ML20080B356

Expresses Appreciation for Professional Conduct of Operator Exams by P Doyle During 941114-16 & Comments on Selected Questions from Written Exam

ML20080B356
Person / Time
Site:	University of Lowell
Issue date:	11/21/1994
From:	Bettenhausen L MASSACHUSETTS, UNIV. OF, LOWELL, MA (FORMERLY LOWELL
To:	Richards S Office of Nuclear Reactor Regulation
References
NUDOCS 9412020126
Download: ML20080B356 (5)

Text

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6 UNIVERSITY OF MASSACHUSETTS LOWELL 1 UNIVERSITY AVENUE go -JP,Fj LOWELL,MA 01854 (508) 934-3365 November 21, 1994 Mr. Stuart Richards, Chief Operator Licensing Branch Division of Reactor Controls and Iluman Factors United States Nuclear Regulatory Commission Washington, D.C. 20555

Dear Mr. Richards,

The purposes of this letter are to express appreciation for the professional conduct of operator examinations by Mr. Paul Doyle during the period November 14-16, 1994, and to comment upon selected questions from the written examination. The individual questions, the comments, and a proposed resolution of each comment are attached to this letter.

If you require additional information, please do not hesitate to call.

Sincerely yours, feh M ee il. ettenhausen s

Reactor Supervisor cc: M. Montesalvo G. Kegel OQIl 9412o201 gDR Aneck 2 osoc5 9411,323 ,

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. CONSIDERATION OFQUESTIONS

. NRC EXAM AT U MASS LOWELL 11/14/94 Question (A.16)

The reactor is suberitical when the console operator adds 0.0080 delta k/k.

(beta eff is 0.0075.) The reactor is:

Discussion:

Since the magnitude of suberiticality is not given, all of the proposed answers can be correct upon assumption of a suitable subcritical k effective.

Pronosed Resolution:

Discard this question.

Question (A.15)

Given the following conditions:

hfelect the cause for the above indications. They are the result of:

c. the fission product poison concentration in the core.

d. rod shadowing.

Discussion:

The question does not address time scale of response. Thus c. could also be considered a correct cause for the indications presented (Reed Robert Burn, pp. 8-19, 8-20).

Proposed Resolution:

Accept c. or d. as correct responses.

Question ( B.1 )

l According to 10CFR20, which of the following is the meaning of " Total Effective Dose Equivalent (TEDE)?" l

a. It is the sum of internal Whole Body Dose and the External Whole Body i Dose. I S. It is the sum of the External Whole Body Dose and the Organ Dose.

l Discussion: l l

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CONSIDERATION OF QUESTIONS NRC EXAM AT U MASS LOWELL 11/14/94 10CFR20.1003 defines TEDE as "the sum of the deep dose equivalent (for external exposures) and the committed effective dose equivalent (for internal exposures). It also defines committed dose equivalent (H-subT,50) as "the dose equivalent to organs or tissues of reference (T)..."

The internal exposures and committed doses are computed on the basis of risk to each organ or tissue.

Proposed Resolution:

Accept either a. or c. as correct answers.

Question (C.4)

Which of the following components penetrates the reactor pool wall?

a. The primary coolant system

c. The thermal column Discussion:

While the primary coolant system is not listed in the referenced section of the UFSAR and does not penetrate the pool wall in the same way as the components discussed in UFSAR 4.1.10, the primary coolant system -

nevertheless does penetrate the pool wall. Because it does penetrate the -

pool walls, anti-siphon protection is provided. See UFSAR 4.2.2 and Figure 4.8 (attached). The four reactor coolant system pipes penetrate the pool liner, enter the pool wall, proceed .rertically and exit the pool wall in the subbasement area enroute to the pump room.

Proposed Resolution; Accept either a. or c. as correct.

Question (C.7)

The situation envisioned in this question did actually occur in the summer of 1994 when a foreign object prevented the float valve from opening fully. The level in the secondary sump decreased. This was observed as abru'r changes in secondary flow rate when air was entrained into the ,

pump suction. The flow changes were reacted to well before any  !

noticeable change in primary pool temperature.

Proposed Resolution:

i

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e CONSIDERATION OF QUESTIONS NRC EXAM AT U MAS 9 I.OWELL 11/14/94 Discard this question. The UFSAR sections referenced with the answer do not directly support the answer given and actual conditions differed from those envisioned.

Question (C.19)

Which of the following instruments monitor for a gaseous release?

a. The two fixed constant air monitors in the reactor building.

S. The stack monitor.

Discussion:

The question omits the origin of the release and the receptor for the release. For a release from the reactor buildinf to the environment, the answer is d. as given. If, however, a release from an experiment is '

considered, 'he release would first be detected by the constant air monitors in the reactor building and provide the information to assess the magnitude and duration of release long before the stack monitor.

Pronosed Resolution:

Accept either a. or c as correct answers.

General Comment:

A few of the examination questions postulate situations outside of Technical Specifications or licensing basis. No specific issue is taken with these, but they would not be suitable questions for use in a question bank.

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