangers in order of risk significance

7. List of corrective action program documents related to heat exchangers/heat sinks

II. Information Requested by October 4, 2021:

1. For the selected heat exchangers that are directly cooled by the service water system:

a. Performance testing (or equivalent method) documentation, including procedure

b. Periodic flow testing and/or balancing documentation, including procedure

c. Inspection (visual, eddy-current, etc.) and cleaning documentation, including

procedure

d. Tube plugging map

e. Biotic fouling and macrofouling treatment documentation, including procedure

f. Relevant design basis calculations

5 Enclosure

g. Applicable system health report and design basis document

h. Relevant system piping and instrumentation diagrams

i. Heat exchanger design specification and heat exchanger data sheet

j. Heat exchanger preventative maintenance schedule

2. For the selected heat exchangers that are directly cooled by a closed loop cooling water

system:

a. Periodic flow testing and/or balancing documentation, including procedure

b. Inspection (visual, eddy-current, etc.) and cleaning documentation, including

procedure

c. Tube plugging map

d. Evaluation of potential for water hammer

e. Chemical treatment documentation, including procedure

f. Relevant design basis calculations

g. Applicable system health report and design basis document

h. Relevant system piping and instrumentation diagrams

i. Heat exchanger design specification and heat exchanger data sheet

j. Heat exchanger preventive maintenance schedule

3. For the selected ultimate heat sink (UHS):

a. Forced draft cooling tower or spray pond UHS:

i. Calculations demonstrating sufficient reservoir capacity

ii. Documentation of periodic monitoring and trending of sediment, including

procedures

iii. Performance monitoring documentation of heat transfer capability,

including procedures

iv. Performance monitoring documentation of UHS structural integrity,

including procedures

b. Operation of the service water system (SWS) and UHS:

i. List of modifications to the SWS and UHS

ii. Procedures for a loss of SWS or UHS

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iii. Biotic fouling and macrofouling treatment documentation, including

procedures

iv. Chemistry monitoring documentation, including procedures

v. Evaluation of strong-pump to weak-pump interactions

c. Performance testing of the SWS and UHS:

i. Inservice testing documentation of SWS/UHS pumps, valves, and fans,

including procedures

ii. Service water flow balance test documentation, including procedures

iii. Diagnostic testing documentation for valves that interface with safety-

related service water and nonsafety-related or nonseismic piping systems

iv. Performance testing documentation of risk-significant nonsafety-related

functions (or alignments), including procedures

d. Service water and/or closed cooling water system:

i. Inaccessible pipe testing, inspection (visual, ultrasonic, etc.), and/or

monitoring documentation, including procedure

ii. Evaluations of active thru wall pipe leaks

iii. Corrective action documents related to thru wall pipe leakage, including

trend evaluations

iv. For closed cooling water systems, trend data on make-up to the system

v. Protective coatings inspection documentation, including procedure

vi. For deep draft vertical pumps, diagnostic testing (or equivalent method)

documentation, including procedures

e. Service water intake structure (SWIS):

i. Preventive maintenance schedule for traveling screens and strainers

ii. Corrective action documents related to traveling screens, strainers, trash

racks, etc.

iii. SWS/UHS normal and abnormal operating procedures

iv. SWIS inspection documentation regarding structural integrity and silting,

including procedure

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v. Service water pump bay water level instrument documentation related to

setpoints and calibration, including procedures

vi. SWS/UHS water temperature instrumentation documentation related to

setpoints and calibration, including procedures

vii. Evaluations of potential for frazil ice formation

viii. For underwater weir walls, evaluations of potential silt introduction

4. UHS Containment Device or Dam

a. For an above-ground UHS encapsulated by embankments, weirs or excavated

side slopes:

i. Weir or embankment design documentation

ii. Licensee or third-party dam inspection documentation used to monitor the

integrity or performance of the heat sink

iii. Calculations for sufficient reservoir capacity

iv. Significant debris or sediment build-up monitoring documentation in the

UHS

v. Corrective action program documents related to debris, debris, structural

integrity, seepage, settlement, rip rap, etc.

b. For underwater UHS weirs, structures, or excavations:

i. Underwater weirs, structures, or excavations design documentation

ii. Settlement or movement related to structural integrity and/or capacity

monitoring documentation, including procedures

iii. Sediment intrusion monitoring documentation, including procedures

iv. Calculations for sufficient capacity

v. Corrective action program documents related to settlement, movement,

structural integrity, sediment, etc.

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III. Additional Requests During Onsite Inspection Activities

1. Supplemental requests identified during in-office preparation activities

2. Additional requests identified during onsite inspection activities

3. Discussions with relevant subject matter experts

4. Walkdowns of selected heat exchanger/heat sink samples

5. Corrective action program documents generated as a result of this inspection

If the information requested above will not be available, please contact Ronald Kopriva as soon

as possible.

Inspector Contact Information:

Ronald Kopriva (Lead) Chris Smith

Senior Reactor Inspector Reactor Inspector

817-200-1104 817-200-1095

Ron.Kopriva@nrc.gov Chris.Smith@nrc.gov

Mailing Address:

U.S. NRC, Region IV

Attn: Ronald Kopriva

1600 East Lamar Blvd.

Arlington, TX 76011-4511

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