ML18296A716

Errata for Response to Disputed Non-Cited Violation Calvert Cliffs Nuclear Power Plant - NRC Integrated Inspection Report 05000317/2018001 and 05000318/2018001

ML18296A716
Person / Time
Site:	Calvert Cliffs
Issue date:	10/23/2018
From:	James Trapp Division of Nuclear Materials Safety I
To:	Bryan Hanson Exelon Generation Co, Exelon Nuclear
References
IR 2018001
Download: ML18296A716 (6)

See also: IR 05000317/2018001

Text

UNITED STATES

NUCLEAR REGULATORY COMMISSION

REGION I

2100 RENAISSANCE BOULEVARD, SUITE 100

KING OF PRUSSIA, PA 19406-2713

October 23, 2018

Mr. Bryan C. Hanson

Senior Vice President, Exelon Generation

Company, LLC

President and Chief Nuclear Officer,

Exelon Nuclear

4300 Winfield Road

Warrenville, IL 60555

SUBJECT: ERRATA FOR RESPONSE TO DISPUTED NON-CITED VIOLATION CALVERT

CLIFFS NUCLEAR POWER PLANT - NRC INTEGRATED INSPECTION

REPORT 05000317/2018001 AND 05000318/2018001

Dear Mr. Hanson,

A data error was identified in the Response to Disputed Non-Cited Violation Calvert Cliffs

Nuclear Power Plant - NRC Integrated Inspection Report 05000317/2018001 and

05000318/2018001, dated October 9, 2018 (ADAMS Accession No. ML18282A415). This error

was located on page 2 of the Enclosure, in the second paragraph of the NRC Evaluation. The

error which is approximately 40 percent more than previously aggregated was removed and

did not change the outcome of the NRCs decision that the violation and characterization of the

finding were sufficiently supported in the inspection report. The necessary correction is

reflected in the enclosed revised Enclosure.

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

enclosure and your June 7, 2018, response will be available electronically for public inspection

in the NRC Public Document Room or from the NRCs document system (ADAMS), accessible

from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html.

Sincerely,

/RA J. Nick for/

James Trapp, Director

Division of Nuclear Materials Safety

Docket Nos. 50-317 and 50-318

License Nos. DPR-53 and DPR-69

Enclosure: Summary as stated

cc w/encl: Distribution via ListServ

1 Designation in parentheses refers to an Agency-wide Documents Access and Management

System (ADAMS) accession number. Documents referenced in this letter are publicly-

available in accordance with agency policy using the accession number in ADAMS, except for

documents containing sensitive information in accordance with agency policy.

ML18296A716

Non-Sensitive Publicly Available

SUNSI Review

Sensitive Non-Publicly Available

OFFICE DRP/PB1/BC DRP/PB6/BC DNMS/DD

NAME E. Carfang/eec M. Young/my J Trapp/jln for

DATE 10/23/18 10/23/18 10/23/18

NRC Staff Review of June 7, 2018 Letter

Non-Cited Violation (NCV)05000317/2018001-01

Restatement of the Violation:

On February 23 - 24, 2018, the inspectors reviewed a self-revealed Green non-cited

violation (NCV) of Title 10 Code of Federal Regulations (10 CFR) 20.1501, Surveys and

Monitoring: General, that was identified when Exelon Generating Company (Exelon) did not

make or cause to be made surveys that were necessary for the licensee to comply with the

regulations in Part 20 and that were reasonable under the circumstances to evaluate the

magnitude and extent of radiation levels. As a result of that failure, Exelon did not identify the

presence of dose rates exceeding 1000 mrem/hr within an area being controlled as a High

Radiation Area. Specifically, the licensee had been applying High Radiation Area access

controls for the 11A reactor coolant pump (RCP) bay, based on initial radiological surveys

performed at the start of the outage and historical dose rates in the room from the adjacent

refueling cavity. However, the licensee did not perform subsequent surveys to evaluate the

resulting radiation levels in the 11 RCP bay after changing the storage location of the in-core

instrument (ICI) wires to an area approximately ten feet higher within the cavity. Due to the

change in location of the aggregated highly radioactive in-core instrumentation surveys were

reasonably necessary to demonstrate compliance with Exelon procedure RP-AA-460 section

3.4. The area wasnt identified and controlled as a Locked High Radiation Area, however, until

a worker's electronic dosimeter alarmed.

Licensee Response (Summary):

The NRC issuance of an NCV of 10 CFR 20.1501 is not warranted in that Exelon took adequate

radiological protection actions that were reasonable under the known circumstances for the ICI

wires storage evolution in accordance with 10 CFR 20.1501. Exelon could not have been

reasonably expected to foresee that dose rates in 11A RCP bay would be impacted given the

as-built design features of the 4.5 foot thick refuel pool concrete wall. As indicated in

10 CFR 20.1501(a)(2) surveys must be made when it is reasonable under the circumstances. It

is Exelon's contention that the design of the refuel pool and the procedural requirements

governing its operation are such that it would not have been reasonable to survey the adjacent

11A RCP bay when the ICI wires were stored alongside the refuel pool concrete wall.

Exelon procedure RP-AA-300-1005, Removing Items from the Spent Fuel Pool, Reactor Cavity,

and Equipment Pit, that governs movement of highly irradiated equipment, contains a note

stating that movement of irradiated components past gates, nozzles, and penetrations can

cause streaming and elevated dose rates. However, given that the area of the 11A RCP bay

where the localized high radiation occurred contains none of these features, there was no

reason for Exelon to have foreseen the need to perform a radiological survey in this area. Only

the existence of a previously unknown, undetectable anomaly in the concrete wall resulted in

localized radiation streaming requiring the adjacent, affected area to become a locked high

radiation area. The licensees root cause investigation identified that the most likely cause of

the localized radiation streaming experienced in 11A RCP bay was a previously unknown

anomaly that exists within the tongue and groove construction joint at that location.

1 Enclosure

Although there are numerous external operating experiences where citations have been issued

to licensees for failure to perform adequate surveys, none of these violations were such that any

of these could have reasonably led Exelon to identify the need to perform a survey in the areas

adjacent to the refuel pool concrete wall.

NRC Evaluation:

10 CFR 20.1501, states, in part, Each licensee shall make or cause to be made, surveys of

areas, including the subsurface, that (1) May be necessary for the licensee to comply with the

regulations in this part; and (2) Are reasonable under the circumstances to evaluate -

(i) The magnitude and extent of radiation levels; and

(ii) Concentrations or quantities of residual radioactivity; and

(iii) The potential radiological hazards of the radiation levels and residual radioactivity

detected.

The NRC Region I staff performed an independent review of the assertion that due to the robust

design features of the refuel pool concrete wall, Exelon could not have foreseen the localized

streaming into the 11A RCP bay, and thus your evaluation of potential radiological hazards was

reasonable under the circumstances.

During this evolution, the NRC notes that Exelon made significant changes from past operations

when handling the very highly radioactive in-core detectors. During this evolution, Exelon

aggregated a total of 25 in-core detectors immediately adjacent to the refuel pool

concrete wall. Exelon also stored the aggregated in-core detectors in a new location,

approximately ten feet higher than in previous evolutions. This created higher potential dose

rates in adjacent areas than previously encountered. After storing the in-core instrumentation in

the refueling cavity adjacent to the reactor coolant pump area, Exelon did not perform a

radiological survey in the 11A Reactor Coolant Pump bay or conduct an assessment to evaluate

potential dose rates in the area. In this case, the dose rates in the reactor coolant pump area

exceeded the dose rate that would require locking the area to protect plant workers, by more

than a factor of two. It was not until a workers alarming dosimeter alarmed while working in the

area that Exelon conducted a survey and determined that the area should have been locked.

When performing evolutions that involve movement and storage of highly radioactive sources,

such as the withdrawn in-core instrumentation, it is imperative that licensees take necessary

actions to evaluate the extent of radiation levels present and assure controls are in place to

inform and protect plant workers. The NRC did not find any indication that a review had been

performed in this case; subsequently, plant personnel accessed the area without knowledge of

the potential dose rate and appropriate controls to prevent potential consequences.

In our review, we acknowledged that the follow-up calculations demonstrated that a 41/2 feet of

concrete would have been typically sufficient to effectively shield radiation from the in-core

wires, and that there was no history of documented elevated dose rates in the 11A RCP bay

associated with the movement and storage of spent fuel or in-core instrumentation wires.

Nevertheless, a thorough evaluation of the radiological hazards associated with moving and

storing highly radioactive withdrawn in-core instrumentation may have invalidated the

assumptions of adequate shielding. The inspectors also considered that the 11A RCP bay was

physically accessible for a radiological survey which would have been a reasonable measure, in

this specific case, to assure that adequate shielding is present for the new storage location of

the withdrawn in-core instrumentation. The 10 CFR 20.1003 definition of a survey specifies an

evaluation of potential hazards incident to the production, use, transfer, release, disposal, or

presence of radioactive material, and when appropriate, such an evaluation includes a physical

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survey. In this case, the evaluation did not fully evaluate the adequacy of shielding and a

physical survey was not performed.

Therefore, the staff concludes that during this evolution, the licensee did not comply with

10 CFR 20.1501, in that the licensee did not make or cause to be made surveys that were

reasonable under the circumstances to evaluate the magnitude and extent of radiation levels,

and the potential radiological hazards of radiation levels in the 11A reactor coolant pump bay.

The staff also concluded that this failure was within the ability of Exelon to foresee and correct.

Consequently, the inspectors confirmed that the non-cited violation was correctly documented,

as described in ML18130A878, Calvert Cliffs Nuclear Power Plant - Integrated Inspection

Report 05000317/2018001 and 05000318/2018001, May 9, 2018.

References

1) ML18130A878, Calvert Cliffs Nuclear Power Plant - Integrated Inspection Report 05000317/2018001 and 05000318/2018001, May 9, 2018

2) ML18162A076, Response to NRC Integrated Inspection Report 05000317/2018001 and

05000318/2018001 dated May 9, 2018, June 7, 2018

3) Drawing 61759, Containment Interior Plan @ EL. 45-0, Revision 11

4) Drawing 60061, Civil Standards, Revision 9

5) Drawing 61791, Containment Interior Refueling Canal Reinf. Sheet #1, Revision 1

6) CCNPP 2018001-01 - Post-Event Shielding Calculations, April 24, 2018

7) RV-68, In-Core Instrumentation Removal, Revision 23

8) RP-AA-300-1005, Removing Items from the Spent Fuel Pool, Reactor Cavity, and

Equipment Pit, Revision 1

9) RP-AA-300-1006, Radiological Controls for System Operations with Radiological Impact

in Normally Accessible Areas, Revision 0

10) RP-AA-401, Operational ALARA Planning and Controls, Revision 22

11) RP-AA-460, Controls for High and Locked High Radiation Areas, Revision 31

12) NUREG-1736, Consolidated Guidance: 10 CFR Part 20 - Standard for Protection

Against Radiation, October 2001

13) Survey 2018-003270, Unit 1 CTMT - 11 RCP Bay - Motor Level, February 23, 2018

14) Survey 2018-003297, Unit 1 CTMT - 11 RCP Bay - Motor Level, February 24, 2018

15) Survey 2018-003329, Unit 1 CTMT - 11 RCP Bay - Motor Level, February 25, 2018

16) Survey 2018-003356, Unit 1 CTMT - 69 - Refueling Mode, February 26, 2018

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17) Survey 2018-003400, Unit 1 CTMT Refuel - Refuel Pool, February 27, 2018

18) 18RFO-0015, Combined ALARA Plan - RT 10842007, Remove ICIs IAW RV-68

Procedure, February 2, 2018

19) Regulatory Guide 8.38, Revision 1, May 2006, Control of Access to High and Very High

Radiation Areas in Nuclear Power Plants

20) NRC Information Notice No. 93-39: Radiation Beams from Power Reactor Biological

Shields, May 25, 1993.

21) NRC Information Notice No. 93-33: Sources of Occupational Radiation Exposures at

Spent Fuel Storage Pools, May 9, 1990

23) NRC Information Notice No. 95-56: Shielding Deficiency in Spent Fuel Transfer Canal

at a Boiling-Water Reactor, December 1995

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