United States Nuclear Regulatory Commission - Protecting People and the Environment

U.S. Nuclear Regulatory Commission

Generic Guidance on Preplanned Alternative Method for High Range Noble Gas Monitoring.

HPPOS-039 PDR-9111210178

Title: Generic Guidance on Preplanned Alternative Method

for High Range Noble Gas Monitoring.

See the memorandum from E. L. Jordan to R. A. Scarano dated

October 22, 1985. This memo states that preplanned

alternate methods of determining noble gas releases as

backups to high range noble gas monitors need not be

continuous monitors. Local radiation survey instruments or

meters on the effluent line are an acceptable preplanned

alternate method.

A request was made for generic guidance during a review of

the proposed alternative method (PPAM) for determining

noble gas releases proposed by Palo Verde Nuclear

Generating Station (PVNGS). The PPAM was required by PVNCS

Technical Specifications to be used as a backup for the

High Range Noble Gas (HRNG) monitors required by

NUREG-0737, Item II.F.1. It was Region V's position that a

backup to the HRNG monitors must be a continuous monitor

with a comparable range. However, based on discussions

with cognizant members of NRR's staff, it was found that

the PPAM does not necessarily have to be a continuous


NRR also stated that the current form of the Technical

Specifications began with a memorandum from D. G. Eisenhut

to T. E. Murley dated October 20, 1980. This memo proposed

that provisions for monitoring noble gas in Standard

Technical Specifications be relaxed. Prior to this time,

the action statement for an inoperable HRNG monitor

required a plant shutdown. No technical basis could be

found for the shutdown requirements; therefore, the

provision for initiating a PPAM was substituted in the

action statement. The intent of the revised action

statement was to ensure that the licensee devised a

feasible method to monitor noble gases as a backup to the

HRNG monitors, but not to require redundant HRNG monitors.

Prior to the issuance of NUREG-0737, interim requirements

for monitoring high range noble gases were specified in

NUREG-0578. During its review of these interim measures,

NRR accepted a method of HRNG monitoring if the licensee

could demonstrate that it was adequate to characterize the

radioactive release without exceeding the dose limits of

GDC-19. Many licensees found that the simplest method was

to install a local radiation survey instrument or meter on

the effluent line. This method was preferable to grab

sampling since it is less dose intensive and easier to

shield. For many plants, the interim system installed to

meet the requirements of NUREG-0578 now serves as the PPAM.

However, taking the position that this is the only

acceptable proposal is a significant deviation from the

position established by NRR.

Regulatory references: NUREG-0737, Technical Specifications

Subject codes: 7.3, 9.1, 12.16

Applicability: Reactors

Page Last Reviewed/Updated Thursday, March 29, 2012